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Powering Arduino and servos/motors with one supply

Helo, all

I tried to power Arduino (Duemilianove) and servos/motors it controlled with the same battery, but Arduino continuously restarted during the operation. Actually it was a surprise for me, since Arduino already has voltage regulator chip and filtering capacitors in the input circuits...

I solve this problem by supplying them with different batteries, but I don't like this solution. Could anyone help - how to provide single power supply?

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Good suggestions!

Just be aware that using the diode will drop the voltage to the regulator by 0.6 volts. Most regulators (7805) need at least a 2 volt overhead to function correctly. This could cause problems with a 7.2 volt battery pack.

If the power is dropping due to heavy loading or inappropriate batteries then Robologist idea is a good start.

It never hurts to put a large capacitor on the power supply.

Servos and motors can generate large amounts of electrical noise which could get past the basic filtering on the Arduino boards. put a 0.1uF monolithic capacitor across each servos power connections and if possible one directly across the power pins of the processor. Monolythic capacitors have a low ESR (equivalent series resistance) which allows them to respond better and faster than some other capacitors to spikes and surges.

The original caterpillar has 8 very noisy servos which originally created havoc with the processor and IR sensor. I used a monolithic cap on each device and across the servo power pins plus a large electrolytic capacitor directly across the servo power pins. (Use at least 470uF) 

This provided stable opperation. 

Hi Oddbot. I was trying ti understand; You conected 1 monolithic cap in series between the servo and arduino power pins? And about the electrolytic capacitor what does  directly across the servo power pins means?  Also its a 470uF with what voltage?

Regards

Try adding something like this to your set-up. Power the servos and motors off the battery side, and have the micro on the other side. Use something like a 1N5817 and a large 500- to 1000 uF electrolytic cap. You neglected to say what battery pack you were using, which would be helpful to know.

power-add-1.jpg