This time I need to find a circuit that will generate a pwm output signal that is able to drive a servo motor. The output signal needs to ve controlled from a 0-5v input. What I want is that that the servo will adjust its position depending on the input voltage to the circuit.
I want to control a variable geometry turbo and a servo has it's own positioning control so I just need to tell it where it needs to be. I'm using a pressure sensor that goes from 0 to 30 psi and the voltage output is from 0 to 5v.
Anyone has a good idea or a circuit schematic with parts list to accomplish this? Most 555 circuits that I find out there involve moving a variable potentiometer to adjust the servos position.
If you removed VR1, R3, and D2, then connected R2 directly to where the wiper was (pin 7 on the 555) - leaving everything else the same; then in theory the voltage change should effect the position of the servo (because all that VR1 is for is a voltage divider between the positive and negative rails - R3 and D2 - and R2 - are, I believe, just protection components).
At least - I think such a thing should work; hook a scope and/or servo to the output of the 555 (pin 3 after R4), and try it out - if the 555 dies, you haven't lost much...
That's true; I am not sure what kind of "servo" he is working with - I thought it was either some kind of custom thing he put together on his turbo, or maybe it used such a servo...? I guess if he needed something else, then that circuit probably wouldn't work, so we need more info on what he is working with (maybe a spec/data sheet would help here!). It might be a good starting point, at least...
Actually the servos that I'm planing to use has a neutral position "mid travel" of 1.5ms so basically I need the same pwm used to control hobby servos. I don't know much about electronics, just basics and how to solder properly. Bellow are the specifications of the servo that I plan to use for now. Thanks for the help so far.