Upcoming projects

There are a few projects that are still at varying stages of progress and will probably be documented and put online given enough interest (hint hint). They are;

  • A 60W DC-DC flyback converter, 9-15 V in, 0 - 200V out, approximately 80-90% efficient.
  • A modular MOSFET-based coilgun stage for low to moderate power (a few joules of kinetic energy, enough to sting but not bruise).
  • A simple multi-point temperature sensor board using the DS18B20/DS18S20 sensor.
  • A capacitive rotary-encoder-like unit, with an RGB led for status. (Think touchpad or 2nd gen. Ipod)
  • NEW a brushed DC servo motor controller (DC motor with incremental rotary encoder), up to 25A and 40V continuous load. Will be finished some time during the summer of 2013.

(This is a continuously updated list)

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3 Responses to Upcoming projects

  1. Christofarrow says:

    Would love to look at the coilgun stage...

    • jonathan says:

      At the moment I don't have much written about the coilgun stage; it's a relatively standard hard-switched MOSFET-based coilgun driver. The same PCB is used for both the primary stage as well as secondary/tetriary/n'th stages, where solder bridges configure the the functionality. The flyback converter mentioned in the bullet points is used to drive the coilgun stage, which works best at around 100-200VDC (with some, though unfinished, documentation available). Here's an image of both parts; http://wstaw.org/m/2013/08/30/small.jpg with the coilgun stage to the left and the flyback converter to the right.
      I've placed everything I've got related to both projects here; http://www.rabidmantis.se/?attachment_id=164. Keep in mind this is far from finished, but as the coilgun stage is pretty simple the schematic should be more or less "self-documenting" ;)

      • jonathan says:

        Oh, and to clarify, use the "unified" coilgun schematic/board files. The primary stage (triggered by a debounce'd pushbutton) has a single potentiometer to control the on-time of the stage --- I used an LED/photodiode pair to measure the occlusion time when the projectile passes to adjust the potentiometer for minimum time. Be sure to monitor the peak current and turn-off current through the switch MOSFET and ensure that the peak current and avalanche energy doesn't exceed the absolute maximum ratings in the datasheet ;) (Control this by changing the charge voltage to the capacitors and the number of turns on the output coil).
        For the secondary stages there are two potentiometers, one that adjusts a variable delay from a trigger caused by the projectile passing an LED/photodiode pair, and one that controls the on-time. Adjusting these is a little trickier; I found that adjusting one for maximum velocity, and then adjusting the other, and then going back and forth between the two gave good results!

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