servo motor control

yaj05

i got a problem on how to control my servo motor.. Using the BS2 usb type module, i have to put the switch to number 2 if i want to use the servo functions right? but what should i do if i will take the BS2 IC from the module and put it on my self designed board? the servo is not working anymore even i have the correct codes. but if i connect again the IC in the module, it works now.. can anyone tell me the schematic of the module's switches 1 & 2? any reliable answer will help. thanks!

Mike Green

I don't understand what you're talking about. Perhaps a proposed schematic and code would help. An R/C servo motor doesn't need a switch. It needs a source of power (4.5V to 7.2V usually) and a connection to one microcontroller I/O pin. Look at the "Robotics with the BoeBot" tutorial for a detailed discussion of how servo motors work and how to control them with a Stamp. The USB Board of Education provides regulated power, a serial USB port for programming and convenient connection to the Stamp's I/O pins. You don't have to use the USB Board of Education.

erco

I think the OP is talking about the BoE's 3-position switch, which has OFF, 1 (stamp only, no servo power) and 2 (stamp and servo power).

You can certainly copy that feature on your own board. You could use one 3-position switch like the BoE, or two separate switches.

The switch is arranged to deliver +5V power to the Stamp through the big rectangular heat-sinked voltage regulator. Power to the servo headers is switched separately. You can change a BoE jumper to select either regulated +5V power to the headers, or direct +9V in. BTW, 9V is really too high for a servo, but the little rectangular 9V batteries poop out (they have no current capacity) before they can do any servo damage. If you're making your own custom PCB, you may be using a bigger battery which could do servo damage, so keep that ~6V max (7.2V is pushing it).