how to design the window lifter motor continuously running forward and reverse with control of magnetic reed switch

arunpandiant24 said:

I don't use microcontroller .this for only demo purpose. I need 1-minute delay with simple circuits of components . I hope you can help me out.

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Les Jones said:

My original idea was to use a NE555 or CD4060 configured to work as a 1 second monostable that was triggered by either limit switch closing. (Via a diode OR gate.) This would remove drive to the relays for 1 second after each limit switch closed.
After seeing rjenkinsgb's post #22 I realised that this was a much better solution.
This is my implementation of his suggestion.
View attachment 124740

If you are not familiar with "Eagle PCB" IC1P is just the way it shows the power pin connections (8 & 16) of the CD4060.
D3 is to isolate the power to the CD4060 from dips on the 12 volt supply caused by the starting current of the motor.

Edit. I have noticed in the first sentence of this post I said "1 second monostable" . I should have said 1 minute monostable. When I was doing a mental calculation for a suitable oscillator frequency I continued thinking in seconds (Rather than minutes.) so I selected the wrong output from the CD4060. I also made another mistake in thinking the first stage was called Q0. It is called Q1. The result of these two errors means that the output Q14 should be used instead of Q7. (The wire shown on the schematic going to pin 6 of the CD4060 should go to pin 3.)

Les.

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Les Jones said:

Why do you want to use a NE555 instead of a CD4060 ? The CD4060 will give much better timing stability than the NE555 for delays of one minute. With the NE555 you will probably use an electrolytic capacitor for timing. (Probably around 10 uF) The tolerance of electrolytic capacitors is typically + 50% , -20%. Their leakage current is much higher than a metal film capacitor and will vary with time and temperature. This will be significant when using a high value timing resistor (About 6 Meg ohms) which will be required for the long delay time of 1 minute. You could use metal film capacitors but these will be much more expensive and much larger.
With the lack of background information this is starting to sound like a school project. Is this the case ?

Les.

Click to expand...

Les Jones said:

My original idea was to use a NE555 or CD4060 configured to work as a 1 second monostable that was triggered by either limit switch closing. (Via a diode OR gate.) This would remove drive to the relays for 1 second after each limit switch closed.
After seeing rjenkinsgb's post #22 I realised that this was a much better solution.
This is my implementation of his suggestion.
View attachment 124740

If you are not familiar with "Eagle PCB" IC1P is just the way it shows the power pin connections (8 & 16) of the CD4060.
D3 is to isolate the power to the CD4060 from dips on the 12 volt supply caused by the starting current of the motor.

Edit. I have noticed in the first sentence of this post I said "1 second monostable" . I should have said 1 minute monostable. When I was doing a mental calculation for a suitable oscillator frequency I continued thinking in seconds (Rather than minutes.) so I selected the wrong output from the CD4060. I also made another mistake in thinking the first stage was called Q0. It is called Q1. The result of these two errors means that the output Q14 should be used instead of Q7. (The wire shown on the schematic going to pin 6 of the CD4060 should go to pin 3.)

Les.

Click to expand...

Les Jones said:

I think the problem is around the mosfet Q3. I don't think it is inverting the output of Q14 on the 4060. This is how I would trace the problem. Position the motor so that neither limit switch is actuated. Disconnect the motor. Power on the circuit. wait until Q14 goes high. Measure the voltage with respect to the supply negative at the gate of Q3 and at the drain of Q3 The gate should be at least +6 volts. (It will probably be close to + 12 volts.) The drain should be close to zero volts. Report the results. It might be useful to add an LED and resistor to each relay coil to show when it is actuated. I suspect that when the window should be going up it is not doing so because both relays are actuated.

Les.

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Les Jones said:

I don't understand what you have measured when you say "I measured the supply negative at Q3 gate and drain is +12v. "
With neither limit switch actuated and the motor disconnected do the following. With your meter set to the 20 volt DC range connect the black lead from your meter to the supply negative. Connect the red lead from your meter to Q14 on the 4060. Wait for it to go to logic high. (About +12 volts) You now have about 1 minute to do these tests as they must be done whole Q14 is high. connect the red lead from the meter the the gate of Q3 and note the reading. Move the red lead to the drain of Q3 and note the reading. I don't know how you have constructed the circuit but on the assumption that it it is using one of these breadboard things there could be a bad connection so confirm the voltage on Q3 source pin is zero volts. also measure the voltages directly on both ends of R4. A picture of the way you have built the circuit may be helpful. If my guess is right that you mean that there is zero volts on Q3 gate then it is shorted to the supply negative or there is a break in the path between Q14 via R4 to the gate of Q3.

Les.

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Les Jones said:

I think Q3 is faulty. Probably with a gate to drain short.

Les.

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