November 7, 2012
about 2 years ago
There are some useful suggestions for use, along with a link to a working project on the page for the linearly tapered version of this product:
about 2 years ago
I’m sorry to hear that happened. Not trying to be rude here, but why did you run a live current through the terminals without knowing what they are? There are no wires or connectors from the motor terminals to the rest of the device, so it’s pretty obvious it’s just a simple DC motor. You just use an H-bridge to set which of the two motor terminals is GND, and which is Vss (ie: +6V in my case).
Also, if you have a simple/cheap digital multi-meter, it is very easy to determine all 6 terminals of the two pots. If the resistance is infinite/open-circuit, it means the two terminals are not part of the same trim-pot. If the resistance is 10k-ohms, as noted in the electrical parameter datasheet provided, you know you’ve found the extreme connections (ie: terminals 1 and 3) for a single trimpot. If the resistance is on [0,10] k-ohms, and changes as you slide the trimmer, you know you’ve found the centre-tap.
Also, all may not be lost. It’s possible you’ve only fried one of the two trimpots, not both :)
If you still have a single working trimmer, just keep this in mind:
1) You need an H-bridge to control the motor, and have it move back AND forth. The L293D (digikey part: 497-2936-5-ND) is perfect for this, and it has all the clamping diodes built into the chip, so you don’t have to wire 8 external diodes. Well worth the two bucks per chip.
2) If you want to play with the speed of the motor, the easiest way would be to use a pulse width modulated (PWM) signal from your processor (eg: Arduino) to the signal being sent to the H-bridge. I use this for basic motor speed control, and it also works when using a multi-color LED to control the ratio of power for each of the red/green/blue LED components.
3) You’ll need an analog-to-digital converter (ADC) to read one of the two trimpots (the center tap). I wired the extreme taps to 0V (GND) and to Vss (+6V). Since it’s a 10k-ohm trimmer, not much current will flow, so this won’t fry the trimmer.
I replicated their pong experiment, and the device worked like a charm with the help of some MakerBeam bearings and beams.
No public wish lists :(
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