The current DingBot schematic.
This version uses a variable LDO regulator; a fixed-voltage version would be fine, but this was what I had on hand. The diode-drop version I was using before just wasn’t stiff enough.
R1 and R2 are 1%, to ensure the output voltage is within the XBee’s range; they can be 1/8W, because very little current flows through them.
The regulator needs no heat sink; the junction is typically around 50 °C in normal operation.
C2 and C3 are tantalums because they fit on the board easier, and for long life. C1 is any convenient type for bypassing the PIC.
IC2 should be an XBee with wire antenna in one unit, and an XBee-Pro with external antenna in the other unit. In practice, this seems to be just right for getting good reception throughout my house; two XBees don’t cut it, and two XBee-Pros are overkill.