RASM

Raspberry pi -> Arduino -> Stepper Motors (library to controll the hardware stack)

Goal

The goal of this repository is it to create a simple plotter - along the lines of Der Kritzler.

status (march 29th 2013)

I just set up the github repository, so for now I will more or less randomly push code into the repository and only over time create a documentation etc. So if you have questions just write me MarcoPashkov AT gmail DOT com.

Hardware

• Raspberry Pi (thank you PyCon 2013 for this AWESOME gift!!!)
• Arduino Uno
• 1 x Adafruit Motor/Stepper/Servo Shield for Arduino kit (v1.2) [ID:81]
• 2 x Stepper motor - 200 steps/rev, 12V 350mA [ID:324]
• 2 x Aluminum GT2 Timing Pulley - 6mm Belt - 36 Tooth - 5mm Bore [ID:1253]
• & lots of cables

Communication

The raspberry pi talks via USB to the arduino on a serial connection. At this point all that the arduino understands are simple messages explicetly for the stepper motors. Since I wanted to get a working prototype fast I wrote as little code as possible to get everything working.

• message format: motor,speed,steps,direction,step-style;
• e.g.: 1,100,50,1,1;
• motor 1 moves 50 steps with speed 100 "forward" in "single"-style.

values:

• motor: 1,2
• speed: 1 - 250 (for me - above that my arduino has power-issues - might have to put a direct power supply in for the motor shield)
• steps: 1 - ∞
• direction: 1(forward), 2(backward)
• step-style: 1 (single), 2 (double), 3 (interleave), 4 (microsteps)

top layer

Using pyserial, flask and processing.js I want to build a small webserver that accepts vertor images and then directs the stepper motors to draw the image.

Software Requirements

• flask
• pyserial
• gunicorn

How to start the server(of course with the correct raspberry pi IP-address/port):

cd ~/rasm/raspberrypi/
gunicorn server:app --bind 192.168.1.8:8000 --workers 2