Hi,
My problem is really similar to this old topic:
https://forum.arduino.cc/index.php?topic=576321.0
I have Arduino Uno R3 board and Arduino Motor Shield (L298).
When I connect the board and the shield (alone, without any wiring or any motor used) the voltage collapses. It looks like it is short-circuited. The problem is caused only by the IOREF Pin.
The Arduino Uno R3 works well alone. I have not changed the jumpers.
Any advice would be grateful!
Thanks and regards.
Have you verified that it is a short with a ohmmeter?
Thanks for your answer.
No.
I measured the voltage between 5V spin and the ground. It is 5V without shield and it is only 1.5v with shield.
How can I fix this?
Get an ohmmeter and measure. And/Or take some 8x magnifying glasses and check the traces, most likely there's just some solder bridge.
I went back to the store and I changed the shield. The new shield behaving the same way. So the problem should be in the Arduino board but that is working properly alone.
The HEF4077BT IC heats up in a second. I took 8x magnifying glasses and I cannot see any problem or damages.
Ok ... now comes the fun part: on one hand, there is no guarantee that the shields are working. 2., is it a shield or something else? In both cases, get the schematics, check if the wiring is correct. As I don't see the curcuit I cannot tell you more.
Thanks for your help. Maybe I was not able to explain it correctly. It is no wiring at all. I just put together the two parts like this.
https://cdn.instructables.com/FX2/YS42/H05NSWPA/FX2YS42H05NSWPA.LARGE.jpg
and I gave the power like this:
https://cdn.instructables.com/FH0/3CF6/H05NHAOH/FH03CF6H05NHAOH.LARGE.jpg
I didn't change the jumpers. This is my 2nd shield. It should be some compatibility issue or...
What should I do?
IMO the shield is not working. However, you could start this way: disconnet shield and arduino, add 1 (!) ground wire from arduino to shield. Add a second wire on +5V. If it works, ok, on to the next ground pins. Always check if it's still working. Add the Vin wire (this can be interesting), and so on ... this way youll find whom to blame.
Are you plugging the shield in the right way around ...
The results you get are without a motor connected ? ( this should be the first step)
I did this. The system works well until I add the IOREF pin. IOREF pin is 5v.
Are you plugging the shield in the right way around ...
Yes.
The results you get are without a motor connected ? ( this should be the first step)
Yes. Like this:
https://cdn.instructables.com/FH0/3CF6/H05NHAOH/FH03CF6H05NHAOH.LARGE.jpg
Stupid me. Ok, the obviouse easy solution is to simply cut the IOREF pin from shield to Arduino. Or check the traces on the arduino board, maybe C4 is short.
Edit: Please check the voltage on the arduino IOREF.
Please check the voltage on the arduino IOREF.
+5v.
Ok, the obviouse easy solution is to simply cut the IOREF pin from shield to Arduino.
I would do it but I red here
https://forum.arduino.cc/index.php?topic=576321.0
it causes other problems...
What problems? Is it used for something on the shield? It's just connected to A_ref on the AVR.
Please check the resistance tom AOREF to +5 on the Arduio without power connected. it should be > 100k. If it's < 1k, then there's a short from +5V to IOref, that you might want to hunt down.
Thanks for your answer.
Please check the resistance tom AOREF to +5 on the Arduio without power connected. it should be > 100k. If it's < 1k, then there's a short from +5V to IOref, that you might want to hunt down.
It is no resistance at all. your hypothesis is correct. What should I do now?
I believe I found the problem:
https://forum.arduino.cc/index.php?topic=584986.0
Either ignore it and cut the wire (tht's what I would suggest), or get the schematics and follow the traces. Loosing IOREF is of no concern, it's a myth that it causes problems. All that happens is that you are bound to the AVR internal reference voltages, that' 5V, 2.56V and 1.1V. If you can live with that, then call it a day.
Thanks for your reply. I believe Slevigen's solution is the best solution (Arduino Uno and Motor shield IOREF power fail - Motors, Mechanics, Power and CNC - Arduino Forum). He "turned IC4 around" but I don't know how to repeat his solution.
I learned with this project that I should buy original Arduino parts and shields. This unknown products just causes problems and time-loses. I will go back to the store and I will ask an original part.
That's definitly the betst thing to do.
Interestingly no-one asked the obvious:
What do you have for power supply, and how much current does that motor take?
Where's the link to the information your specific shield?