Monthly Archives: April 2011

Building Reprap Prusa

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I’m building a Reprap Prusa. This is a Reprap version which is cheaper to build. It was easy to print and easy to build. PLA bearings seem to work ok. It’s not done, so I haven’t actually printed anything real yet, but the controller is working, moving the parts around. The parts are:

  • Plastic parts printed on my Thing-o-matic.
  • Motors from Zapp Automation.
  • Gen7 Electronics. Bought a kit from “Traumflug” (Markus Hitter). Seems to work well so far. Running teacup firmware at the moment. Thanks to “Traumflug” for good support and help.
  • Smooth bars are aluminium rods from Maxbo. The steel ones were much more expensive. Aluminium cost a few dollars per meter. Not sure if they are good enough, but seems ok. I sanded them with very fine sand paper to make them smoother, and the parts move very smoothly.
  • Timing belts and lots of other minor stuff from Elfa. The timing belt was  a 10mm wide belt, split in half.
  • Extruder… not done yet. Trying to make my own.
  • Software. For the thing-o-matic I’m using ReplicatorG, which I really like. I haven’t found something as stable and solid for a Mendel yet. Tried the reprap software and repstrapper, but I’m not really happy.

MSP430 Launchpad RF based motor controller

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There’s this kid who wants to control a tank from his standard remote control, but it’s been difficult to find the right parts at the right price, so I made a component for him.

It’s basically a motor controller, powered by an MSP430 that takes PWM input from a standard remote control’s receiver. It can drive back and forward. It’s based on the cheap value line MSP430 that comes with the Launchpad.

It receives the two PWM signals from a standard RF receiver, takes the time of the PWM pulse the receiver sends (typically to a servo), calculates whether it should be moving the motor forward or backward, generates two new PWM signals and control signals for a cheap motor controller called L293D to drive the two motors of the tank. It can go backward and forward. I’ve made code examples that uses two sticks, one for each motor, and one that has a more traditional left, right, forward, backward control. The MSP430 code is posted below. Feel free to use the code as you wish. Give me credit if appropriate.

 

 

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