I just want to say sorry from the begining because this does not relate to the arduino.
I have an mp3 player that runs on a 1.5v. Triple A batt, it kinda kills the batt quick (about 8 hours) and I wanted to take resistors and make my car batt power up the mp3 player.
Some one told me just to take resistors (220 and 15ohm) and that aould give me 1.5 but I tryd that and it didn't work
I bought a 5v regulator for a more stable voltage but resistor do I put inline to reduce the 5v down to 1.5??
The mp3 spec...
1.5v
Start up .090ma
Playing music .045-0.50 mA
Is this possible? And again I'm sorry for this topic not being arduino related but thanks in advance for any info =]
Once the proper regulator resistors are calculated as shown in the data sheet and installed then the regulator output will be just like a battery that nevers runs down, no resistor needed between the regulator output and your MP3 device.
I've just joined too and happily I can give you a full answer because I've done it.
You need a LM317 Voltage regulator. I'm using the LM317T which is in a TO220 package without a heatsink but it's very likely that a smaller TO-92 version would do just as well (100mA - my mp3 uses about 40mA)
You then need two resistors - you'll find a calculator here: http://www.reuk.co.uk/LM317-Voltage-Calculator.htm
The datasheet also recommends a couple of capacitors but you will probably find that it works fine without them.
One thing I noticed when I did this was that I got a lot of noise which I thought was due to my power source. This may have been the case but I solved it by using a different mp3 player. I guess the internal filtering of some cheaper mp3 players is better than others.
