Introduction: Upgrading a Niftymitter 0.24 PCB to Guts V0.3
Niftymitter is an open source short range FM transmitter.
Here's how to add in the volume control to the v0.24 board to make it into v0.3 guts for the Niftymitter Home and Gig.
Step 1: Solder in the Pot
Take the 50k potentiometer (pot) and attach 40mm lengths of wire to each of the legs.
Using a craft knife, carefully cut the trace between R1 and R2 (the 10k resistors at the line socket) and C1 (the electrolytic capacitor).
This image shows the underside of the PCB.
Solder the wire from leg 1 of the pot to the board at the pad where R1 and R2 join. Solder the wire from leg 2 to the negative of C1. Solder the wire from leg 3 to the ground.
Step 2: Glue the Pot Into the Board
Make up a spacer to build the pot up to the level of the outer surface of the housing. I did this in balsa wood, cardboard would do equally. The spacer should be 10mm high x 6 wide x 3mm thick.
Hot glue the pot onto the top of the spacer first. Place the pot in the hole of the middle hole of the housing, apply some glue to the bottom of the spacer and offer up the board to it, taking care to make sure the board fits within the appropriate area of the housing. The spacer should sit in between C3 and R1 - it is best to check this before glueing. With the blobs of hot melt included, the pot's base should be 13mm off the circuit board.
Step 3: Assemble the Housing
Assemble the circuit box housing as per v0.24.
Currently the hole for the pot is a bit too smaller so carefully enlarge this with a craft knife.