Hi,
I just picked up my Arduino Uno R2 with three shields plugged into it, all powered from a wall wart. The temp on the underside of the Arduino at the location of the voltage regulator was almost too hot to the touch within a few seconds. The shields are, motor shield, micro SD shield, color LCD shield. The whole stack is being powered via an external wall wart power cube putting out 7.5V up to 1.5 amp. I've been running this stack this way for several days, just to see if it is stable. No external connections to motors etc. are connected at this time.
Is there anything I can/should/must do reduce the hot spot problem associated with the voltage regulator? I'm planning to add additional shields to the stack in the future so if it's already too hot to handle this could become problematic. The overall stack of boards is intended to run independantly for long periods operating a remotely controlled observatory. Is there a URL location where one can get power consumption rating for various shields so that I can estimate power consumption. Has anyone designed or built an amp meter setup to measure current going into the voltage regulator. Would using an external 5V regulated power supply powering the 5V pin eliminate the regulation burden the votage regulator is experiencing now? All suggestions are welcome.
Norm
The UNO uses a linear voltage regulator, meaning the 2.5V from 7.5V to 5V are transformed into heat. For high-current application a switching DC/DC converter is much more appropriate as it looses much less power and is converting most of it's input to the output voltage. You can use an external regulator and feed the 5V directly to the 5V pin, but usual power supplies (wall adapters) don't deliver a stable enough voltage. There are Arduinos that include a DC/DC converter already (p.e. the Iteaduino V.2.1).