"Quick and dirty" question

Hi
I have 2 potensiometers setup as a servo system in a circuit with motors and delicate measurements. My question is how you would go about supplying the 2 potentiometers with 5V? As i see it, i can either give them 5V from the arduino or i can use a voltage regulator. Which of the possibilities would you use and why?
I am afraid that if i use the Arduino i might get a noise problem when drawing a fair bit of current (10-15Amps) in the motor.

If you can answer the above question, then i have one more.
Lets say a lot of current is drawn by the motor which is hooked up to the same power supply as the rest of the system (24V batt) this will produce some noise in the rest of the system right? i can try to keep this down by placing decoupling-capacitors on every IC i have (does that go for the Arduino itself as well?) and hereby reducing the noise. But what i am not sure about is how much ripple would be seen if i placed a 5V voltage regulator in the system, when fluctuations occur because of the motors drawing current.

The diagram of my system is attached - feel free to comment :wink:

Cheers

Use 5V from the Arduino, they need very little current - 10K pot will draw just 0.5mA.
Use 3-conducter (+5, Gnd, Signal) shielded wire, with the shield itself grounded on just one end.
Decoupling caps would be good - 24V into a 7805 might be pushing it, on the other hand you are not drawing much 5V current.

Personally, I would use a dc-dc switching module, such as V7805 for the Arduino & pots. Use CrossRoads decoupling for noise elimination.

http://www.cui.com/product/power/dc-dc-converters/non-isolated/1-a-output-current/v78-1000r-series

Ray

Thank you for the feedback, its appreciated.

The 7805 seems to be doing the job, without getting hot at all. The only thing i am using it for is for reference, so “no” current is being drawn.

Decoupling caps would be good

I have placed capacitors all the places i could imagine (motors and on all power inputs to the individual IC) it could be needed, have a look at the new schematic… what do you think, do i need any more, perhaps on the power source of the Arduinos (9V battery). Would you put a cap on the pot as well?

Not really needed on the pots, 0.1uF will help smooth out any high frequency noise that may get in, or with mechanical roughness as the pot moves over the resistive material.