Problems with Raspberry Pi
This post is mainly to see if others are seeing similr problems - I'm going to be testing more to try to fix the problems below. I'm very familiar with Linux, use the Pi a lot and am programming stm32f4 devices as part of my work, so
I've started with the image at: https://cdn.robotical.io/public/raspberry-pi-img/robotical-pi.17.07.img.gz
I tried this with an older Pi with fill size SD, but it wouldn't fit in Marty - the micro SD ones is fine. For this reason I've not tried the oldest Pi versions, but I probably will later.
I then tried a Pi B 1.2, and this failed to boot (a kernel panic displayed when attached to a screen. I tried a second, better micro SD, and this also didn't boot. I've borrowed a Pi 3 and that boots fine, so it seems the image is only for Pi 3.
However there are a few more problems.
The image doesn't recognise the wifi, but it's running as an access point, so presumably hostapd has it in use. I'll have a bit of time to check this in the week; I've used hostapd quite often so I don't expect that to be too hard to fix. I'm using standard ethernet to debug. so for now the Pi is mounted externally with the link cable through the mouth.
The next problem is Marty not always being found; roslaunch ros_marty startup.launch seems to only work part of the time. I'm running plugged in, so power should be ok (but see below), and I'm investigating further.
Another more problematic issue is occasional episodes of marty throwing a fit - fast random motor movements until turned off (I don't wait for long to avoid damage). This only happens with the Pi attached, and while trying to set up wifi while connected via ssh over ethernet. I did wonder if the problem might be if the 5v gets drained a bit too much, as I know the ethernet connection does cause a surge in power usage when it starts up. I'll try to monitor the 5v line - I've got an stm32f4 board I've programmed that I can use to do that. Low voltage could also possibly explain unexpected movement.