1
\$\begingroup\$

If we start with the above circuit, it will drive motor one way and stop at one of the end stops. Can you suggest an idea to connect the circuit back with reversed polarity if I reverse the supply? The motor should stop and disconnect at the other endstopI have a circuit where two limit-switches to be wired with motors to do the following functionality. It is to be used in a remotely placed device so that the intervention of microcontroller on the working of the motor should be minimized.

The circuit shall perform the following operation

  • When the supply is positive the motor should rotate CW. After reaching the limit switch, the motor is to be disconnected from the supply. Afterwards, by using a trigger (maybe reversing the supply, for example) the motor should rotate counterclockwise to reach the other limit switch. After reaching the switch, the motor should be disconnected from the supply again. By keeping the motor in this position and if we again give another trigger, the motor should rotate clockwise again.

In short, the motor should rotate to and fro. The limit switches should disconnect the motor when the knob reaches the limit switches. A trigger should be there to make the disconnected circuit live again.

The circuit is to be used in mostly damped areas place. The motor is actually closing a water connection valve. It can be easily done by using some microcontrollers. But if the microcontroller or any of the small components like we may use as switches(diode, MOSFETs etc..) fails, it may result in utter loss of water.

The motor has a maximum rating of 3.6VDC. And the supply is a 3.3V Li-ion Battery.

The motor causes the knob to rotate which in turn pushes the limit switches.

\$\endgroup\$
11
  • 3
    \$\begingroup\$ Why can't the circuit contain any active devices? This sounds very much like a homework problem, so you should show us all of the work you have done so far. Do you know how to connect a single limit switch to stop a motor traveling in one direction? If this is not a homework problem, explain how you will trigger the motor, give specifications for the power supply, provide a link to the motor's datasheet, and tell us about the mechanical load on the motor. \$\endgroup\$ Aug 19, 2019 at 11:40
  • 2
    \$\begingroup\$ What is your question exacatly? If it is "Can you please design this for me?", please note this site is not a free design house. \$\endgroup\$
    – Huisman
    Aug 19, 2019 at 11:40
  • 1
    \$\begingroup\$ Huge hint: a rectifier is not an active device. \$\endgroup\$ Aug 19, 2019 at 11:43
  • \$\begingroup\$ @ElliotAlderson The circuit is to be used in mostly damped areas place. The motor is actually closing a water connection valve. It can be easily done by using some microcontrollers. But if the microcontroller or any of the small components like we may use as switches(diode, MOSFETs etc..) fails, it may result in utter loss of water. So we want to make it by minimizing the components as far as we can. I have explained the functionality it requires. I made some circuits but none of them can reconnect the circuit to rotate motor again after turning it OFF using limit switches. \$\endgroup\$ Aug 19, 2019 at 11:52
  • \$\begingroup\$ @Huisman I think the above comment clarifies the situation more. I am not wanting to design it for me, but I am rather stuck at that issue. Please have a look at the above comment, and thanks for your quick response.!! \$\endgroup\$ Aug 19, 2019 at 11:57

2 Answers 2

3
\$\begingroup\$

I believe this should work for what you want.

schematic

simulate this circuit – Schematic created using CircuitLab

\$\endgroup\$
7
  • \$\begingroup\$ Are you assuming that the limit switches are normally open, as you have drawn them? \$\endgroup\$ Aug 19, 2019 at 12:29
  • \$\begingroup\$ @ElliotAlderson yes..! \$\endgroup\$ Aug 19, 2019 at 12:30
  • 1
    \$\begingroup\$ @ElliotAlderson I am sure the OP gets the idea. \$\endgroup\$
    – HandyHowie
    Aug 19, 2019 at 12:31
  • \$\begingroup\$ @AmalnathSatyan Please add that information to the original question. The text of your question seems to imply that they are normally closed and "disconnect" the motor when it reaches the limit. \$\endgroup\$ Aug 19, 2019 at 12:32
  • \$\begingroup\$ @ElliotAlderson Updated \$\endgroup\$
    – HandyHowie
    Aug 19, 2019 at 12:33
-1
\$\begingroup\$

You need a circuit similar to this:

schematic

simulate this circuit – Schematic created using CircuitLab

Motor direction is selected by SW. The bumper switches BSW1 and BSW2 open as soon the respective end position is reached.

\$\endgroup\$
15
  • \$\begingroup\$ This will only provide 2.6V for the motor. Are you sure it will work? \$\endgroup\$ Aug 19, 2019 at 12:07
  • \$\begingroup\$ There are 0.5V solar motors. \$\endgroup\$
    – Janka
    Aug 19, 2019 at 12:08
  • \$\begingroup\$ But why would I use those diodes? \$\endgroup\$ Aug 19, 2019 at 12:10
  • \$\begingroup\$ The OP specified a motor with 3.6V max rating and a 3.3V battery. \$\endgroup\$ Aug 19, 2019 at 12:10
  • \$\begingroup\$ A DC motor with a 3.6V maximum rating will run at roughly half the maximum speed at 1.8V. So it will function just fine at 2.6V. \$\endgroup\$
    – Janka
    Aug 19, 2019 at 12:10

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.