Go Down  Topic: DFROBOT MIDISHIELD (Read 549 times) previous
topic - next topic   Apr 21, 2013, 12:21 am Last Edit: Apr 21,
2013, 12:31 am by Trazman001 Reason: 1   I have a arduino uno
and a DFROBOT midi shield. I and I'm using it as a midi
controller. it works as long as I use a USB cable to my computer
but it won't run on a 9V battery. I have the battery connected
to the uno on the bottom (direct 9V) it powers the uno but not
the DFROBOT midi shield.   That really sounds quite odd.  The 9V
passes through a linear regulator on the Uno then the regulated
5V from that goes through a switch that automatically selects
the regulated power in preference to the USB if both are
present, or the USB only if there's no regulated source.  If the
9V powers the Uno then you'd presume all that is functioning
correctly.  Downstream of that switch circuit it's just the 5V
rail so there's no difference between both circuits.  If there
is power present either should get to your shield.  Looking at
the board layout of the DFRo