Motors interfere with my Javelin
bulkhead
Posts: 405
I'm running two small DC motors through two H-bridge IC's hooked up to my Javelin. I'm also reading the buttons on a playstation controller. When I push and hold down a button, the motors are supposed to run in 1 direction continuously. However, in reality, they just jitter back and forth, sometimes they will run in the correct direction for a second before going back to jittering. Using the serial connection, I found that my Javelin wasn't reading the playstation controller's button as depressed, even though I was holding it down. The Javelin wasn't restarting, just reading the buttons incorrectly. Apparently, the motors interfere somehow with the Javelin, since if I replace the motors with LEDs, they light up and stay on as they should, when the button is depressed.
I've tried capacitors of all different sizes, and in different configurations on the motor, and none seem to help. I did have some success with an old "472" ceramic disc capacitor I took off from something else, but when I bought more "472"s from radio shack they didn't help at all. Sometimes, the interferance gets less when I put the motors under a load, and sometimes, putting them under a load increases the interferance. I also tried running two separate battery packs, it didn't help. I know these motors are capable of running fine, because earlier on, I hooked these motors with the same h-bridges up to my javlein, and it worked before. Now that everything is mounted and hooked up on my robot, it doesn't work fine. Any suggestions would be greatly appreciated, thanks.
I've tried capacitors of all different sizes, and in different configurations on the motor, and none seem to help. I did have some success with an old "472" ceramic disc capacitor I took off from something else, but when I bought more "472"s from radio shack they didn't help at all. Sometimes, the interferance gets less when I put the motors under a load, and sometimes, putting them under a load increases the interferance. I also tried running two separate battery packs, it didn't help. I know these motors are capable of running fine, because earlier on, I hooked these motors with the same h-bridges up to my javlein, and it worked before. Now that everything is mounted and hooked up on my robot, it doesn't work fine. Any suggestions would be greatly appreciated, thanks.
Comments
Alternatively, get this on an oscilloscope and see exactly what capacitor values will work best at cutting down the noise.
The button's might require a chip to provide debounce.· This is most easily done with a SPDT switch and 74HCxx Ic working as a flip-flop, but there are actual 'debouncing chips' available.· And, the IC [noparse][[/noparse]all your ICs need to have a 0.1mfd cap right at their point of supply].
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Post Edited (Kramer) : 4/3/2006 2:30:18 PM GMT