Can someone do this using only one motor, one battery, and one contact
I'm a tard. I just want a circuit that will drive a motor one
direction, then reverse direction when the contact is closed. NOT
using an alternating switch, just a simple switch. And, ONLY using ONE
battery. THANKS for the help!
John Craig <--- noob!
Is this some kind of homework assignment?
I hope the switch is not being hit by the action of the motor,because
as soon as it goes in reverse, it'll release the switch, causing it to go
forward, activating the switch, etc. causing it to just vibrate at the
point of switch crossover.
I'm not an expert, but I think the way you'll have to drive your motor is
with multiple voltage dividers and wasting a lot of energy.
if you have 4 resistors, 2 at 1x and 2 at 2x, for example.
One side of the motor has
Power -- 1x -- leg of motor -- 2x --- ground
and the other side
Power -- 2x -- other leg of motor -- 1x -- ground
Your motor would see about 1/3 of the power voltage.
Then put your switch across the 2x resistor to ground.
You can play with varations on this theme.
contact switch please!?!?
Look at the circuit on
Notice there are four "switches" in an H-bridge. By activating two of
them, on diagonals you can make a motor go one way. By opening them and
closing the other diagonal set, you can make the motor go the other way.
Now if you can accept that the four poles you see there can be arranged
into one switch body, you can have your goals met. A double pole double
throw switch (DPDT) will do the job. Pushed one way, the motor runs one
direction, pushed the other way the motor runs the other. You might
consider that an "alternating switch". (Not sure what that means.) So if
you want a Single Pole Single Throw switch (SPST), you can use it to
operate a relay with DPDT contacts on it, but you are adding one more
part, and a requirement for more current when the relay was active.
Please consider what Rufus has told you as well. The motor will only
reverse while the slide is in contact.
When I was a kid I had a toy cable car with this design on it. The car
would run on a taught string to one end, where a long arm would push
against the backstop, and throw a DPDT switch to the opposite position.
This would throw the car into reverse, running back to the other side.
It would remain in that state until contacting the other side with an
opposing arm which pushed the switch back. And so on.
Well, I figured it out. The purpose of the circuit was to create a
single motor BEAM with a single power source and a single touch sensor
(feeler). The BEAM constantly moves forward until the feeler hits an
object which causes the beam to reverse. Here is the circuit;
Thanks for the e-mail help and posts! I'll post pictures when it is
made. Hopefully tonight it'll be together. Here's a drawing for now;
Get some current limiting resistors, maybe a couple hundred ohms each,
in those base legs, of you'll over current the bases and burn out the
You may need to add clamping resistors to keep the off transistors
really off. Clamping resistors go from the base to the emiter of the
transistors (and come after the current limiting resistors). Usually,
the values are a few thousand ohms.
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.