Custom Servo

I am currently trying to create a servo motor its special because the main shaft only has 3 full rotations and geared again to a pot that would only rotate 300 degrees, but have come to the hard part of its controller or drive. I have googled everywhere and have come up with just a couple schematics. Does anyone know a good tutorial or reference to create a servo controller? (not to control the servo but the pcb in a servo). Also any thoughts on using just a cheap encoder for position control?

Why not cannibalise an existing servo's controller?

I already did and I want to be able to make at least 8 of these without buying the servos.

I'm pretty sure you could buy servos for less than you could build the controllers. YMMV

I would say that hobbyking almost certainly has a cheaper servo than the cheapest possible arduino board. Plus you will get the pot to sense position etc all included. You just need to make sure that the hbridge in the servo is up to powering your motor,

Below is what is in typical servo chip. Bottom is an inexpensive servo that could be used for its control chip.

http://www.seattlerobotics.org/encoder/200009/S3003C.html

http://www.hobbyking.com/hobbyking/store/__9549__Turnigy_TG9e_9g_1_5kg_0_10sec_Eco_Micro_Servo.html

I have used a few of the TG9 servos, be aware that the H bridge is designed for controlling the small motor in the servo. It will drive a bigger one, but will "PUFF" if you change it too much ,

if you want to learn about the servo control then there is a good sketch for reading the ppm in and you can learn about how to make an h bridge,

be aware that the H bridge is designed for controlling the small motor in the servo. It will drive a bigger one, but will "PUFF" if you change it too much

The small h-bridge in the small servo can be used to drive a larger h-bridge like below.

http://www.youtube.com/watch?v=Rpqsvw2iTIo

awesome, I could have used that on the rudder in an RC boat I made, I ended up using a massive hitec servo with something like 50kg of torque, But that I would have felt more succesful with a hacked one like that,

Google winch servo to find the type of servo you are trying to make and they are not that much more expensive that the ones you will be hacking.

Mark

Wouldnt a servo modded for continous rotation do the same as a winch?

On A Side Note, I sucessfulyy Controlled A 2 Tonne Winch With A Arduino And Motor Esc, Plus Some Switches For Safety Cutoffs.

Nice To See Someone From Poole, Im From Bear Cross

You don't have the control over position with a continous servo a winch servo has the gearing mod'ed to allow more than 1/2 a turn.

Mark

spruce_m00se: On A Side Note, I sucessfulyy Controlled A 2 Tonne Winch With A Arduino And Motor Esc, Plus Some Switches For Safety Cutoffs.

I was planning on using the innards of a $2 servo and a large h-bridge to make the below winch into a giant servo. Perhaps an ESC for a brushed motor might do.

Exactly, a brushed esc ,, make suremits from a car and hasmreverse. My aplicatiin didnt need a brake, but you may need to invent one