18V DC motor on/off switch using distance sensor

Thread Starter

Logo

Joined Feb 18, 2011
6
Hi, i am a student in Norway and am trying to make a small circuit to run an 18v motor that is drawing about 5Amps basiclly the motor needs to turn on when it gets something is within about 5-10cm of the sensor (just before and just after this the distance will be about 80cm)(it could also be a IR light beam or laser light beam that is broken when something moves in front) and stay on for 1-2 seconds after the distance goes over 5-10 cm or the light beam is unbroken. It would also need an override button that when the button is pushed the motor would stop for about 5 seconds before being able to start again.... that is all i need and i still have not managed to build it in the last 3 days, i have access to a very good selection of resistors, MOSFETs, caps and trasistors i also have a "HC-SR04 Ping distance sensor" but as i dont want to use an Arduino i am not sure that it is any good to me, i did manage to connect it up so that i got a voltage variation of 0.4V (from 1 volt to 0.6 volts) when moving my hand from 5cm to 20cm when it was connected to a 5v supply..... anyway if there is anyone that can help me with a circuit diagram for this and what parts i should use i would be more than happy to send a $20 paypal payment :) thanks for reading :)
 

mcasale

Joined Jul 18, 2011
210
I don't think folks are allowed to "get paid" for their advice.

Can you share the specs on the motor? Is it DC, AC, or a stepper? The motor driver depends greatly on the type of motor.

From your description, it sounds like the motor is mounted to some stationary platform, and your circuit is trying to sense "something" that gets in its vicinity. Correct?

Why not use an Arduino?
 

Thread Starter

Logo

Joined Feb 18, 2011
6
Hi thanks for the reply, yes it is a DC motor out of an old handheld battery vacuum cleaner, there are no electronics on the motor its self, just a couple of caps, and yes the motor is stationary, and yes the motor needs to start to create a vacuum when the sensor detects an object that is close to it.

I did not want to use an Arduino because i wanted all the parts to be replaceable anywhere in the world :)
 

mcasale

Joined Jul 18, 2011
210
Driving a DC motor is pretty straightforward. I'm thinking the tough part is figuring out how to use the sensor. It seems to be essentially a digital device. I found a posting where it is interfaced to an Arduino, and he provides source code.

A power MOSFET would be a good switch to turn the motor on.

Doing the logic to figure out distances is going to be tough in the analog world.
 

Thread Starter

Logo

Joined Feb 18, 2011
6
Ok and if I was just to drop the Arduino sensor and just use a IR sender and receiver would that be easier do you think?
 
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