Thread: reversable motor for monitor?

Originally Posted by Ricky327

Infact you can probably even build this feature by using 555 timer...up to you.

I really dont know anything about doing this either way, so I dont know the advantages of doing it with that timer or the other way you mentioned.

MikeH say something...you disappeared

Originally Posted by Ricky327

MikeH say something...you disappeared

He's probably sleeping.

He's probably sleeping.

..yes he was..

I like Ricky's idea of a simple pullup/down transistor for the Opus. I don't care as much for the 555 timer since, with the current scheme, the PIC can be programmed for different delays which gives you much more flexibility. I know you could put a pot (...no, not the leafy stuff, a variable resistor) on the 555, but I always prefer to do as much as possible in software.

Here's a revised schematic with the "ricky-sistor". However, not knowing the specific input desing of the Opus, this may need some tweaking.

Originally Posted by MikeH

I know you could put a pot (...no, not the leafy stuff, a variable resistor)

Damn, I thought this was going to be something that In have some knowledge of.

Mike, what about the H bridge? You don't like it? I modified one of your designs last night and posted it, Ricky said it looked ok. Check a few post back.

I have never built an H-bridge, but yours is almost exactly the same as the one I posted. It looks OK to me, but again, I have no experience here. I just put a couple of pullup resistors on the top 2 (PNP) transistors to keep them off during startup when you PIC is not yet fully awake. No big deal. I would suggest you read up a bit on some of the robotic sites. They seem to suggest some noise suppression diodes and capacitors on the motor. But I think this is more for the guys who use radios to remotely control this stuff, rather than over voltage spike protection (a running motor puts of lots of RF noise and can jam your receiver).

Originally Posted by MikeH

I have never built an H-bridge, but yours is almost exactly the same as the one I posted. It looks OK to me, but again, I have no experience here. I just put a couple of pullup resistors on the top 2 (PNP) transistors to keep them off during startup when you PIC is not yet fully awake. No big deal. I would suggest you read up a bit on some of the robotic sites. They seem to suggest some noise suppression diodes and capacitors on the motor. But I think this is more for the guys who use radios to remotely control this stuff, rather than over voltage spike protection (a running motor puts of lots of RF noise and can jam your receiver).

Finally, something that I understand! I have some R/C experience so I know that a motor can cause radio noise. Its strange but the gas R/C have more of a problem with that.

I will try to learn about the H bridge, but it seems like most of the info I find about electronics is just over my head. Maybe Ricky can chime in on the H bridge.

I was thinking that I could use 2 LM7805's one for the PIC and one for the motor so that no matter how much the motor pulls it would not rob power from the PIC. Maybe it would also protect the PIC from my screw-ups. Does that sound like a good idea? It may be over kill but thats ok with me if it helps.

I was thinking that I could use 2 LM7805's one for the PIC and one for the motor so that no matter how much the motor pulls it would not rob power from the PIC. Maybe it would also protect the PIC from my screw-ups. Does that sound like a good idea? It may be over kill but thats ok with me if it helps.

Yes, it's probably a bit of overkill. But it would give you a great deal more isolation from the noise generated by the motor. Might not be a bad idea.

I order the PIC and the programmer today, damn now I have to learn how to write the code. Anyone know of a good tutorial for writing the code for motor control and switches?