rat_race_123
Posts: 5
Joined: Thu Feb 16, 2017 6:52 am

L293D only outputting 1V to DC motor

Thu Nov 30, 2017 5:43 am

I am running through the sunfounder lesson on driving a DC motor (link below) but the DC motor does not move. I have checked voltages on everything and the one thing that is odd is the output voltage from the L293D output pins (1Y and 2Y) is only 1V. The voltage output from the power module is 5V (double checked) and the pins are switching on and off as they should, however they are only switching between 0 and 1V.

Vcc2 is getting 5V and that is what the driver power. Could the L293D be bad? I have never used it before. I have checked wiring a million times and it is good, and the code is good as I copied sunfounder code. Any help is appreciated.

Also the motor is fine because I can plug it into 5V off the power module directly and it runs.

Sunfounder Link:
https://www.sunfounder.com/learn/Super_ ... ry-pi.html

L293D link:
http://www.ti.com/lit/ds/symlink/l293.pdf

QMESAR
Posts: 55
Joined: Wed Sep 06, 2017 10:41 am

Re: L293D only outputting 1V to DC motor

Thu Nov 30, 2017 6:24 am

Hi
the voltage output from the power module is 5V (double checked) and the pins are switching on and off as they should, however they are only switching between 0 and 1V.
I am not sure too which pins you refer however is it the IN1 and IN2 and the Enable pins then you have electrical error as for switching your driver you need
IN1 -logic High at lest above 2.3V as per datasheet
IN2 to low 0V below 1.5V as per data sheet
Enable should be Logic High above 2,3V
for one direction and for the other direction the Low /High sequence change vise versa
with your specified voltage levels for the logic control the driver will never switch ON
another topic to consider is that this configuration only drive the motor at full speed there is no speed control as when the driver switch on it apply full V-supply to the motor if you will need speed control you need to implement a PWM control
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pcmanbob
Posts: 9464
Joined: Fri May 31, 2013 9:28 pm
Location: Mansfield UK

Re: L293D only outputting 1V to DC motor

Thu Nov 30, 2017 10:41 am

You should be able to drive n L293D from the pi gpio with out any problem.

So you either have a mistake in your wiring, a mistake in your code or your chip is bad.

So to test chip without the pi just connect the motor in the diagram above to output 1 & 2, connect Enable1,2 to 5v, connect input 1 to 5v and input 2 to ground with power on motor should spin, if you reverse the connections to input 1 and 2 the motor should reverse also. for this test connect both vcc1 & 2 to 5v

Once you know the chip is ok then reconnect to pi gpio checking wiring as you go, if you still can get it to work then post your code and a good quality picture showing wiring to chip and gpio.
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