Hello Everyone,
I'm working on an arduino project. My challenge is that the 5V output pin is giving me 6V when I connect the board to the circuit whose schematic I have attached below. Interestingly, when I take the arduino out of the circuit and plug it I get the expected volatge-5v
Any leads would help me. Thank you!
Hi,
The 5V from the 5V regulator that you are feeding to Vin is not high enough.
You are feeding Vin to a 5V regulator on the mega PCB, it needs at least 2V higher than 5V to work properly.
On the mega, unfortunately you cannot feed 5V into the 5V pin.
The USB 5V is fed to the board through some solid state switching so it can be connected to the 5Vin.
You can replace your 7805 with a 7809 to fix the problem.
Tom.... 
Thnks for the response. I fixed that by using an 8 v regulator still 6 V appears on the 5v pins. I'm thinking it maybe from the vibration motors.
flippomendes:
Thnks for the response. I fixed that by using an 8 v regulator still 6 V appears on the 5v pins. I'm thinking it maybe from the vibration motors.
Keep the motors de-activated and measure the voltage again - to see if that's true. If not, then see what happens if you put bigger smoothing capacitors on the regulator output. Otherwise, see what happens if you use a spare Arduino Mega. Always good to have spares for testing.
If the same issue occurs, then test the voltmeter or multimeter for measurement accuracy as well.
Hi,
I hope its only a diagram error, but the flyback diodes you have across your motors are back to front.
Also if you are supplying your motors from the output of the same regulator, you will need more than 10uF on the output of the regulator.
Try 100uF on the output and 0.1uF in parallel with it.
Can you post a picture of your project please, so we can see how your have layed out your wiring.
What is the power supply that you are feeding to the regulator.
Yes the motor noise could be the problem, place 0.1uF cap across each motor terminals.
What is the specs on the motors?
Thanks... Tom..
TomGeorge:
Hi,
I hope its only a diagram error, but the flyback diodes you have across your motors are back to front.
Also if you are supplying your motors from the output of the same regulator, you will need more than 10uF on the output of the regulator.
Try 100uF on the output and 0.1uF in parallel with it.Can you post a picture of your project please, so we can see how your have layed out your wiring.
What is the power supply that you are feeding to the regulator.
Yes the motor noise could be the problem, place 0.1uF cap across each motor terminals.What is the specs on the motors?
Thanks... Tom..
Thanks! I had my diode in reverse as you pointed out!
flippomendes:
Thanks! I had my diode in reverse as you pointed out!
So is the arduino 5V output putting out 5V instead of 6V now?
