Hi AAC folks
New to the forum tonight. Try to develop a circuit which produces a drive for a relay, using a 555. The relay drives a motor. The motor needs to rotate 1/2 turn, stop for 2 seconds and turn 1/2 turn to the rest position, then wait until triggered to start again. I have a pushbutton to start things off. Thinking of using micro switches to detect final stop/start position (like a garage door opener, which has two limits switches, upper and lower). So, the sequence of event is as follows. Push the button. In case that pulse is too short and the motor doesn't move far enough to release the micro switch (open to closed), I was thinking of a 555 one-shot to bypass the micro switch for 1/2 second, but it needs to drive a relay because the motor draws 1 amp. So, relay contacts in parallel with micro switch's NO contacts in case they don't close as fast as the push button signal lasts. OK, motor's turning and gets to 180 degrees. Need to stop for 2 seconds. Upper limit microswitch interrupts current. If I put this micro while in series with the motor on the low side, I can use the contacts to generate a 5->0V signal, triggering another 555 monostable to generate a 2 second high, and when it drops to 0V, pull another relay to bypass the upper limit microswitch to get things going again. Finally, at 360 degrees, the lower limit micro switch kicks in and cuts the current. Now, to start over, push the button, start the motor, trigger the 555 to ensure a clean start.
All you smarter than me folks out there... does this sound right or is there a better way? All I need is the motor to turn in response to a push button, turn once, but stop half way round and wait for 2 seconds.
I was thinking of triggering a 1 of 16 decoder chip clocking at 8 Hz, and only connecting the first 2 and last 2 outputs, so the 0's in the middle section would simply be unable to drive the relay (just time passing by). So my output would be 0,0,1,1,1,1,1,1,1,1,1,1,1,1,0,0, so the motor turns, stops, turns, and I can always adjust the number of outputs or clock to match motor speed to mechanical load. I still need the micro to ensure end of cycle is mechanically correct, and push button to start it all.
I would appreciate any thoughts on this. I need to make this thing tomorrow, or even tonight !!! Thanks.
Ron
New to the forum tonight. Try to develop a circuit which produces a drive for a relay, using a 555. The relay drives a motor. The motor needs to rotate 1/2 turn, stop for 2 seconds and turn 1/2 turn to the rest position, then wait until triggered to start again. I have a pushbutton to start things off. Thinking of using micro switches to detect final stop/start position (like a garage door opener, which has two limits switches, upper and lower). So, the sequence of event is as follows. Push the button. In case that pulse is too short and the motor doesn't move far enough to release the micro switch (open to closed), I was thinking of a 555 one-shot to bypass the micro switch for 1/2 second, but it needs to drive a relay because the motor draws 1 amp. So, relay contacts in parallel with micro switch's NO contacts in case they don't close as fast as the push button signal lasts. OK, motor's turning and gets to 180 degrees. Need to stop for 2 seconds. Upper limit microswitch interrupts current. If I put this micro while in series with the motor on the low side, I can use the contacts to generate a 5->0V signal, triggering another 555 monostable to generate a 2 second high, and when it drops to 0V, pull another relay to bypass the upper limit microswitch to get things going again. Finally, at 360 degrees, the lower limit micro switch kicks in and cuts the current. Now, to start over, push the button, start the motor, trigger the 555 to ensure a clean start.
All you smarter than me folks out there... does this sound right or is there a better way? All I need is the motor to turn in response to a push button, turn once, but stop half way round and wait for 2 seconds.
I was thinking of triggering a 1 of 16 decoder chip clocking at 8 Hz, and only connecting the first 2 and last 2 outputs, so the 0's in the middle section would simply be unable to drive the relay (just time passing by). So my output would be 0,0,1,1,1,1,1,1,1,1,1,1,1,1,0,0, so the motor turns, stops, turns, and I can always adjust the number of outputs or clock to match motor speed to mechanical load. I still need the micro to ensure end of cycle is mechanically correct, and push button to start it all.
I would appreciate any thoughts on this. I need to make this thing tomorrow, or even tonight !!! Thanks.
Ron