Will This Stop A Servo From Draining Power? HELP!

Projects General Guidance
1

Thanks so much for any help. I'm using a continuous servo and a Arudino nano. The continuous servo will rotate in a random direction for a couple of seconds, then stop for 15 to 45 seconds, then start moving again. This is easy with a power supply but I need to do it with batteries.

I realized that when the servo is not moving, it's still being powered (to hold that position) and therefore is using power. I know if I cut power to the servo, it'll be able to be rotated but it's lifting a really light load so I'm not worried about that.

If I use a transistor to turn on and off the grounding of the servo while it's not turning, is this a smart way to prevent the servo from using power? I've seen people do this same thing with relays but I'm not familiar with relays and I'd much prefer to use a transistor.

I've attached a diagram below of how I'd do it. I'd like to use a TIP122 transistor instead of a MOSFET because I've got a bunch of spare TIP122 and according to my multi-meter, the continuous servo doesn't draw more than 0.5 amps.

Does anyone know if this is smart/will even work?

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2

A continuous rotation servo which is not moving (and not blocked by an object) is drawing no power or very low power.

Maybe it is time to buy a more advanced multimeter which can measure current.

3

Ah perfect, thank you! Sadly it's not my multi-meter, it's the person running it. I'd only set up this diagram on paper and in my head and was thinking for some reason that the servo would take a lot of power while holding still, even though I knew it was going to have a light load. :confused:

Anyways, thanks a ton!

4

You should ask for a multimeter for your next birthday. It is an essesntial tool for this kind of work or hobby.

$5 (USD) will buy one that does 98% of what you need for Arduino work. The remaining 2% is current measurement such as this particular case.

5

Thanks! I actually have a multi-meter, I was just being stupid and not using it. My continuous servos I don't come until tomorrow so I was trying to set the circuit up on paper without using my multi-meter and just wasn't thinking about it correctly.