I have this motorshield V1 hooked up to an UNO, programming it via USB, then putting in the link to power it off the 12V supply to the shield.
That all went well till recently when the link would no longer power the UNO.
I am told that I probably blew something in the power routing.
So, couple of questions:
The UNO has quite a few 5V pins but they don't all seem to connect together (not on the "same" bus).
And none connects directly to the 5V USB pin. WHY?
Also, there is the Vin pin which CAN take a 12V regulated supply and turn it into 5V. So why is the power link on the motor shield (which is frequently powered by more than 5V) not connected to the Vin instead of 5V????
And finally, why can't I just take the 12V from the power link and bridge it to Vin to power the UNO, and not bodgy around with a 7805 and all that.
I have ONLY 12V available on this project, and NO USB so.......
Yer not reading the schematic right Aussiewill. If a pin (or other circuitry) has an arrow pointing to "+5V", it's all the same 5 volt rail. Yes you can put 12 volts into VIN and power your Arduino. You didn't say what motor shield you have, so I can't offer any advice.
Thanks for that advice.
I figured it SHOULD be safe but wasn't going to take chances.
Yes, I did state V1 (version 1), so if you have an answer to the question "why not connect the power link to Vin" I'd love to have it.
OK, took all that on board, but have now found out that supplying my 12V to Vin doesn't help.
Looks like I probably blew the voltage regulator????????
So, next question:
Seeing that everything DOES work with USB and 12Volt (to motor shield), can I rig up a 7805 to feed the 5 Volt pin (any of them).
The 5V rail should be AFTER the regulator???? Or not???
Tried to work that out from the UNO Rev3 circuit, but no luck.
The only one I've got is the UNOV3PDF.png. Basically just gives pin outs etc.
Looking for more help. I know UNO's aren't that expensive but I HATE scrapping anything that can be made to work.
When I said I didn't understand I meant how exactly the board circuitry is laid out.
As I said, I've only been able to locate that UNO3VPDF.png schematic which is great for all the pin outs etc. but doesn't show the INTERNAL layout.
But that doesn't matter so much now.
It's really not that hard to replace the onboard regulator. I had to do it as a result of miswired end-stops on my 3d printer. There are simple ways to remove SMD parts (Like CHIPQUIK) and you can buy the exact replacement from places like Digikey.com and Mouser.com or Farnell.