I'm designing a setup for a travelling nature exhibit for a museum. You push one of 3 buttons, and it plays a sound file. I'd like the setup to be self contained and not need an external power supply in case they want to set up away from an outlet.
The SparkFun MP3 Trigger by itself has a rated "idle" power consumption of 45 mA.
This is too high to be running all the time on a battery, so I'd like to figure out a way to put it to sleep when no-one's around. Even with a 2.2Ah battery I still run out of juice before 3 days. If the staff turn the power off at the end of the day it only doubles endurance.
I've seen some setups where an Arduino is put into low power sleep mode, with an interrupt tied to a PIR (which only uses 1-5mA), so it should only wake up when someone walks near the exhibit. I understand this greatly increases the endurance.
My question is if I have the Arduino controlling the MP3 Trigger will the trigger only draw power when the Arduino is awake?
You can make it do that. Best is a standalone design so no regulator, power LED, USB interface, just the chip, 8 MHz xtal & 22pF caps (or resonotor, or internal), 10K reset resistor, couple 0.1uF caps.
Go into power down sleep mode, any button press is diode ANDed to hardware interrupt.
On button press, wake up, read the button, turn on P-channel MOSFET to power MP3 module & speaker amp, select an input, when done playing reverse all the steps.
Some other MP3 modules:
I have several of these, have only tried one, was easy to use. http://www.mdfly.com/index.php?main_page=advanced_search_result&search_in_description=1&zenid=26152301373bc97a159d507a7ac152bb&keyword=mp3
I just got a couple of these but haven't tried them yet.
CrossRoads:
You can make it do that. Best is a standalone design so no regulator, power LED, USB interface, just the chip, 8 MHz xtal & 22pF caps (or resonotor, or internal), 10K reset resistor, couple 0.1uF caps.
Go into power down sleep mode, any button press is diode ANDed to hardware interrupt.
On button press, wake up, read the button, turn on P-channel MOSFET to power MP3 module & speaker amp, select an input, when done playing reverse all the steps.
Without the regulator, what would be the best kind of battery setup to use? I was initially looking at a 12V 2.2Ah, but without a regulator I'd need something around 4-6V right?
