A resistor decade
box in pots

A ‘decade box’ is a simple instrument for easily changing values of components during prototyping. ResPot is a fancy resistor decade box where values are set manually using a wire.

Assembly and usage

The project comes with the following components:

As you can see we supplied five PCBs and six different resistor values. Depending on which range you decide to use, you can get 1-99,999Ω or 10-999,990Ω.

You actually only need nine resistors per PCB, so there’s one spare. Enjoy. On the ‘copper’ side of the board you can see how the circuit board and holes are connected. Use that to determine how you’d like to connect the LEDs. You can choose to have either side be the ‘front’.

The value of the resistors we supplied you are accurate to 1% of the ‘ideal’ value. That error will either stack up cancel out depending on the direction of the error. This deviation from the ideal value is noticeable particularly in the higher values, of course, but ‘parasitic’ resistance (from the wires mostly) are more noticeable at the lower values.

Further information

ResPot is an open source design, as is most of our work. You can find the design files for the hardware and packaging at our GitHub repository. You can edit the design files using our own PCB design open source software, PCBmodE.

ResPot was Project #30 of the Boldport Club. If you'd like to purchase a kit, become a member and add one to your order through the shop.

The PCBs were lovingly made by Eurocircuits.

Community contributions for this project are on our community site.