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There's an ARM Cortex-M4 with Bluetooth inside a Covid test kit

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Re: There's an ARM Cortex-M4 with Bluetooth inside a Covid test kit

#141

Post by rurban »

DoingIsLearning wrote: post #90
rurban wrote: post #50

Earlier quoted context omitted.

I write baremetal fw for those chips. No debugger, extremely bad stdlib which I rewrote, no qemu. Horrible modem interface. But still much more pleasent than Linux FW or raspi's. They are cheap, last 10 years with a single battery, and do only what they need to do. Also secure. No crazy attack vectors. And easily symbolically verifiable. And I wrote tons of simulators and fuzzers for them.

Let me flip this around, I am looking for ways to improve testing, specially now that I am mostly remote. In your experience, what targets have a stress-free experience with qemu emulation?

Working on it in my github rurban/qemu-stm32 fork. Checkout supported platforms for qemu and better renode. There you also have debugging interfaces.

Stressfree qemu support was only for my even smaller avr targets, the 1281. But AVR is crazy compared to the Cortex-M4. We switched to arm completely, no avr's anymore. Anyway, no need for qemu or other emulators, when you can easily write simulators. You just throw in some mmaps, the simulated libc, the UART, and networking. Much better than emulators.

Re: There's an ARM Cortex-M4 with Bluetooth inside a Covid test kit

#142

Post by johannes1234321 »

mrunkel wrote: post #120
AlexanderDhoore wrote: post #116

As a European: why are there chips in this? I just broke open mine and it looks like this: https://imgur.com/a/muz7FIy I bought 50 of these 2 weeks ago. Were 3-4 euro a piece.

It’s for the Bluetooth piece. The optical sensor reads the result and the turns on the light and/or lets the phone know over Bluetooth. Seems unnecessary, but if people want to buy it…

> Seems unnecessary, but if people want to buy it…

Considering that this is an article used once for a few minutes the environmental cost for production and deposition is high and society shouldn't tolerate ...

Re: There's an ARM Cortex-M4 with Bluetooth inside a Covid test kit

#143

Post by tssva »

throwaway4good wrote: post #100
throwaway4good wrote: post #85

Earlier quoted context omitted.

In Europe a COVID19 quick test is 1-2 USD. This is 20-40 USD? For a device you only use once. Why is there any kind of market for this?

Is it because it is covered by health insurance? Might as well get the expensive one if I get it reimbursed ...

Home COVID tests are not generally covered by health insurance.

Re: There's an ARM Cortex-M4 with Bluetooth inside a Covid test kit

#145

Post by throwaway4good »

Nitrolo wrote: post #134
AlexanderDhoore wrote: post #116

As a European: why are there chips in this? I just broke open mine and it looks like this: https://imgur.com/a/muz7FIy I bought 50 of these 2 weeks ago. Were 3-4 euro a piece.

I'm wondering if they're subsidized, but the price in Germany at the supermarket hovers around 1€ each. I was really surprised to hear that these are not a thing in the US, any idea why?

Because the ones you get in Europe are made in China.

Re: There's an ARM Cortex-M4 with Bluetooth inside a Covid test kit

#146

Post by amelius »

new299 wrote: post #61

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.

> They include an STM32

This might explain partly why they are all sold out :(

Re: There's an ARM Cortex-M4 with Bluetooth inside a Covid test kit

#147

Post by tssva »

distances wrote: post #88
ip26 wrote: post #22

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.

> Will leach poison into the ground. Electronics must not be disposed with general waste, I'd imagine all Western municipalities have special recycling programs for electrical devices. Not sure if they'd be that happy to receive used covid test kits though.

About 42% of e-waste is recycled in the EU and about 15% in the US. Even those numbers don't reflect reality since a large percentage of "recycled e-waste" is shipped off to poor countries where it may or may not be strip of some parts before being dumped.

Re: There's an ARM Cortex-M4 with Bluetooth inside a Covid test kit

#148

Post by roeles »

londons_explore wrote: post #125
roeles wrote: post #81

For those interested: I ported FreeRTOS 9 to an nRF52840 in my previous job. This family used a lot. It's in my Tado smart radiator knobs, in the AirTags. I can only compare it to FreeScale chips, but one thing that pleasantly surprised me is the flexibility in pin-assignment. Instead of the pin-mux that we'd have to do on the MK24, I could just assign pins during usb/i2c init without any limitations. The SDK is quit…

An any-to-any IO multiplexer turns out to be pretty large in silicon area. You're paying extra for that feature as opposed to devices where each pin has a choice of just say 3 functions. For most users, they prefer to have the chips cheaper and spend an extra few minutes of engineer time figuring out which pins need to be hooked up to what. I can see for smaller volume devices where engineer time dominates, and devic…

Thanks for the insight! I didn't choose the nRF, it was a given. I believe it was chosen due to being similar to the MK24 (also an M4) and having Bluetooth. The chips ended going into wearables, and BTLE was seen as the way to configure/upgrade the devices.

Re: There's an ARM Cortex-M4 with Bluetooth inside a Covid test kit

#149

Post by patricktlo »

rurban wrote: post #141
DoingIsLearning wrote: post #90

Earlier quoted context omitted.

Let me flip this around, I am looking for ways to improve testing, specially now that I am mostly remote. In your experience, what targets have a stress-free experience with qemu emulation?

Working on it in my github rurban/qemu-stm32 fork. Checkout supported platforms for qemu and better renode. There you also have debugging interfaces. Stressfree qemu support was only for my even smaller avr targets, the 1281. But AVR is crazy compared to the Cortex-M4. We switched to arm completely, no avr's anymore. Anyway, no need for qemu or other emulators, when you can easily write simulators. You just throw in…

Your simulations sound super interesting, I'd love to read more if you're willing to write about it!
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