input devices
This week's assignment was to measure something off a sensor on a board we designed.
The sensor I'm using is a phototransistor, which is a light sensor. A phototransistor is, get this, a transistor where the current going from the emitter to the collector is dependent on the level of incoming light the sensor receives.
Before getting into making the week's assignment, I decided that I needed a serial to USB converter, so I made the FabFTDI board. This way, I no longer have to be in the shop to program the boards.
Good things that I learned from making that board is that for USB purposes with that microcontroller (ATmega16U2) you need either 8MHz or 16MHz external crystal resonator. The internal 8MHz resonator isn't accurate enough for high-speed USB. We didn't have a surface mount 16MHz crystal, so I soldered on a non-surface mount component, which looks kind of comically large.
Aside from that, I made 3-ish boards this week.
The first board was a I'm-not-in-the-shop-but-I-have-a-phototransistor-let's-see-if-this-works board. I have a board from a few weeks ago that is non-functional because I accidentally ripped up a bunch of the traces. So, I removed some parts from it, added in wires, and wired up what is basically this board . I then loaded up Neil's light reflection synchronous detection hello world program.
The next board I made was actually designed. It has two phototransistors and an LED. I also milled the already existing phototransistor board design, in case this one didn't work.
But, both the boards work, sort of. I can read something in from the phototransistors and then based off that value get the LED to do something, but I haven't been able to just get a serial display of the values coming off of the phototransistors yet :(