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Adjustable Motor Voltage

A project log for Nerdfeeder

Simple, inexpensive bird feeder that dispenses peanuts in exchange for dropping stuff in a hole.

Stephen ChaseyStephen Chasey 07/04/2022 at 10:201 Comment

Before I get into using power banks for this I need to boost the voltage a little, which will help me get more out of the D-cells anyways. The motor I'm using for the dispenser seems to struggle with quick dispensing once the battery voltage drops below 5.3 volts. I made a simple voltage booster with yet another 555 :) and an n-channel MOSFET that I think will keep the vibration dispenser working more reliably until the voltage gets below 4.5 (and the NE555s stop working). This would stretch the lifespan of alkaline batteries a bit and set the stage for me to experiment using a rechargable 5V 2.2A USB power bank instead.

I think this will also provide a little more flexibility on what motor you use, and let you crank up the RPMs a bit more for larger containers where the weight of the peanuts make the dispenser harder to vibrate.

I haven't added feedback with a comparitor yet - will try it out as-is and see what's needed.

Also adding a small shelf to a larger jar so the weight of the peanuts doesn't dampen the vibrations.

Discussions

Stephen Chasey wrote 07/04/2022 at 21:38 point

Voltage booster not helping as I'd hoped. I tested it on a couple similar motors with no load.  I could adjust the speed by changin the voltage betwen 6V and 10V. The motor in the machine does not seem to respond the same way - basically stays the same speed, and one slower than without it :(.  I'm probably making a simple mistake, so I'll continue to mess with it. 

I did add a shelf blocking about 2/3 or the jar about 2. cm above the dispenser assembly to take some pressure off from the nuts above so the things can vibrate more freely when the jar is full. That at least sems to be working, so I won't have to refil the peanuts as often.

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