| Electronics > Projects, Designs, and Technical Stuff |
| Control a servo from a potentiometer, WITHOUT a microcontroller? |
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| I wanted a rude username:
You may have heard of code golf, which is trying to solve a problem in the fewest lines of code. Using a microcontroller to read a potentiometer and PWM a servo accordingly is a favourite Arduino task, and can probably be done in a few lines of code. But can it be done in zero lines of code? Is there a non-microcontroller solution to this problem? I have one in mind, but it uses a bunch of discrete components. Presenting electronics golf: solve this problem to minimise Σ(electronic components, lines of code)! |
| oPossum:
Something other than this? https://www.google.com/search?q=555+servo+tester |
| I wanted a rude username:
Yeah, I have a hunch it can be done with fewer parts, but lack the electronics background to improve on that solution. Also it's an interesting exercise. |
| ebclr:
74HC14 1 capacitor, 2 resistors, 2 diodes, the pot is everything you need, to make a variable duty cycle oscillator, who will drive the servo position |
| Ian.M:
That's more complex (and has more pins to solder) than a CMOS 555 (so you can gamble on no decoupling) + a resistor , a capacitor, a pot and a diode. Add an extra resistor in series with the pot to limit the minimum pulse width. It can't really be simplified any further in the analog electronic domain - you need two RC time constants to set the timing so that's four components straight off, even if you cheat and use a mechanical stop for the pot knob to set the minimum pulse width. An electromechanical solution could be simpler - imagine a tiny bimetallic strip with a heating element wrapped round it and a pair of NC contacts as a thermal oscillator controlled by a set-screw bending the base of the strip towards the fixed contact to increas the on time. Tap off the output across the heating element. :-DD |
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