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Topic: Arduino-Uno(R3) Power Loss When +/- Connected (Read 1 time) previous topic - next topic

jmwst1

Hello!

I am working on a beginner project, and am having an issue that causes complete power loss on the Arduino when both the 5V and GND connections are in place from the Arduino to the breadboard.

If i just connect one of either the 5V or GND, then I can get the servo and motors working, but still have issues.  Once I connect them both, the Arduino just shuts down.

I have rewired everything many times as well as changing out the breadboard and servo.  When I removed everything else in the cabling and just left the 5V and the GND in place the Arduino stayed powered.  This is my first real project; am I just missing something simple here?

The wiring schematic for the project is here: https://lh4.googleusercontent.com/-EgQK-VJRL54/TgHt3Sw1AxI/AAAAAAAAAPQ/Padivqv49YQ/s640/circuit.jpg

(Full project documentation: http://communityofrobots.com/tutorial/kawal/how-make-your-first-robot-using-arduino)

I appreciate any feedback or input!

weedpharma

It sounds like you are drawing too much power in your breadboard. Run the breadboard from its own supply, not via the Arduino supply.

Don't forget to join the ground from the separate supply to the Arduino ground.

Weedpharma

jmwst1

Thanks for the response.  I have a separate 6V supply into the breadboard, but not into a power rail. It goes into row 19, which connects to the motor driver and the servo.  Does that make sense or should it come into a the power rail and then be cabled over?

runaway_pancake

"Who is like unto the beast? who is able to make war with him?"
When all else fails, check your wiring!

sterretje

It goes into row 19, which connects to the motor driver and the servo.  Does that make sense or should it come into a the power rail and then be cabled over?
It makes sense. The schematic seems OK; the 'power rail' is just a horizontal rail and you use a vertical rail; no issues with that.

If you understand an example, use it.
If you don't understand an example, don't use it.

Electronics engineer by trade, software engineer by profession. Trying to get back into electronics after 15 years absence.

septillion

I can't spot the error right away... But I do miss the diodes. Datasheet states:
Quote
On the L293, external high-speed output clamp diodes should be used for inductive transient suppression.
Also I would PWM the enable line for speed and use logic levels for the A lines. Saves PWM pins and the motor can freerun in between the pulses. If you PWM the A line it will brake when the PWM line is low.
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