• Movement success!

    3 days ago • 0 comments https://instagram.com/p/6yzLU6IfNx/?taken-by=imakerobots
    It's very early days, but I've got great big news: I have now got controlled movement on all five axies.
    Most of the day was spent testing electrical connections to my sensors and getting them to reliably deliver meaningful data from all five axies at once.
    https://instagram.com/p/6yLZLuofPC/?taken-by=imakerobots
    I also reprinted several pieces to correct for printer ...drift? I ask for a 6mm hole, I get a 5.7mm hole.
    https://instagram.com/p/6vAFGjofBY/?taken-by=imakerobots
    Same goes for pegs - usually oversized.
    https://instagram.com/p/6xiBxsIfMA/?taken-by=imakerobots
    After dinner I meant to play Rock Smith but, obsessive that I am, I went back to the robot and started implementing my first PID loop.
    Since the sensors are delivering data all the time, I call gcode M114 to get the current sensor values. Then I call G0 [A/B/C/D/E][angle] and the PID loop kicks in to move that motor or actuator until the sensor value matches the target value.
    Most of the first hour after that was spent hovering nervously over the e-stop while I unscrambled (in software) the motor/sensor relationship. Several times I said "go left" and the motor in question went right. ESTOP ESTOP ESTOP! One time the piston lifted the front end of the arm off the table. I wish the wrist were that strong!
    The sensor magnets are really Goldilocks. For example, if the arm moves far enough back then weight compresses the anchor sensor downwards until the magnet is too close (papa bear). I imagine if I make the arm stretch out too far the opposite will happen (mama bear). I want it to stay baby bear all the time.
    The next couple of days I'm waiting for my custom PCB to arrive. The time will be invested finishing an article for MAKE magazine and tweaking code in the Makelangelo

    I asked HAD.IO to work on instagram integration. They say they're working on it.

  • 3d printing test fits

    3 days ago • 0 comments https://instagram.com/p/6vAFGjofBY/?taken-by=imakerobots
    https://instagram.com/p/6xiBxsIfMA/?taken-by=imakerobots
    Nothing sucks like printing part that has to be sanded to make it fit.
    Over the weekend I printed several pegs and holes of graduated sizes to find the right fits. Then I went back and adjusted my 3D models with the new tolerances. That really bothers me - do I bake the tolerances into the original model? Maintain a version with ideal+correction? Both solutions are ugly.