This post details how I replaced the noisy plastic wheels on a Little Tikes push car with high-quality rubber-coated steel wheels. The default wheels are probably OK for grass but on pavement they make a deafening grinding noise and I felt bad for my neighbors (and my son) just going one block over to the park behind our house.
To be clear, upgrading the wheels doesn’t make economic sense: A push car with noisy wheels costs $60 and the “whisper ride” model with rubber-coated wheels costs $80. Four steel wheels will set you back about $40 before considering time and additional parts. But we were emotionally attached to our push car and I thought it’d be a fun project.
Assuming your wheels have 1/2″ ID ball bearings and the axle rod on the push-car is 3/8″ you need 3/8″ ID x 1/2″ OD metal sleeves of some kind. These are not strictly required but the wheels wobble without them
3/8″ push nuts (you may be able to re-use the ones that come one the car if you take them off carefully)
Steps:
Yank the axle-rods off the bottom of the car. The axles snap into the bottom of the molded plastic car body
Get the push nuts off the axle ends and take the old wheels off
Press the 3/8″ x 1/2″ sleeves on the axle ends. This may require some combination of sanding, lubrication and hammering
Mount the new wheels on the sleeves on the axles and put the whole thing back together.
Smoothest-running push-car west of the Mississippi!
UPDATE: As of December 2023 it appears that the HomeBridge plugin is no longer working, possibly because MrCOOL added additional CAPTCHAs or other validation when logging in.
Last year I installed a DIY 4-zone MRCOOL mini-split in our condo. Once I got the system running I wanted to control it through Apple HomeKit. Unfortunately MRCOOL only integrates with Amazon Alexa and Google Home.
I already run HomeBridge to tie together some of our home automation and a supposedly MRCOOL-compatible plugin was available. The plugin is called “smart-cielo” because many mini-split systems on the market share components but are sold under different brands in different configurations, “Cielo” being one.
Until recently the HomeBrdige plugin didn’t actually work with my particular system, but that’s now fixed!
3 head-units controllable from Home app
From memory, here’s a rough guide to using a MRCOOL mini-split with Apple HomeKit and HomeBridge.
Prerequisites:
MRCOOL mini-split with WiFi smart controllers setup and working and you can control your mini-splits from the MRCOOL iOS app
HomeBridge running and working with HomeKit Home Hub. I run HomeBridge in a Docker container on a server in our home, but any HomeBridge setup will work
The network MAC address of each mini-split head unit wifi controller. You can find the MAC addresses in the MRCOOL app or in the admin interface of your WiFi router
Configure the plugin with the username (email address) and password used in the MRCOOL app (this is the password used with the HTTP API that the plugin interacts with to control the head units)
Plug in the MAC address for each head unit in the plugin setttings
Check that it works!
Alternatives
Before the HomeBridge plugin became available I researched and experimented with a couple of other options for integrating “dumb” mini-splits into smart home setups. My notes might be useful is you’re reading this and don’t want to get into HomeBridge. The least broken option I found is the Sensibo Air, and I bought two. They do work (by sending infra-red signals to the head-unit like the normal MRCOOL remote). But overall I think the Sensibos are way overpriced for what they do, and I don’t recommend them. I also remember being annoyed by the requirement for a monthly subscription to access more advanced features.
The best alternative to a HomeBridge HomeKit setup is probably to just stick with the MRCOOL app. It’s clunky and the automation options are simplistic, but once my excitement about HomeKit integration dissipated I found it to be mostly good enough. The reason is probably that the mini-splits are per-room, so getting up and using the remote control is easy. Unlike the whole-house furnace that could only be controlled from the hallway thermostat (before installing an ecobee).
The National Outdoor Leadership School (NOLS) is an American outfit that runs skills-based wilderness courses all over the world. You can take courses for college credit, to pick up outdoor skills like sailing, mountaineering, climbing or backcountry skiing, or simply to have a good time in nature. At the time of writing I’ve done two courses:
2020 Winter Backcountry Touring in the Tetons in Idaho and Wyoming. This involves a couple days of resort-skiing (to get everyone at least basic skiing skills) and class-room avalanche instruction and equipment prep. The rest of the course is in the backcountry, first a couple days in a yurt and the rest camping in snow dugouts (quinzhees). Quite a lot of time is taken up just learning to survive, and with level 1 AIARE avalanche qualification, but there’s also amble time for backcountry skiing.
2023 Alumni Japan Powder Skiing on Hokkaido. This was the first year for this trip (although I was on the 2nd team to go that year). Alumni trips are less focused on instruction and qualification and more on plain fun. So we slept in actual beds (or on tatami mats at least), staying 3 different places on the island of Hokkaido and driving around to backcountry ski spots that the instructors had staked out. And lots of time soaking in onsen natural hot springs after long days skiing.
I really enjoyed both (very different) experiences and would recommend NOLS to anyone interested in surviving and thriving in the great outdoors.
Hokkaido. Photo by Jonathan Mowlavi
I learned of NOLS from reading Chris Hadfield’s (the Canadian commander of the International Space Station) book “An Astronaut’s Guide to Life on Earth”. Chris participated in multiple NOLS courses to prepare for his stint on the ISS. His thinking is that the experiences are similar: You team up with a group of people you’ve never met before in an unfamiliar environment (the Utah desert, Low Earth Orbit) and you have to immediately figure out how to work together and solve problems. He also describes how he found aspects of NOLS’ ethos such as “expeditionary behavior” useful for coping with life in space (and on Earth). “Expeditionary behavior” can be bluntly summed up as “always put the group before yourself and never complain or whine unless your problem is a risk to the success of the group”.
In NOLS, opportunities for personal and leadership development are not based on contrived hardship. Eg. there’s no Bear-Grylls-like challenges involving long pointless marches without supplies (although talking to folks that participated in courses in past decades, fasting was sometimes encouraged). You get plenty of food and work with instructors to make sure you’re bringing all the equipment you need to succeed. Instead, opportunities for development come up when learning new skills, when working together as a team and are offered by the vicissitudes of nature itself.
The ethos of NOLS is hard to pin down and having participated in just two courses I don’t claim to have a deep understanding, but here’s my impression: On one hand, inclusivity and personal reflection are important. Students are encouraged to share their feelings and appreciation for one another, there are daily “readings” of poems and other texts that are then discussed in the group and everyone shares impressions and highlights of the day (the way I’m wired, I always have to get over myself to embrace stuff like that with a group of strangers, but it really does make for a much better experience). But NOLS also embodies a flinty hardness. Nature can be unforgiving, and NOLS wants students to be mentally and physically prepared to deal with the ups and downs of outdoor life. NOLS was founded by Paul Petzoldt who served with the 10th Mountain Division in Italy in WW2 and NOLS works closely with the US Military to provide training to both active duty personnel and veterans. That somehow shines through in regular courses too. The group that had gone before us on the Winter Touring expedition in the Tetons was comprised of Navy SEALS, and they reportedly found it to be tough going which caused some amount of trepidation in our group.
NOLS courses have also been a great way to get to know people that—like me—love being outdoors in winter. As an example, the packing list for the Winter Backcountry Touring trip does not include toilet paper, and you instead do your business by digging a hole in the snow and wiping with snowballs upon completion. What I’m trying to say is that folks that sign up for NOLS courses are typically willing to go the extra mile to have great experiences in life and turn out to be great expedition partners with lots of fun stories to share. I am mindful that NOLS also ends up selecting for students that are like me in less interesting ways, that is white and relatively well off (courses are not cheap, although still a bargain in my opinion). NOLS is working hard to try and change that, but there is clearly a long way to go.
The NOLS instructors on the courses I’ve been on are of a breed apart. I can recognize aspects of my own life arc in them, but for all of them they seemingly decided that being outdoors and sharing their love of nature with others was as-or-more important than office jobs or traditional careers. Some of them have—over decades of NOLS instructing—literally spent half their time “in the field”: sleeping in tents, snow-caves, under tarps or just under the stars. All the NOLS instructors I’ve met are highly educated, knowledgable, resourceful and extremely high energy. NOLS is the only place I know where you’ll find a Rhodes scholar helping you adjust your skis, while unironically holding forth on the spiritual importance of skiing deep powder snow.
Looking a little scruffy at the end of the Teton course
In case you didn’t know, wall outlets with USB ports are a thing. They’re neat for a couple reasons:
Cleaner look, no wall-wart chargers hanging off the wall or falling out the socket
Always there and don’t disappear because someone has to quickly pack for a business trip
110V receptacles can be used for other things that USB-chargers
When we moved in 2017 I installed outlets with USB-A ports in a couple of strategic locations and really liked them. The most-used locations are the kitchen and hallway where we tend to charge phones, bike-lights and so on.
This hallway outlet powers baby-monitor charger, dual Qi charger for AirPods, an IKEA ZigBee repeater and the house thermostat. The ZigBee repeater could probably be in a USB port.
I also installed an outlet with USB-ports behind our bed headboard to charge phones at night. This works fine, but in retrospect was it also relatively pointless: There’s already power strip behind the headboard to power reading lights and other stuff so the USB outlet doesn’t make it any cleaner or more convenient than a wall-wart in the power strip.
12W USB-A type outlets were fine for 2017: USB-C wasn’t all that common (at least not for charging phones and tablets) and you couldn’t get outlets with high-power PD type USB-C ports anyway. That left me without an elegant way to charge our USB-C/Thunderbolt-port laptops. Without having done any research, my understanding is that Ultrabook-style Windows laptops generally require at least 45W to charge, and can typically accept higher charge rates. Way more than what comes out of the USB-A ports.
Laptop charging around the house became less of a problem with the pandemic because both my partner and I now haw full-featured home desk setups that we plug into, but a new one cropped up: HomePod Minis. These are in plain sight in our kitchen and I never really liked the look of the 20W wall-wart with a wire snaking down to the inevitable coil around the base of the speaker. HomePod Minis originally required the full output of the included 20W charger, but a software update dialed that down to 18W—still too much for USB-A outlets.
Not a good look
I’ve periodically checked for outlets with higher-power USB-C ports, and they finally starting showing up this past year. I was slightly annoyed it took so long since it’s an obvious improvement and 3rd party wall-wart manufacturers like Anker were perfectly capable of churning out GAN-based chargers that would fit within the envelope of a standard US wall receptacle. I guess safety regulations, heat-dissipation and reliability requirements combine to make designing a wall-plug receptacle integrating high-power USB-C ports harder than it seems.
Regardless, we’re now spoiled for choice and you can get outlets with (at the time of writing) up to 60W single-port output, enough to charge even relatively powerful laptops. When deciding which ones to get, I was tempted to spring for the most powerful (and expensive) option, also because installing outlets involves turning off electrical breakers and is generally annoying and not something I’d want to do again later to upgrade. But I ended up going for a much cheaper dual USB-C ELEGRP model with 36W max output (18W per port) that I can’t find on Amazon anymore.
Much better. Above the outlet is an off-brand “MagSafe compatible” charger.
I chose those partly because they’re powerful enough to power our HomePod Minis and high-output MagSafe chargers, and partly because I’ve largely switched to Apple Silicon Laptops that have much lower power draw. In fact, both my M2 MacBook Air and (work) M1 MacBook Pro can charge (albeit very slowly) off the old USB-A style outlets (I’m sure someone’s going to point out in the comments that one should only use a proper Mac charger and that I’m ruining my laptop batteries and so on, but I’m going to go ahead and assume that whoever designed the charge controller chose to add support for those charging speeds because it’s safe).
So there you have it: Wall outlets with integrated USB charging ports are awesome and are now powerful enough to power small speakers and even laptops, in addition to charging phones and tablets. And outlets with built-in USB ports look much cleaner than wall-warts that fall out, go missing and take up an outlet.
For the past year and change I used a 32GB non-pro 7th/8th generation iPad for almost all of my personal computing needs. The setup worked really well and I’ve come to really like the device. This somewhat surprised me since I love fast computers and big monitors. So here’s a review of my experiences.
Before the iPad I used a Lenovo X1 Tablet 3rd Gen which is a wonderful device too: very fast (I had the fastest i7-8650U processor), dual Thunderbolt ports and an outstanding 3:2 aspect-ratio high-res screen. Unfortunately it mysteriously stopped working in the summer of 2020 right after the warranty expired.
New M1 MacBooks were expected that fall and since I’ve been drifting into the Apple ecosystem over the past decade I decided to wait to buy a replacement for the ThinkPad and use the iPad to tide me over me over for a couple months (it was a work-gift we had laying around). The first M1 MacBooks came out in November ‘20, but I was somehow underwhelmed—I don’t remember exactly why—maybe something with the limited external monitor support. So I decided to hold out for the follow-up M1-CPU MacBook Pros and the iPad soldiered on. The new MacBook Pros turned out to be super expensive so this winter I ordered what I should have gotten when they came out: a standard M1 MacBook Air.
Ultimately I think I’ll look back on this iPad-period as a Walden-Pond-kinda time where I successfully limited myself to a really constraining computing device, learned some things and then returned to using more powerful and ultimately more productive computers.
Hardware
First off: the base iPad model is a great device. I almost always use it with an Apple Smart Keyboard attached. The Smart Keyboard compares poorly with a ThinkPad keyboard but it’s surprisingly useful and I can type pretty quickly in relative comfort. The big drawbacks are lack of backlighting and the need for a stable typing surface (i.e. no good reclining on couch). If I was going to continue to use the iPad as my main device I’d try out the Logitech Combo Touch.
Some aspects of using multiple keyboard layouts (Danish and US in my case) and the interaction with keyboard shortcuts is not really thought through. For example the Safari tab-cycling shortcuts are cmd+shift+[ and cmd+shift+] which is fine on the US layout. It doesn’t make sense for the Danish one though, and there’s no keyboard shortcut for changing the layout. The workaround if I’m stuck on the Danish layout and want to switch Safari tabs requires clicking the Safari address bar (bringing up they on-screen keyboard controls), selecting US keyboard layout and then cycling through tabs. Not great.
I got a 1st generation Apple Pencil for good measure, just to see how much utility I could get with a full complement of input devices. Besides a few home DIY projects sketches I use the pencil to draw with my 2-year old son, and it’s great for that. No paper, no mess, easy storing and cataloging of drawings. We draw together in the Notes app, but I’d like to learn ProCreate. The pencil is also a nice alternative to finger input because it keeps smudges off the screen. I use a pencil-holder attached to the keyboard cover to hold the non-magnetic 1st gen pencil, which works well.
iPad with Smart Keyboard and Pencil
The hardware design for the standard iPad feels dated. It’s not much changed from the very first iPad: Home button, big bezels, curved back. The 10.2” screen is small, but fine for single-window use in landscape mode. The USB 2 interface on the Lightning port also feels incredibly dated and it makes moving files using flash drives or local 1Gbs networking a drag.
The two worst aspects of the 7th/8th generation iPads were both fixed in the new 9th generation model (which I haven’t tried): The poor front-facing FaceTime camera and the cramped 32GB base storage model. I never take FaceTime calls (with my parents, for example, for them to talk to their grandson) on the iPad even though it has a bigger screen than my iPhone — the camera is just too crummy. For comparison I gifted my parents an iPad Pro, primarily to get them the Center Stage FaceTime feature, and it’s great.
The 32GB storage situation is manageable, if annoying. The problem is not that I have 32GB worth of apps, it’s that Photos hoovers up any residual storage with cached images from my iCloud photo library. I wish there was a way to make Photos more aggressively offload images to free up device storage, or set a limit to the amount of device storage used by the Photos app.
Battery life is pretty OK and certainly better than Windows laptops. On weekends (when I tend to use the iPad a lot) I have to stay on top of charging at night or it’ll run low. Being used to newer iPhones, one thing to note is the lack of fast-charging: Trying to quickly top up the battery with a 30min charge doesn’t make a difference, the iPad has to more-or-less soak up a charge overnight.
iPadOS 15
I got onto the iPadOS 15 public betas as soon as they became available and I suspect that contributed to my positive experience (I never really used an iPad in earnest before, so can’t compare with earlier iPadOS versions). While the iPad screen is too small for actual multi-window use, the improved keyboard shortcuts and widget support probably helped make the iPad a more tenable laptop replacement.
Speaking of keyboard shortcuts, one thing that still bugs me is the semantics of cmd+tab on iPadOS. Coming from full desktop operating systems I have deep muscle memory and always use alt+tab/win+tab/cmd+tab to switch between currently open apps. On iPadOS, however, cmd+tab doesn’t go through “currently open apps”, instead it is apps that the OS hasn’t swapped out for one reason or another. This seems arbitrary and, dare I say, un-Apple-like. A more charitable interpretation is that the cmd+tab app list is “apps that you can switch to really fast” (i.e. without the app having to swap back in) but even that is not really satisfactory: I don’t alt-tab around to find an app I can get going really quickly, I alt-tab to get to some app that I was using a minute ago and now need to use again, whether I have to wait for it to swap in or not.
The upshot is that I tend to use Spotlight search when switching apps which is not lightning-fast, but fine. The 🌐+⬆️ app switcher is also “fine” but not great for keyboard only use, partly because the default focus is on the upper-left corner app, which comes to what I was doing 6 apps back. I’m trying to make myself use 🌐+⬅️/➡️ which is actually fast (until you get to an app that has to swap in). It doesn’t give you an immediate overview of the list of apps you’re tab’ing through though, instead you’re just stumbling along, hoping that the next keypress produces the app you want.
I guess the ultimate cause of this difference is the auto-app-closing behavior in iPadOS. The equivalent in “normal” operating systems is memory being paged to disk, which seems to result in a more seamless user experience, but maybe I just haven’t used a low-memory Windows machine in a long time and it turns out that the iPadOS behavior of almost-fully closing apps that no longer fit in memory is the optimal one (also for battery life).
The base-model iPads have 3GB memory which is probably the right tradeoff to produce a ~$300 tablet, but looking at Marques Brownlee skimming through open apps on a 16GB iPad Pro it sure looks like more memory helps since apps almost never have to be closed by iPadOS.
Apps
iPadOS has had full Safari since version 13 and using an app versus a web-app is often a wash in my experience. Especially because some apps don’t support affordances like selecting and copying text that you’re used to on the web. I still use plenty of apps though, so I wanted to call out some of the high-and-lowlights.
I’m not the first one to point this out, but the Google productivity app suite (Docs, Sheets) is not good on iPadOS and you’re almost always better off using those services with Safari (or Chrome maybe, I didn’t try). I can understand why iPadOS is not a priority for Google, but it’s really a shame since those are otherwise such great services.
I can also understand why Amazon doesn’t prioritize the Apple ecosystem, but Amazon Fresh missing from the Amazon iPadOS app is really frustrating, especially since it’s in the iOS app.
The built-in Apple Files app is terrible. Trying to copy large files around or transfer them over the network will reliably cause the whole iPad to grind to a halt, the only action I’ve found to do that. It’s like Apple ended up in some strange middle-ground between the paradigms of strong on-device processing and cloud-first data storage, and the result is frustration. The file transfer problem is particularly frustrating because it’s been adequately solved on literally all other computing platforms I’ve used in the past decade. I tried a handful of 3rd party file apps but they either sucked in different ways or came with adds and other cruft.
The Microsoft Remote Desktop app is great. Part of the reason I could make do with just an iPad for so long was definitely that I had a full Windows VM on my home server that I could access to do the few things that just didn’t work on the iPad. The Remote Desktop app mostly bridges the iPad/Windows divide with sane defaults for what keys and keyboard shortcuts do and clearly a lot of thought and care has gone into making that seamless. The contrast with remote desktop’ing into a Mac is stark. Apple provides no built-in way to do this (from an iPad) and the assorted VNC-based apps and tools in the Apple ecosystem compare very poorly with Microsoft Remote Desktop.
The Photos app is good but as mentioned above its tendency to gobble up storage is a problem. There’s a very strange incompatibility where videos shot on my iPhone 12 Pro Max in 4K 30fps cannot be edited in the Photos app on the iPad. iMovie on the same iPad can edit those videos just fine, so it’s not a hardware or codec limitation. I prefer cropping videos on the iPad over my phone, but having to install 750MB of iMovie (which is also more cumbersome for simple things than editing right in Photos) ruins that.
Editing videos shot on iPhone doesn’t work in Photos app on iPad
Summary
So would I recommend a base-model iPad for your main computing device? No, not if you like “normal” computers and can afford a decent Mac or Windows laptop. And I’m not sure I’d feel different if I had tried this experiment with an iPad Pro, the OS is just too quirky and limited. But for less than $300 these iPads are incredible devices and I heartily recommend them to anyone than can live within the constraints or for whom the constraints (and the improved reliability and stability you get as a result) are actually a benefit.
This post covers how I upgraded our home thermostat from a battery-powered two-wire setup to an Ecobee3 Lite supporting both heating and fan-only modes. I wanted the fan-only mode to circulate air in our two-level condo where hot days often result in a hot and stale 2nd floor and a frigid 1st floor.
Note that I’m neither an electrician nor an HVAC pro and it’s very possible that what I did is a very bad idea. But it worked for me, so I thought I’d share.
Our house only has two wires running from the thermostat mount in the condo to the furnace in the garage, just enough to complete an electrical on/off circuit used to tell the furnace whether to heat or not. This is the dreaded “no C-wire” situation with no way to power a smart thermostat and no way for the thermostat to tell the furnace to just run the air circulation fan. Our furnace is relatively modern and has more wire terminals, but running additional wires from the condo down to the garage was not really an option.
Two wires 🙁
To overcome this I bought two items:
A 24V transformer that’s plugged into an outlet near the thermostat mount inside the condo. This powers the Ecobee
A Fast-Stat Model 1000. This gizmo consists of sender (inside) and receiver (furnace) components. It works by multiplexing additional control signals (for fan-only, in my case) over the single installed wire-pair. Higher-model-number Fast-Stats can provide more virtualized wires, but I just needed one
The first step was to install the Fast-Stat. It comes with easy-to-follow instructions and wiring it into our furnace’s clearly labeled bread-board-like circuit board was relatively simple.
Furnace-side Fast-Stat install
With the Fast-Stat installed I could run both heating and fan-only modes using the old dumb thermostat, validating that it’s working correctly.
Next, I mounted the new Ecobee and wired it up with the wires from the Fast-Stat and from the 24V transformer. The first time I did this, I got it wrong. I wired the transformer wires to C (“Common”) and R(c) (for “Red-Cooling”, I believe) and put the black wire in R(h) (for “Red-Heating”). I guess I thought that the Ecobee wanted it that way because it’s going to be running the heating system (hence R(h)) and the transformer instructions said to connect to C and R(c) wires.
With that ready the Ecobee turned on fine and all the wires showed up in the Ecobee configuration interface. Heating even worked! I couldn’t make the Ecobee run the fan-only mode, however, and at this point I actually gave up on fan-only for a couple of months, happy that I could at least control heating using the fancy new smart thermostat.
This weekend I had a chance to fiddle with the thermostat some more, and managed to get everything working. First I tried just connecting the G (“Green”) terminal (which runs just the fan) to R(h) with a piece of wire and the fan duly started whooshing air around. This was not surprising since the old dumb thermostat could to that too, but at least it showed that the wiring and connections on the Ecobee mount were OK.
Then I tried simply reversing the inputs to the R(c) and R(h) terminals so the transformer wire went to R(h) and the furnace control wire to R(c). In that configuration the Ecobee wasn’t getting any power and wouldn’t turn on. The breakthrough was to simply jam both the transformer and the furnace control wire into the R(c) terminal of the Ecobee mount. Re-reading the Ecobee instructions that makes some sense because the Ecobee wants to always use the R(c) terminal for systems with only one R-wire.
Working setup
In spite of much googling I never found complete instructions for combining a 24V transformer and a Fast-Stat to make an Ecobee work for both heating and fan-only with a two-wire system. I hope this post helps others with the same setup.
Podnanza is a simple screen-scraper/feed-generator that I built for my own amusement to podcast shows from Danish Radio’s (DR) Bonanza archive. Check out the Podnanza announcement post for details. This post describes how Podnanza was built using ASP.NET Core running on AWS Lambda. The Podnanza source code is on GitHub.
I’ll start by admitting that AWS Lambda is the wrong technical architecture for Podnanza. Nothing’s wrong with Lambda, but Podnanza is a set of very static RSS feeds: The shows are from DR’s archive and don’t change or get new episodes. A simpler Podnanza implementation would have been a static-site generator that scraped the archive and put the XML RSS feed files in AWS S3.
I opted for Lambda for the very bad reason that I wanted to learn about serverless/function-based development by implementing a “real” project, and Podnanza was the realest small-size idea on my mind at the time. At least it’ll only be me that has to deal with maintenance of the over-complicated setup.
FaaS and HTTP Apps
Working (as I do) on PaaS/FaaS/Serverless products one might encounter arguments like:
FaaS is event-based programming and HTTP requests can be thought of as events. If a PaaS platform has good autoscaling and scale-to-zero (idling) then separate FaaS-features are not needed—people should just build FaaS apps as normal HTTP services.
Or the other way around:
If we have FaaS and event-based programming, why would we also support long-running processes for serving HTTP requests? People should just build HTTP apps from FaaS features since dealing with HTTP requests is an example of handling events
In the abstract, both of these of these statements are correct but they also obscure a lot of useful nuances. For example, even the slickest HTTP app platform pushes some HTTP handling overhead onto developers. Programs that only have to accept events through an interface defined in an SDK maintained by the FaaS platform can be a lot simpler than programs dealing with HTTP, even when a HTTP endpoint is only required for ingesting events. And because event-handling is a more constrained problem than general HTTP, platform-provided tooling such as SDKs and test-mocks can be more targeted and effective.
Similarly, forcing all HTTP apps to be built by handling events coming through a FaaS platform event interface is not ideal either:
Lots of apps have already been built using HTTP frameworks like Node.js Express, and those apps would have to be rewritten to conform to the event interface
Many developers are very experienced and productive building HTTP apps using existing HTTP frameworks and it’s not worth it for them to ditch those frameworks for an event-based HTTP model, even if it comes with slightly reduced management overhead
FaaS interfaces are still largely proprietary and platform-specific, causing lock-in (although middleware like the Serverless Framework can help mitigate that). HTTP apps, on the other hand, can run anywhere
ASP.NET Core on AWS Lambda
With all that out of the way, let’s look at how AWS made ASP.NET Core respond to HTTP requests on Lambda. Spoiler alert: It’s a pretty clever blend of the two dogmas outlined above.
Generally serverless “web apps” or APIs are built with Lambda by using an AWS API Gateway (optionally combined with CloudFront for CDN and S3 for static assets) that sends API Gateway Message Events to a Lambda function. The events are basically JSON-formatted HTTP requests, and the HTTP “response” emitted by the function is also JSON formatted. Building a serverless .NET web app on top of that would be pretty frustrating for anyone familiar with ASP.NET because all of the HTTP, MVC, routing and other tooling in ASP.NET would not work.
But here’s the genius: Because the ASP.NET Core framework is fairly well-factored AWS was able to build a HTTP request pipeline frontend (Amazon.Lambda.AspNetCoreServer) that marshals API Gateway Message Events and feeds them into the rest of ASP.NET Core as if they were normal HTTP requests (which, of course, they were before the AWS API Gateway messed them up and turned them into JSON). The AWS blog post has more details and also diagrams (reproduced below) showing the two execution models.
The result is that ASP.NET Core web apps can be debugged and tested locally using the “standard” IIS/Kestrel-based pipeline and then built and deployed using the Amazon.Lambda.AspNetCoreServer based pipeline for production deploys to AWS Lambda. AWS even ships Visual Studio plugins and dotnet newtemplates that make getting started simple.
While neat, the Lambda approach completely ignores the ideal of dev/prod parity and the execution framework during local testing (with IIS/Kestrel) is very different from the production environment. Somewhat to my surprise I encountered zero problems or abstraction-leaks with the exotic HTTP setup when building and evolving Podnanza, but I suspect that more complex apps that make fuller use of HTTP semantics might see oddities.
Summary
Podnanza has been running without a hitch on AWS Lambda for more than 6 months at the time this post was written, typically costing around $0.20/month including CloudFront and API Gateway use. I’ve pushed multiple tweaks and improvements without issue during that time, always using the dotnet lambda package. On a side-note I admire the AWS .NET team’s zeal in building the Lambda deploy flow into the dotnet tool, but I wonder if it would have made more sense to just add it to the aws CLI that developers use to complete other AWS tasks. Also note that I haven’t built any CI/CD or GitHub-based deployment flow since it’s just me working on and deploying Podnanza. Maybe improving that would be a good way to learn about GitHub Actions…
This post is likely only interesting if you’re a Danish-speaker.
Podnanza is a screen-scraper and feed-generator that turns radio series from the Danish Radio Bonanza archive into podcast feeds for easy listening in your favorite Podcast app. I built Podnanza mostly for my own enjoyment because I wanted to listen to children’s radio-dramas edited and narrated by Carsten Overskov.
Here are some example feeds with links to the series’ pages on Bonanza:
I’ve submitted one of the feeds to iTunes to see if Apple will list them (they might not). UPDATE: Apple published the podcasts and I’ve updated the links.
If the links are not working for some reason, here’s how to manually add the raw RSS feeds in the iOS Podcasts app:
All of Overskov’s shows were aired as part of DR’s “Children’s Radio” segments but as far as I remember, at least the Ivanhoe edit/re-telling was very graphic and raunchy (much more so than the “adult” original). I didn’t actually listen to the shows as a kid, but heard what must have been a re-airing of Ivanhoe in 1-hour segments on my first minimum-wage job out of high school, assembling door knobs. The shows were reportedly also very popular with long-haul truck drivers.
It’s funny to me that the progressive/left-leaning folks at DR (Carsten Overskov got into trouble for hollering “Advance, comrades—the microphone is with you!” while covering an anti Vietnam War demonstration in front of the American Embassy in Copenhagen in the ’60s) spent all this time retelling and recording Victorian era English novels, but who am I to complain? They’re the same novels my dad read aloud to me when I was a kid—King Solomon’s Mines is the first novel that I remember hearing.
Podnanza dynamically scrapes the Bonanza site to generate the Podcast feed, which is then cached for performance. If you find radio shows on Bonanza that you’d like to consume as a Podcast, simply find the identifier that DR uses for that particular series and stick it at the end of the Podnanza URL. For example, https://www.dr.dk/bonanza/serie/276/ivanhoe/ is the URL for Ivanhoe, so you want http://p.friism.com/p/276 for the Podnanza URL that you add to your podcast app.
Podnanza does support HTTPS but iTunes’ very dated list of trusted CA’s doesn’t include AWS (where Podnanza runs) so I’m just using HTTP urls for now. The code powering Podnanza is on GitHub in case you find bugs or want to help out.
Overskov died a couple of years ago but his work lives on in Danish Radio’s awesome online Bonanza archive. I hope Podnanza will help make consuming these shows easier, and that you’ll enjoy listening to them as much as I know I will.
My girlfriend and I got a MATE e-bike last year. While far from perfect, it has proved a solid purchase and we’ve put more than 2500km on it. Read on for a review and details on some of the modifications I’ve made to our MATE.
We ordered a black 350W MATE S fairly early in the Indiegogo campaign in the fall of 2016. Including shipping I think the price came to around $1000. Production and shipping took a long time and the bike arrived in mid 2017.
Mate before additions
Quality
To be clear, the MATE is not a high quality e-bike. But it’s relatively well-designed, it’s well-appointed with disc brakes front and rear, front and rear suspension, a good battery and a powerful motor. It’s a good deal for the money in my opinion.
On our bike, the screw that holds hasp that secures the collapsing handlebar came out within the first couple days of use (I suspect it hadn’t been threaded in properly). This would cause the steering tube to collapse while riding (not a good thing). Zip-tying the hasp in place solved the problem, and I notified MATE hoping they’ll improve quality control on that component.
After a year of heavy use, 6 spokes on the rear wheel had snapped. Replacing them was not a big deal, but still annoying.
The pedals that come with the bike are of a collapsing type, but they tend to give a little when pedaling hard—not a confidence inspiring trait. I plan to replace them with some leftover regular pedals that I have lying around.
Weight
The MATE is heavy at 23,7 kg. I had hoped that my girlfriend would want to ride the bike to BART, collapse it, take it on the train and then put it back together to ride the final stretch to her office. This proved unrealistic: The bike is way too heavy to schlep around public transport. I sometimes ride the MATE to work and can only barely haul it up a flight of stairs on the way to the bike locker. No single component tips the scales: The battery is heavy, the rear wheel (with motor) is heavy, and the frame is heavy.
Before riding the MATE I thought the suspension (front telescoping fork, rear articulated sub-frame) was a gimmick. But taking into account the weight, the suspension does really help absorb bumps from holes in the road and going up or down curbs.
Bits and pieces
Other than lights and a lock, one of the first things I put on the handlebar was this phone mount. It has wrap-around elastic bands to secure the phone in place. The MATE comes with a USB port for phone charging under the handlebar. Combined with Bluetooth headphones, I can be in meetings while riding to work (with my phone charging), occasionally glancing down to see what’s going on with slides and presentations in the Hangout. I also installed a cup-holder (per girlfriend request), but that just got in the way and I’ve since removed it.
Cupholder and phone mount
Out of the box the MATE e-assist is speed limited to 30km/h. The governor is easily removed (you can Google for instructions) and then the 350W model will go about 40km/h on a flat, even road (40km/h is probably about as fast as you want to go by the way—my eyes start to water up at that speed, and it’s enough to more-or-less keep up with city traffic).
One funny problem is that even the smallest sprocket on the rear cassette is fairly large, and that means low gearing. I suspect the designers couldn’t put on smaller sprockets because they had to fit the motor and power cable through the hub. The result is that you can’t help the bike accelerate above around 30km/h because it’s not possible to pedal fast enough. To remedy this I switched in a bigger 58-tooth front chainwheel to get higher gearing, which helped a little bit.
We’ve gone through several sets of disc brake pads already. Part of the reason is probably the weight and speed of the bike, but I also find that my riding-pattern is different with a motor. Riding my non-e-bike, I carefully try to conserve momentum, don’t accelerate if there’s a stop coming up and generally try to brake as little as possible. Once I have a motor to help me along, all such caution goes out the window, and I just mash the accelerator whenever there’s a bit of open pavement in front of me. That also means way more stopping and more wear on the brakes.
The brake calipers and pads are some sort of off-brand type, and the MATE web-site doesn’t have info on getting replacement pads. I thought bb5 pads would work, but they don’t, so I ended up installing a new Avid BB7 caliper for the rear wheel. This also has the advantage of greater pad surface area which means more stopping power and less frequent pad changes.
Same as the brake pads, tires wear out pretty fast and I had lots of flats (maybe partly because the factory tires are not of the highest quality). As replacements, I installed heavy-duty German Schwalbe Marathon tires. They’re designed for e-bikes and good for up to 50km/h. I haven’t had a single flat since putting those on. They are heavy, however, and (in my experience) almost impossible to seat, even when applying lots of lubricating soap and elbow grease.
Carriers
I use the MATE to get groceries, so I wanted a good basket. Unfortunately, that can be hard to find for collapsible bikes with 20″ wheels. I ended up getting a cheap aluminium front rack that mounts on the fork and zip-tied an IKEA wicker basket to that. This worked OK, but the rack is flimsy and I already had one crumble on me.
The front of the bike now has a Wald 157 Giant Delivery Basket. This is a great product, but it required extensive modification to mount low over the wheel on the MATE: I had to shorten the wheel-hub poles and since it doesn’t sit up high on the handlebar it’s secured with a stay that connects to the front fork.
Since the basket is not hanging on the handlebar, the weight of the basket and its content would have been on the thin quick-change axle-skewer. Some of the weight is transferred to the actual fork when the skewer is tightened, of course, but it still seemed like a precarious setup. To help transfer load to the fork I remounted the carcass of the second cheap aluminum front rack and screwed and zip-tied it all together. The result is sturdy and doesn’t sway or wobble at all.
A Durban rack (UPDATE: This rack is no longer available from Amazon—searching for “bike rack 20 inch” or “folding bike rack” seems to surface similar-looking products) is mounted on the rear wheel and two Wald 582 collapsible baskets are suspended on the sides. These are perfectly sized to hold a grocery bag each. One thing you have to look out for when mounting a rack on the rear of the MATE is to either attach it only to the unsprung subframe (most practical option in my experience) or to the sprung frame. If you use mounting points on both, the suspension loads will be transferred to the rack instead of the shock and you’re going to have a bad day.
Loaded with groceries
Note that in my setup, both the front and rear racks are mounted on the unsprung suspension components. This is not ideal because it makes the suspension less effective and causes groceries to bounce around more. I don’t think there’s a good alternative for a compact bike like this, however, and it hasn’t proved a problem since I tend to ride carefully when fully loaded anyway. Also note that, even though the frame is heavy, it’s not as stiff as one could have hoped, and that shows when the bike is carrying a lot of weight.
The good part is that all the luggage ends up being mounted pretty low, which helps with stability.
Baskets and x-large sprocket
Summary
Overall, I think the MATE is a good deal and would recommend it for anyone looking for a simple and cheap e-bike to get around town. With a few additions, it can be turned into a great commuter bike and grocery hauler. Between the three Wald baskets, I can carry 5 full grocery bags and the motor means I don’t even break a sweat trucking them up San Francisco hills to get home.
My home computer is a tricked-out 2011 ThinkPad W520. I find it to still be very fast and a joy to use. This post describes upgrades I’ve made to keep the machine relevant in 2018.
I got the W520 as my main work laptop in late 2011. In fact, you can see it in this 2012 AppHarbor housewarming invitation connected to two 23″ portrait-mode monitors. I spec’ed it with a quad-core/8-thread i7-2820QM 2.3/3.4GHz 8MB L3 processor, 8GB RAM, and two 320GB spinning disks configured for RAID 0 (You had to order with a RAID setup to get that option, and 320GB disks was the cheapest way to do that).
After taking delivery I switched out the disk drives for two 120GB Patriot Wildfire SSDs, also in RAID 0. The result was a 1GB/s read-write disk array which was good for 2011. At some later point I upgraded to 32GB RAM (4x8GB)—memory was much cheaper back then. I also added a cheap 120GB mSATA SSD for scratch storage (the mSATA slot is SATAII, so somewhat slower).
After leaving AppHarbor I used the W520 only sporadically for testing Windows Server pre-releases and running test VMs. Whenever I did, though, I found myself thinking “oh year, this is a really neat and fast machine, I should use it for something”. In 2017 I moved into condo and got to have a home office after 7 years of moving between assorted shared San Francisco houses and apartments. For my home PC, I wanted to see if I could make the W520 work.
My main requirement was a system that can power a 4K monitor running at 60hz. The W520 has a reasonably fast Nvidia discreet GPU and can render 4K just fine using remote desktop, but neither the VGA port nor the DisplayPort on the laptop can push out that many pixels to a plugged-in monitor.
Luckily the W520 has a bunch of expansion options that can potentially host a more modern graphics adapter:
2xUSB 3.0 ports
Internal mini-PCIe slot used for WiFi adapter (the Lenovo BIOS whitelists approved devices however, so a hacked BIOS is required to plug in anything fun)
ExpressCard 2.0 slot
ExpressCard technology was on the way out in 2011 but had reached its zenith and in the W520 offers a direct interface to the system PCI Express bus. This avoids the overhead and extra latency of the USB protocol. An “eGPU” ExpressCard to PCIe adapter is required to plug in a real graphics card and I got the $50 EXP GDC.
I settled on a Nvidia GTX 1050ti graphics card since it’s reasonably fast and power efficient. Note that a 220W Dell power brick is also required to power the PCIe dock and graphics card.
Recent Nvidia driver versions have introduced an incompatibility with eGPU setups and I spent some time troubleshooting “Error 43” before getting output on the external screen. I never got recent drivers to work, but version 375.70 from 2016 is stable for me—implausibly since it predates and is not supposed to support the 1050-series GPU. The old driver has proven to be a problem only when trying to play very recent games, and is not a blocker (but do get in touch if you happen to have gotten a setup like this working with the latest Nvidia drivers). I also tried a Radeon RX 560. While it didn’t require old drivers to work, it had all sorts of other display-artifact problems that I didn’t feel like troubleshooting.
The standard ZOTAC fans are loud and I replaced them with a single 80mm Noctua fan mounted with zip-ties. The fan connector is not the right one but can be jammed onto the graphics card fan header and wedged under the cooler. I removed the W520 keyboard and zip-tied another USB powered92mm fan to the CPU cooler so that the (louder) built-in fan doesn’t have to spin up as frequently (not in picture below).
The final upgrade was two 512GB Samsung Evo 860 SSDs that replaced the old 120GB Patriot ones to get me 1TB of local storage.
Computer on pegboard
The whole assemblage (gutted laptop festooned with adapters, the PCIe dock with graphics card, power bricks) is mounted on the wall under my desk. After much experimentation the components are now zip-tied to an IKEA SKÅDIS pegboard. The pegboard comes with stand-off wall mounts which allows some of the many cables to run behind the board. I put a small fridge magnet on the screen bezel where the “lid closed” sensor sits to keep the built-in LCD screen off.
I’m still very happy with the W520, and while I’m not sure getting the eGPU setup working was economical in terms of time invested (over just buying parts for a proper desktop), it was a fun project. To my amazement, it merrily runs slightly dated games like XCOM 2 and Homeworld 2 Remastered in full, glorious 4K.
Lenovo still supports the platform and recently released BIOS updates to address the Meltdown/Spectre exploits.
With the RAID 0 SSD disk system, the quad-core W520 still feels deadly fast and is a joy to use. It boots instantaneously and restoring a Chrome session with stupid many tabs (something I’m bad about) is quick. With 32GB of RAM I can run Docker for Windows and a handful of VMs without worry.
