Soon after my last post at a routine eye exam, they found a minor issue, however it has meant that I have needed eye drops in the interim. Soldering small SMD packages with one eye dilated was challenging.

I got past that, and have been working the tracker firmware. Initially the device would not program, I think this is due to the opamp output holding the pin at the wrong level, I solved the issue by lifting the opamp pins in question.I don't know if this has broken the board by lifting the pads too, but it does now program consistently.

I also had a strange experience with the main controller it (literally) smoked 2 of the ESP modules, and then the micro refused to program. I have a suspicion that a stray PSU connection managed to get 12v into something important. Fortunately I ordered several spare sets of parts for this device so I could easily populate one of the "spare" boards.

As part of this effort I finally got around to buying a "real" logic analyzer, I got one of the 16 port Saleae clone devices, it makes all the difference to be able to see the data on the SPI bus! On the tracker I am using a NRF24l01 for communication with the main controller, as well as an MPU6500 accelerometer, both on the SPI bus. Having the logic analyzer to see the communications to these devices made setting them up incredibly easy. I would say that after a decent voltmeter, and an O'scope, the logic analyzer is an important tool in your bag.