Hey, Mark, I have more EE type questions if you have a moment. You've been so helpful with this in the past despite saying you're not an EE, so I'm hoping you can give me some ideas about this one.

I was originally powering the arduino and the Betz board both with 5v from the pololu. 5v out from the pololu, goes to 5v on the Arduino, 5vin on the Betz board, and 5v input on the MAX232 chip.

But when I switched to 3.3v then I needed a 3.3v source of power. I found that when the arduino is getting its voltage from the 5v pin then it's not putting out 3v on its 3v3 pin. In order to make the Arduino put out 3v on that 3v3 pin, I needed to power it from the VIN pin or from the USB port.

So I switched it so that I was powering it from VIN and then all other 5v stuff is being powered from the Arduino's 5v pin as output. But that wasn't enough, for example the 5v pin was now not supplying enough voltage for my MAX232 to fire up (it needs 5 volts and now the Arduino wasn't supplying enouugh).

So I split the difference and powered the Arduino from VIN with 5v from the Pololu and also powered the MAX232 with 5v from the same pin of the Pololu. That works most of the time except when things are cold (literally cold in the car and the BlueGigaEmpeg assembly is cold). After things warm up it all works. But I need it to work when cold too.

the Arduino always works no matter what I do the problem is getting that 3v to the Betz board from the same power supply. When things work badly the Betz board reboots itself a lot. I think it's because of too little voltage from the 3v3 pin on the Arduino.

So I'm wondering if what I need to do is figure out how to supply that 3v3 myself instead of depending on the Arduino's voltage regulator to be good at the job of putting out 3 volts.

I don't want to put in a whole other power supply but I'm wondering if you have any ideas about other ways to supply those 3 volts. For instance, would another voltage divider work there, or should you only do a voltage divider for signaling and not for a power supply?

To complicate matters, I want a system which is compatible with debugging the arduino via its USB port, plugging the USB cable into the Arduino while the whole assembly is also plugged into the empeg (pololu powered by the 12v from the tuner connector).

Looking for ideas.