61–70 of 199 posts
https://aseq.substack.com/p/inside-the-lucira-check-it-covid
They include an STM32, but the instrument is performing an Isothermal PCR molecular test which makes the inclusion of a microcontroller a requirement.
Obviously throwing out electronics like this seems quite wasteful. But overall our society is fairly wasteful when it comes to disposable electronics.
This is depressing. Single use disposable. Full of copper, gold, tungsten, halfnium. Will leach poison into the ground. Some of the most advanced technology of our age. Use it once, toss it in the trash. Meanwhile the paper versions work just fine.
The optics on this seem to indicate that it is just a lateral flow test of some kind. It's not even different. Instead of having to interpret a couple lines you have software interpret the strip and tell you over bt on your phone. So much tech for so little.
https://aseq.substack.com/p/inside-the-lucira-check-it-covid
Nordic is not really that cheap if you just want a Cortex-M4. You buy Nordic parts for their radios. If you just want processing power, GigaDevices has an M4 at less than $1 last I checked. Unfortunately, it wouldn't work for the design we were working on as the standby power consumption wasn't great.
If you want bargain basement processors with connectivity, Qualcomm is still selling many of the old CSR chips. The low end chips went for <$0.50 in volume and the power consumption was often barely worth measuring. We used to chuck them into products every time every time I lost an argument with the hardware team about whether 10-15 cents of BOM cost is worth 3 months of painful bringup.
I worked at a company that was using these chips to control doors. They're extremely cheap chips, but writing code for them is not pleasant. Documentation is lacking and the tools people use to write code for it suck. Props to the devs who helped put this together.
> Documentation is lacking and the tools people use to write code for it suck. Okay, I'm going to ask "Compared to whom?" Nordic has been one of the better BLE chip manufacturers in terms of documentation, in my experience. Most places use Keil tools directly from ARM. So, if programming these sucks, so does programming most embedded Cortex M4 chips. (No argument. Keil sucks. However, that doesn't mean that Nordic su…
Earlier quoted context omitted.
If you read the full Twitter thread they explain that paper doesn’t work for everyone (the color blind and the incompetent, for example.) There is a use case, it just might not be for you.
The Abbott test has two lines separated… if two then positive, if one then negative. You don’t even need to tell the colors apart.
Earlier quoted context omitted.
The Abbott test has two lines separated… if two then positive, if one then negative. You don’t even need to tell the colors apart.
You do, however, need color vision to tell that the control line changed from blue to red (which the instructions tell you to do to verify that the test is working correctly)
Seems like you could just about accomplish the same thing with a pair of NFC tokens, a photodiode, and some transistors. Basic components. Connect one of the two NFC chips to the coil depending on how much light is reflected off the test strip. When you scanned it with your phone the activated NFC chip would respond with a URL containing a unique ID which could be interpreted by the manufacturer.
The Lucira test is in my opinion a bit more interesting: https://aseq.substack.com/p/inside-the-lucira-check-it-covid They include an STM32, but the instrument is performing an Isothermal PCR molecular test which makes the inclusion of a microcontroller a requirement. Obviously throwing out electronics like this seems quite wasteful. But overall our society is fairly wasteful when it comes to disposable electronics.
Earlier quoted context omitted.
The Abbott test has two lines separated… if two then positive, if one then negative. You don’t even need to tell the colors apart.
You do, however, need color vision to tell that the control line changed from blue to red (which the instructions tell you to do to verify that the test is working correctly)