While developing the device software for 454 Bio’s DNA sequencer, I needed to be able to build rpicam-apps and our HAL. While I could compile directly on the Pi 4 it was running on, it was quite slow:

aarmea@raspberrypi:~/Code/tirf-hal/builddir $ meson compile --clean && time meson compile
Cleaning... 0 files.
[70/70] Linking target apps/capture-service
    
real    4m12.382s
user    14m38.012s
sys     1m8.128s

Instead, I set up my much faster M1 Mac to cross-compile this and our custom code, which is almost 10x faster and allowed me to iterate much more quickly:¹

debian@debian:~/Code/454-hal/builddir$ meson compile --clean && time meson compile
Cleaning... 0 files.
[70/70] Linking target apps/capture-service

real    0m32.847s
user    1m46.109s
sys     0m14.082s

Because the environment is virtualized, it was much easier to set up and integrate Pi-specific libraries than with other cross-compilation toolchains.

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Many scientific and artistic camera applications require precise exposure timing, such as when capturing the stroboscopic effect, performing stereo depth mapping, or imaging with TIRF microscopy¹. This can be achieved even with the Raspberry Pi HQ camera, though it took some work and reverse engineering to get there.

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I had been thinking about upgrading the thermostats for a while, and I honestly thought it would be simple. I was very wrong: I ended up having to replace the zone controller and a power transformer as well, and it took me over a year to finish the job.

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I implemented a way to automatically create Bluetooth Classic sockets between two nearby Android devices running the same app. This method works continuously in the background without wakelocks, and it does not require pairing, root, or any user interaction.

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I was looking for a white elephant gift, and the silliness of this animatronic Christmas tree was too hard to pass up. The humor wore off after the third time I heard it sing, so I decided to make it useful by adding Alexa.

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I found and ordered ELP’s stereo camera to calculate depth maps with OpenCV and see what I could do with them. It turns out that just getting a decent depth map was much more involved than I expected. Read and download my code here.

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I wrote a Hugo “theme” that loads its pages asynchronously. Play with it here or read the code here.

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My older posts are still available at http://blog.albertarmea.com/.

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