I would like to use a “Bluetooth Modem - BlueSMiRF Silver” module with a power supply between 6 and 12V (depending on the kind of batteries used, and how fresh they are).
Is it possible to use a simple zener regulation? What resistor value should I use to cover all voltages? And what power for resistor and zener?
Zener regulators are viable only for very low current and constant-current loads such as 10mA or so. Otherwise you need a high wattage resistor/Zener and the design becomes silly as compared to using a regulated power source or using a one-chip regulator.
Yes, I know… Here the power won’t exceed 1W, I think. The idea is to have all things directly wired on the module or on the wires. Using a regulator will need a little PCB, to put all the capacitors. Unless you have a simple design?