Control from Raspberry Pi?

[laird]

I am wondering whether it would be possible to control the Peachy with a Raspberry Pi. Given that resin-based printing is quite time consuming, I'd rather not tie up a computer controlling the Peachy. So what I'm thinking is to use Octoprint to drive the Peachy. Octoprint is a web server that runs on the Pi that you can upload STL files to, it slices them, and sends them to the printer. Or you can slice the geometry on your regular computer, and send the resulting file (gcode) to Octoprint to send to the printer. And it can show printing progress, a webcam, etc., all on the web page. It's all open source, so the "work" would be to get the Peach slicer and printer control software to run on the Raspberry Pi. Of course, the Pi is a pretty limited computer, but it has a headphone jack so perhaps it can control the Peachy. It doesn't have a microphone input, but it has a bunch of general purpose IO pins that could be wired up to detect drips (or control them, etc.).

So, what do you guys think? Possible?

[Slatye]

The Raspberry Pi doesn't have any analogue inputs, so you'd need a separate board for that (or just a USB soundcard that does have a microphone input).

I suspect that Octoprint wouldn't work for this one. The Peachy requires very different control signals (ie an analogue waveform rather than G-code). The Peachy software is designed to work through Blender, and Blender does not work with the Raspberry Pi.


With that said, I can see three possible alternatives:

(1) Have some G-code equivalent format. Instead of lots of explicit commands, it'd be an analogue waveform combined with an index that tells it what the Z level should be at each time. That would be generated on a desktop PC (at many times realtime speed) and then copied to the Raspberry Pi. A fairly simple bit of software on the Raspberry Pi could play the waveform, at whatever speed is required to keep up with the Z level movement.

(2) Use a different micro-PC. In particular, Intel's Galileo is a more-or-less Arduino formfactor, but it's an x86 chip and it's got enough RAM (256MB) to run a headless copy of Linux. It's not going to be very fast, but it might be adequate.

(3) Just grab an old laptop on eBay for $50 and use that. Even an old EeePC should work fine for this sort of thing, while taking up hardly any space and using hardly any power.

[rylangrayston]

Ok so we have driven the mirrors with a r pie , it works but not well. Our r pi is a very early version, and has very very week audio, i here that the audio has been completely re worked in newer versions but we haven't tested those.

The Peachy requires very different control signals (ie an analogue waveform rather than G-code). The Peachy software is designed to work through Blender, and Blender does not work with the Raspberry Pi.

Actually to keep in the spirit of working with other open projects we have left g-code in our tool chain, We have a script called gcode_to_wav_converter.py
Altho we are focused on getting the printer to run with blender, the way we are doing this is open to other programs running the peachy printer also.
We are writing an api for any program to send jobs to the peachy printer via g-code, blender is just the program we are choosing to get working first.
to get blender working we basically need to add slicing and gcode out put to blender, and that is well under way here: http://blenderartists.org/forum/show...86#post2520986
blender dose not work on the r pi because the r pi dosent have open-gl but there is no reason that gcode_to_wav_converter.py cant run on the r pi. although it might be slow, hopefully we can get it to stream gcode to audio and hopefully it can do that faster than the printer can print! even on an r pi.

I wonder if the r pi can read the gpio fast enough to catch a drip ? my guess would be that it can.
and im sure that with a transistor or 2 we can get a drip to cause a full 0 - 5 volt swing that can be poled by on of the inputs of the gpio r pi pins.

So all that said i think what you want to do is quite possible!
Be sure to post your findings here many many people will benefit!

PS

We are in contact with Octoprint and they like this idea too