Servos can draw a good bit of power when they start or are under load. What you posted indicates you just assumed the power requirements for the servos and never actually measured their current draw, especially the starting current.
The reason I haven't measured the current is twofold:
1) I don't have a multimeter capable of measuring more than 200mA. As the servos would likely draw much more than that, hooking them up to the meter would just blow the fuse.
2) Measuring the current draw of my servos wouldn't provide me with particularly useful information because I can't count on these same servos being used with the final circuit. I have to design the circuit with all sub-micro servos in mind. And the best way to do that which is within my budget is to find someone who's tested lots of different servos to see how much current they draw at peak usage.
Like this fellow for example:http://homepages.paradise.net.nz/bhabbott/Servo.html
The LEDs dim and the board/servos may have performance issues because you are not able to supply adequate current when the servos start. Your regulator/battery setup is inadequate for the job.
A standard 9v battery is not made for powering servo motors and you are just waisting your $$$ trying to do so. Kind of like trying to start your car using flashlight batterys
If that's true then why does the circuit run fine off a 9v, but poorly off of six AAAs? Aren't AAAs capable of supplying way more current than a 9v battery?
I have yet to find a good source of information on the web on how much different types of batteries can source, but it looks like a AA might be good for 700mA to 2A, and a 9V might be good up to 1A. AAAs would obviously source less than a AA, but as far as I know, a 9v simply contains a bunch of AAAAs, and as such should supply less current than a AAA can.
I'm not saying you're wrong about the current it can supply. I mean it sure seems like it's getting drained fast. And I know the maH rating is far lower than the AAAs. But SOMETHING was going on in my circuit to cause the 9v to light everyhting properly and t make the servos run at higher speed. And something is causing the AAAs to fail at supplying enough current to keep the LEDs lit uniformly. Simply stating that the batteries csan't supply the current needed doesn't explain these things.
Noise is not your issue, being under powered is
I know that. I didn't title the thread "How do I provide more current to servos when they need it?" for nothing. :-)
(see if you recognize your battery holder in the below link)
That fellow is trying to power 12 servos. I'm trying to power two.
I've provide potential success paths, but they just seem to be questioned or ignored. It is like Rippley's "Believe it or Not" musem at the beach, you can believe it..., or not.
I'm questioning your suggestions because you're not providing enough information.
Telling me to stick a capacitor and a diode on there is of no help if I don't know how to wire them up, or how they're supposed to fix my problem. Do you expect me to order a couple diodes with a low voltage drop from Mouser, pay $5 for shipping, wait three days for them to arrive, stick them in my circuit, and hope they work, with no understanding of why they're supposed to work, and no guarantee that they will work?
Here's the first suggestion you offered:
You told me I should wire my circut up like this, but you gave no explanation for what any of these diodes were supposed to do.
Then pwillard had this to say:
You REALLY REALLY want to ISOLATE the Servo Supply from the rest of the circuit. Your current solution will still let the servo loading and spiking to impact the stability of the pseudo 5V source you now have relying on voltage drop on diodes.
Which apparently was a comment on the circuit you posted.
So you're telling me to do one thing, and he's telling me that's bad. And nobody else has any comment on the matter. And I don't have a clue. And you're not offering any explanation for how your circuit is supposed to work.
And you're surprised that I question this?
The next suggestion you offered was:
Power the rest of the circuit thru a low voltage drop (.1v) diode, and use a high value capacitor down stream of the diode to minimize the voltage disturbance to the circuit.
The problem with that is:
1) As far as I can tell, no such diode exists. Even those Schottky diodes you've suggested only seem to go down to 0.3v.
2) There's still that thing that pwillard said about it being bad to power your circuit through diodes which concerns me.
3) You never did answer what you meant by a "high value capacitor". Is 47uF high value? Is 100uF? 220uf? 470uF?
4) Your explanation for how to wire the circuit is unclear. "Stick a capacitor downstream" is meaningless to me.
Do you want me to do this?
Regulator output -> Servo ->
- Diode[-] ->
- Capacitor[-]- -> Arduino
I don't know how that would work. If I understand capacitors correctly, the capacitor would pull down on the Ardunio's voltage line as the capacitor charges, assuming there's some route to ground. Then once the capacitor is fully charged, current would simply stop flowing. The Arduino would never power up.
Or do you want me to do this?
Regulator output -> Servo ->
- Diode[-] ->
- Capacitor -> Arduino Vcc
Capacitor[-] -> Ground
That would function I guess, but how is it a solution to my problem? how is that different from any other bypass capacitor, of which I have tried several? What does the diode do that makes it different?
Does the diode allow the capacitor to charge, but prevent it from discharging back into the servos perhaps?
5) You said doing this will minimize the voltage disturbance to the circuit. But you just said the problem with my circuit was not noise, but being under powered because the batteries can't supply enough current.
So how is a solution designed to minimize voltage disturbance, which I read as "minimize noise", going to solve my problem of not having enough current?