Here you go…
http://www.webcom.com/sknkwrks/bighbrig.jpg
http://www.webcom.com/sknkwrks/partside.jpg
http://www.webcom.com/sknkwrks/servo.jpg
From this site. I didn’t think the site would still be up, but it is.
Heads up, I don’t know that I would try that verbatim from a +12V pack… you will get cross conduction from top to bottom at the higher voltage. You still get some at the +7.2V on the sketch but the MOSFETs are still in their amplifier region (rather than the fully ON switch region) so it just winds up being power dissipation and a good amount of rock and roll on the power supply.
Is there a list of parts? 
Im not sure what kind of pot that is. 
Hey Joe, go to the site and read / print. There is much information there. The pots are normal 1/4" shaft linear taper 5k ohm. You can get them from lots of places.
I did go to the site. Some of the links weren’t working for me, it may have been a bad connection though since I am running wireless.
Well there is a parts list, just for the FET’s, and all of the links appear to be working for the monster servo part anyway. As far as pots go…
A google search for - 1/4" 10k linear taper potentiometer - resulted in 2500 hits. The third one down works…
oselectronics.com/ose_p74.htm
They can be had from any lcoal radio shack for $2 or $3 as well. they generally have 5K, 10K, 50K, etc.
Excellant web page! They have already done most of what I was trying to find out. Interesting H-bridge design too. As to getting another pot, I’d use the one that is included with the servo (correct value for the board already). In the shot below it is seen removed from the Hitec HS-422 servo. The Hitec HS-422 disassembles much easier than other inexpensive servos which have the motor and pot directly soldered to the board. Due to the slower movement of highly geared motors, getting joint position info from the pot may become important when programming multiple moves.
But can that pot be positioned like this:
The shaft of that pot dosent look like it could be connected in this way, unless you had another idea im not aware of.
If you are acually going to use the pot as a load bearing bearing, then you will need something bigger than the servo pot. You might try Radio Shack.
yes, I know, I just didnt know how you were going to implement the Servo’s original pot, I understand now though, sorry for the confusion 
Hey zoomkat, which web page are you refering too ?
One other thing to consider is using this setup as a large motor speed controller. Setup somewhat like a continous rotation servo, the speed and direction omotor rotation could be controlled. I’ll look at the speed control range of the 12v motor I have. In the BGMicro link I posted, on the front page they have a 60A P MOSFET for $1.49, and some 70-75A N MOSFETs for $1.79. They also have a 28A N for $1.49 and a 23A P for $1.99. In the regular catalog they also have 30A 12v SPDT relays for $1.99. Looks like it might be possible to make fairly high current H-bridges for less than $10.00 each. More tinkering and testing to do.
Thats really good, since I kind of had the idea to recreate that SHB-01. Would it be possible or would you have to program it. I think ifs its possible the only requirements we would need is bigger mosfets to take the amps.
No programming involved in a basic h-bridge, just supply it with the desired input. One would control it by sending servo control signals between the range of maybe 1460 to 1540, with 1500 being the center point where the motor is stopped.
ok, so one would need a parts list for the SHB-01 and replace the mosfets and other neccessary components (resistors ect) with more powerful or more desireable kinds. Than a simple .5w pot from radioshack (or Canadian Source CC*).
sounds interesting, I would do it if it wasnt science fair time, have to complete my project.
One would only need the parts list/schematic for the SHB-01 if one wanted to duplicate that h-bridge. Otherwise just get a schematic and the parts for the h-bridge that one wants to make. I don’t know if any construction details for the SHB-01 are publically available, so duplicting one exactly may not be an option. I’m interested in the h-bridge made by the lawnmower guys as they apparently actually made one and reported that it works using the servo board outputs to the servo motor for control pulses. I guess the task now is to make one and verify that it is good solution for controlling large 12v motors. Probably time for a parts order to BGmicro.
The lawn mower project used an HS-805 but they retained the motor and geartrain, they just added the FET driver to eliminate the losses in the bipolar transistor stage. I posted it here with the asumption that a larger motor could be used instead of the servos motor. I don’t really know why an HS-422 motor amp couldn’t be used to drive the FET’s. 8)
In my test I am driving my MOSFET switch using the output of the h-bridge in the HS-422, which basically indicates I can drive a much larger h-bridge for larger than servo motors, such as auto windshield wiper and electric window motors. The below picture is the lawn mower guys doing something similar with a large gear head motor. Bottom is a winch that might make a giant servo if an appropriate bracket is carefully welded to the spool. Maybe somebody could be inspired to make a 5 or 6 foot tall Brat. 
http://www.webcom.com/sknkwrks/dwltserv.jpg
harborfreight.com/cpi/ctaf/d … mber=92860
