July Workshop

[muonide]

That was a great meeting, all.  Y'all deserve some rest, for sure. 

I've been looking through a bunch of the code and am finding little bits I think I can help with.  

First order being servo control on the Still & Video payloads.  I still need to take a look at the occams board there, but looks like one just needs a little i2c pwm chip like a DRV8830 for the servo connected to occams. I don't reckon the Pi's pwm is stable enough for the video camera (maybe wrong there, haven't used servos w/ Pi yet); stills would probably be alright.  Modifying the python code looks straightforward enough. I'm thinking maybe adding one more slider to the GUI for camera servo position and piggyback that onto the update camera settings command. I'll probably soon take a stab at making a pcb with a realtime clock and pwm instead of the little clock board in the kit.

Thoughts?

[Skylar MSGC]

So there definitely room for improvement on the servo idea that we gave to everyone.  We didn't include any code for control on the pi side. This was because it was a idea that got tossed at me one day at near the beginning of June.  I completed a script in python to run and control the servos using a pwm on the PI and have tested it out in the field to make sure it worked.  Currently I connect to it by creating a ssh connection to use  it but there are other methods to approach.

Your concern with the Pi is valid since the Pi doesn't have a real time operating system.  Which means the PWM that comes from the Pi could be a little off, which for a high precision servo I wouldn't recommend using the Pi but the servo that we gave you is a high torque low precision cheap servo.  So using the Pi probably wouldn't be a problem.  I'll have to post what I came up with to the github account sometime today (7/21/2016).


github.com/MSU-BOREALIS

This github account has all the code for the ground station and payloads that we had for the workshop.  You can download a zip file of the code you want or learn how to use git to be able to contribute a little easier in the future.


With adding the slider. I would say that would be pretty cool, being able to control the camera from the ground station in real time would be a pretty cool hands on event for students.  If you have any questions on how to possibly do it feel free to ask, one of the members may have a suggestion that causes you to get a great idea.

The traces on those boards are pretty easy to break if you wanted to high jack a few lines as well. We have one student that did that with the OCCAMS board to power a servo as well.  

[muonide]

I'm kinda glad y'all put that in towards the end. Gives me something fun to geek out on I'll try it the easy way with the Pi's pwm first then see if I need to get fancy with it. I've been using my x-carve for milling pcbs lately and will have an OtherMill ordered shortly, so making short batches of pcbs will be a cinch.