I had some home remodeling projects to do this weekend, so I haven’t had much chance to work on the spinner this weekend. I do have a couple thoughts to share about the project though.

1. I wish I had put more testpoints on the board. I had thought about that when doing the layout but couldn’t think what I should break out. I wish I had thought harder since the hall effect sensor was a clear choice. I’ve had problems with that on every single board I’ve made, so it would have made total sense to break that out. SPI would have been another easy choice since that’s how I communicate with the LED driver. But, since I put the ICSP header on there, I did actually have that broken out! That was probably just luck.
2. I had thought about putting a DC-DC boost converter on the board. That way I could have used a single AAA battery and boosted it to 5V. At the time I didn’t do that because I hadn’t designed or tested a boost converter and didn’t want to take the extra time to do that and because I calculated that it wouldn’t have saved me any money on the PCB printing. I thought about picking a different battery, but I didn’t know of a commonly available one that was smaller and provided any current capabilities.Now I wish that I had done that though. If I had boosted it to 5V, then I could have directly used my FTDI 5V USB serial cable. As it is now, to use that, I hook 5V on the ICSP header and turn off the battery when I’m using the serial port. It would have been way more convenient not to have to deal with that. My next design will incorporate a boost converter. Although, now that I think about it, I am having trouble with the LED driver pulling so much current that 2 AAA batteries have problems. I don’t know what would happen if I tried this with a single AAA and boost converter. I need to do some experiments…
3. It has worked out very well that I put the Arduino bootloader on the processor though. Makes it very easy to compile and upload–almost just like using a regular Arduino. The only reason it’s not the same is because my FTDI cable doesn’t break out the DTR signal that the Arduino software uses to reset the board. At the moment, I have to manually reset it for each upload and sometimes I get the timing wrong. But, it is still very handy to press the one “compile and upload” button and have it all happen! MUCH easier than back in the day when I was playing with 8051s and had to use a standalone EEPROM programmer and physically switch chips each time!

That’s all for now. More updates as soon as I figure out how to fix or workaround my current problems…