When I set out to do this I was expecting to make a new version of the badge with a different circuit originally I had to add a bunch of components just to make the amplifier work. But, I just kept optimizing and whittling it down and eventually ended up back with the original circuit. This badge is the same one I showed off six months ago. It’s unmodified there are no hardware changes at all. So in a sense, the ability to do wireless updates was there all along – we just had to unlock it, by thinking really hard about the problem.
I didn't realize this was the same creator of the tiny LED matrix earrings. I love the attention to detail in the work and the article. Super interesting!
Have you considered a positive feedback capacitor with the op-amp, to try to make an oscillator?
Then the illumination on your LED will affect the phase of the oscillator. By trying to make it oscillate at ~10Mhz, and then sampling the data, you should avoid the clipping problem, and you'd have a lot more data to use to potentially extract interesting things with clever math.
Even if the oscillator runs at 10Mhz, you don't have to sample at 10 Mhz - you could sample at a lower frequency (which must be clock cycle accurate) and make use of aliasing to still measure phase shifts very accurately.
You're totally going to measure the power supply, temperature, radio signals and a whole host of other things at the same time, but with the right signal processing/modulation you should be able to extract the effects you need.
Sorry I'm not mitxela, I just find pretty much all their projects old school hacker awesome.
Good suggestion but from their article it seems like there's some really odd silicon level interactions going on so who knows? Might be worth getting a CH32v003 and finding out!
I swear I remember reading somewhere, probably 10+ years ago, and probably in a MAKE magazine catalog, about projects that you could reprogram (POV displays and the like, text only) by holding up to your computer screen. I have no idea what the name was, but I'm pretty sure they used a photocell and nothing else, and communication was of course one way. I never bought one, but they seemed pretty cool.
This would likely have been the Mintronics POV kit (MAKE had a whole series of kits that shipped in an Altoids/mints tin, e.g. the Mintronics survival pack [1], which had a mini breadboard and 60+ components), here is a picture:
So it's cool regardless and I have to think that it has some benefits, but I have to ask... What's the benefit over pogo pins, especially for programming the chip? I guess less special hardware on the computer doing the programming?
There is no special hardware at all, which is a _huge_ deal.
This is especially important for consumer devices like badges.
Anyone can find a device with screen that can run a webpage, but very very few people would have a right programmer with right pogo pins.
Plus, pogo pins at less than .100" spacing are pretty fragile, and the projects author uses are so small they'll need a much finer pitch.
I'm not sure if it's useful in this incarnation, but I am reminded of the localizers in A Deepness in the Sky, an early description of smartdust which were relatively omnipresent and capable of communicating and being reprogrammed by light patterns.
When I set out to do this I was expecting to make a new version of the badge with a different circuit originally I had to add a bunch of components just to make the amplifier work. But, I just kept optimizing and whittling it down and eventually ended up back with the original circuit. This badge is the same one I showed off six months ago. It’s unmodified there are no hardware changes at all. So in a sense, the ability to do wireless updates was there all along – we just had to unlock it, by thinking really hard about the problem.