i want to mount 2 cheap motors on my boe bot..and i plan controlling them using high low commands.is there any chance that the electromagnetic noise of the motors affects the bs2 chip or the boe.
But first, you can't drive electric motors directly from a Stamp pin; it can't handle the current and the lack of any back EMF protection (e.g. a diode) could fry the pin in the long term.
There are a number of not particularly difficult methods to drive a motor from a Stamp pin; the best solution depends on if the motor depends on two things primarily: if you need to turn one direction only or both directions; your own skill level and comfort.
A transistor or two and a diode will do for one direction, or a self-contained transistor/diode array like the ULN2803A. For bi-directional control a home-brew H-bridge or a ready to go H-bridge like the L293D (which has motor diodes built-in) might be easiest; a caveat being that the Stamp is not well-equipped for running an H-bridge with a full range of speeds -- while doing anything else.
Of course, Parallax also offers some ready-to-go small motor controllers if you are not comfortable doing some of your own wiring.
That said, while there are sometimes a happy exceptions to the rule, noise suppression in the form decoupling capacitors on the motors, on the supplies to your other electronics are a must.
A .1uf or .01uf right across the motor terminals and across your power supply rails is a good place to start. If noise is still a problem, there are other avenues (3 capacitors on the motor terminals, with two tied between between a given terminal and the motor case; ferrite noise suppressors on the motor wiring; shielded wiring; etc).
motor
+---(M)---+
| |
| .1uf |
+---||----+-------> to motor driver
|
+-----------------> to motor driver
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ When the going gets weird, the weird turn pro. -- HST
Comments
But first, you can't drive electric motors directly from a Stamp pin; it can't handle the current and the lack of any back EMF protection (e.g. a diode) could fry the pin in the long term.
There are a number of not particularly difficult methods to drive a motor from a Stamp pin; the best solution depends on if the motor depends on two things primarily: if you need to turn one direction only or both directions; your own skill level and comfort.
A transistor or two and a diode will do for one direction, or a self-contained transistor/diode array like the ULN2803A. For bi-directional control a home-brew H-bridge or a ready to go H-bridge like the L293D (which has motor diodes built-in) might be easiest; a caveat being that the Stamp is not well-equipped for running an H-bridge with a full range of speeds -- while doing anything else.
Of course, Parallax also offers some ready-to-go small motor controllers if you are not comfortable doing some of your own wiring.
That said, while there are sometimes a happy exceptions to the rule, noise suppression in the form decoupling capacitors on the motors, on the supplies to your other electronics are a must.
A .1uf or .01uf right across the motor terminals and across your power supply rails is a good place to start. If noise is still a problem, there are other avenues (3 capacitors on the motor terminals, with two tied between between a given terminal and the motor case; ferrite noise suppressors on the motor wiring; shielded wiring; etc).
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
When the going gets weird, the weird turn pro. -- HST
1uffakind.com/robots/povBitMapBuilder.php
1uffakind.com/robots/resistorLadder.php
Post Edited (Zoot) : 9/27/2009 2:36:32 PM GMT