i been with with making my own home made servos best way is to take futaba 3003 ,AND TAKE IT APART and remove the motor and feedback pot 5 k pot its the cheapest,and remove the h-bridge and add you own depending on motor and stall curent made well over 100 and some at 50 amps to drive wheelchair motors ebat has them for about, $3.50 and then add a gear box if needed the pot goes on the output shaft going to item you want to control i have a circuit of the FUTABA S3003 can buy a servo board and add your own feedback pot,board is $20 plus shipping caled open servo project,but about the same as a S3003 AT LESS THEN $4 icluding shipping i use that design in all my robot toy projects like RAD 2.0,THE ROVER,and many more,all the cheap robot toys only use a motor and no feedback,there are many other feedback types,opto encoder high cost,magnetic kinda high cost, like use in the NEATO motors,then EMF feedback off the motor (not really accurate) ,but i think you are looking at a low cost design used in servos i have lots and lots of info on this

@robotmaker - that is what I am looking for, for sure. Could you maybe do some pics and step by step? I can do the work if someone points me in the right direction, but I am not that tech savvy. THhanks.

ok can do that pretty easy.i have also design h- bridges also will need info on motors like model # or the load you want to lift ,carry or move

rgordon that is a good link seen it many times ,it same idea i use in many of my projects very simple and easy and cheap high power servo's here is the schematic of the FUTABA S3003 servo ITS LIKE MY BIBLE futaba s3003 schematic

the h-bridge it rated at 1 amp and can put 2 in parallel to get 2 amps now on interfacing to a h-bridge some need simple digital circuit ,some with ccw and cw like in schematic dont need anything

i made my own circuit board for digital circuit and made boards for my h-bridge design 60 amps will post them HBRIDGE.zip files in bmp and sch,i mostly send my circuit out to be made making boards at home is lot of trouble and there is a few days to make them if only one board with many parts or few,i make with protoboard called vector board with holes .100 apart using buss wire,done it with one chip and 20 chips doesnt matter

in my design i do have servo to pwm circuit not really good,no feedback h-bridge design is in 2 circuits h-bridge and pwm circuit

robotmaker I would like for you to take a look at my idea for a servo mimic that I came up with. I t is different than the link I posted. It is listed later on in the thread on second page. I put up an idea for a servo mimic with several drawings. Wanted you thoughts on my idea.

Also thanks for the H-Bridge schematic. I would like to try that also.

RGORDON relays are the worst idea for controlling that old school design before h-bridge ,relay have a chatter problem,contacts wear out,plus draw alot of current now limit switches can be used ,but not neededalmost because using a feedback pot on turntable from the feedback position you can set the limits in the micro code

robotmaker

Thanks for your input. I don't have any experience yet with micro-controllers and programming and this was just way to save money instead of buying expensive high torque servos. I still may try it just to see if it works.

I appreciate you looking at it.

taking FUTABA S3003 servo apart and adding h-bridge wont need any programming code i am talking about is scripts in EZB board ,and me or anyone else can help with that