Need help with a geared motor

[Nigel Goodwin]

Even a circuit that complex takes only 7.45KB in GIF or PNG

Nice job cleaning it up!, otherwise it would be larger as a PNG than as a JPG (but I'm sure you already know that!).

 

[eblc1388]

Nice job cleaning it up!, otherwise it would be larger as a PNG than as a JPG (but I'm sure you already know that!).

I just use the graphic software to reduce the jpg color depth to 2(i.e. black and white) and bingo its done. I then saved it to PNG format.

I thought Audioguru would like to keep a copy of it because its his "first".

 

[audioguru]

Hi L. Chung,
I didn't know that the "hiss" all over my JPG was just coloured noise.

 

[eblc1388]

Hi L. Chung,
I didn't know that the "hiss" all over my JPG was just coloured noise.

Where can I buy a bi-color LED which give off different color light in opposite direction? :lol:

 

[audioguru]

Hi L. Chung,
Red and green LEDs in one package have been available from LED manufacturers for many years.
Two-wire ones have the LEDs back-to-back so the two colours are determined by the polarity. If you feed it AC then both LEDs light-up producing yellow!
Three wire ones are common-cathode I think, with the two LEDs separate so they can make red, orange I think, yellow, yellowish-green I think and green.

I have an LED that alternates red and blue with a built-in oscillator.
Red, Green, Blue (RGB) LEDs are available with 3 LEDs in one package to make any colour you want.

 

[crunch53]

So anyway are the diodes necessary in that circuit? Right now I am running it without them. I do need something to keep the motor running for 2 to 3 seconds after the switch is pushed until the cam pushes the micro switch in for the rest of the revolution. I might be able to build the flat on the cam up a little bit but I would still need to do it for about a second. Any suggestions?

 

[Roff]

This should hold the motor on for a couple of seconds or so. You can change the amount of time by changing C1 and/or R2. The diode will protect the MOSFET from voltage spikes generated by the motor.

 

[eblc1388]

There is nothing wrong with Ron's circuit.
There is nothing wrong with Ron's circuit........

This is offered for discussion only, based on the idea by Zevon8. Resistor Rx is there to provide the minimum holding current to the SCR to prevent commutation of the motor turning off the SCR.

Ron's circuit uses the limit switch NO contact while this circuit uses the NC contact.

The subtle difference is that Ron's circuit will stop the motor when the flat on the CAM comes up to the limit switch while this circuit would stop the motor when the switch reaches the end of the flat.

 

[zevon8]

There is nothing wrong with Ron's circuit.
There is nothing wrong with Ron's circuit........

Nice work on the SCR design. Rx would likely be neccessary in most cases, good catch.

 

[Roff]

There is nothing wrong with Ron's circuit.
There is nothing wrong with Ron's circuit........

This is offered for discussion only, based on the idea by Zevon8. Resistor Rx is there to provide the minimum holding current to the SCR to prevent commutation of the motor turning off the SCR.

Ron's circuit uses the limit switch NO contact while this circuit uses the NC contact.

The subtle difference is that Ron's circuit will stop the motor when the flat on the CAM comes up to the limit switch while this circuit would stop the motor when the switch reaches the end of the flat.

Elegant solution, LC.