>>
>> current the on board regulator can supply.  Several props have
>> electromagnets and automotive relays being powered from the same wall
>> adapter using a fair amount of logic level mosfets with the gates
>> directly driven by Arduino output pins.  So far reliability has been
very good.

> It is refreshing to hear this as the owner had concerns about arduino
reliability.  I think you were more referring to the PSU but they are
connected.
> I am only using one and did the regulator test while it was powering 4
RFID readers and 1 ESP8266 and as I suspected was too much for the onboard
regulator.

To be clear, I didn't use the Arduino to power the accessories through its
regulator; I just shared the same power source with them with no extra
power conditioning for the board.  The ESP8266 I have needs about 100mA
when transmitting.  I believe the RFID readers I have use about the same
when the antenna is on.  So 500mA at a 7V drop through the 5V regulator is
3.5W.  That's a lot of heat for the tiny little thing on those boards.
Even a full size 7805 would want a heatsink on it.  Then that much current
through the 3.3V regulator is nearly another Watt.

I had some trouble selling "my guy" on using microcontrollers, but he
loves them now.
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.