Saturday, January 16, 2010

How can i control 4 r/c servos from pc?

i'm mechatronic student on technical highschool and i need this for my bomb robot project.How can i control 4 r/c servos from pc?
Hobby r/c servos use pulse width to control the position. The basic pulse is 1 ms. making this pulse larger or smaller moves the servo.How can i control 4 r/c servos from pc?
not a chance... go ask a U.S. marine. he'll help you determine the speed of a 308.....
RC servos are a staple of the hobby robotics industry. We use them all the time.


The quick answer is a servo control PCB. These are circuit boards made specifically to control servos and be controlled by a PC connection (USB or serial). I carry several in my store. The smallest ones usually control up to 16 servos.


I carry ones by Yost Engineering, Robotics Connection, and Hitec Robotics. There are others made by companies like Parallax, Phidgets or Blue Point Engineering.
I'll assume you want to keep this simple and continue to use your existing transmitters rather than starting from scratch by building your own transmitters -- that'd be a MUCH bigger project. The boards mentioned below would imply that you're willing to be ';tethered';, and your use of R/C in the question implies you wish to remain wireless.





Your typical PWM R/C servo transmitter system uses voltage changes (usually caused through the use of potentiometers/joysticks) to modulate the content of the RF signal that your transmitter to your receiver. You can accomplish the same thing by generating the voltage using D to A (Digital to Analog) circuits. You'll need to meter the circuit to determine typical voltages generated by the pots and generate that same range of voltages externally and feed them into the circuit in place of the voltages created by the pots.





Many companies sell A to D and D to A boards for PCs. Some operate over USB, and others plug directly into the computer's backplane.





You then use those voltages to replace the potentiometers on your transmitters.





You then write simple software to control the output of these D to A boards which in turn control your R/C transmitters.





Some companies you might want to include in your investigation include National Instruments (www.ni.com), and IOTech (www.iotech.com). Measurement Computing (www.measurementcomputing.com) has some reasonably inexpensive USB models that are well worth a look -- see 4 channel unit at the following link:


http://www.measurementcomputing.com/cbic鈥?/a>





Just remember, you need something with qty 4 D to A channels if possible to avoid having to buy multiple units.

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