jremington:
You can modify the circuit shown here Arduino Playground - HomePage to work at 134.2 kHz. The coil will need to have fewer turns so that the combination of L1 and C1 is "resonant" at 134.2 kHz instead of 125 kHz. There are standard formulas for the resonant frequency as a function of the coil inductance (which in turn you can estimate from the size and number of turns) and the capacitance of C1. Google "LC resonant frequency" and "coil inductance formula" to learn more.
Thanks will dig into it now. Regarding that circuit, on the playground l1 (the only) and is it c1 are thr ones determining the resonance. (There are 6 capacitors)
Also, theres a line of code that states changing if using 134: I need to change l, c and the software value?