Circuit Locution

Probe: A simple probe made from two jeweler’s screwdrivers wired together is sufficient for simple bending. A safer (for you and the instrument) and more versatile tool can be made from a multimeter, a footswitch, and a potentiometer. See Advanced Probe.

Multimeter: Essential for any but the most basic of bends. Reading the voltage between points of a bend can tell you if it is safe or if it will fry the instrument. Reading the Ohms of a resistor or potentiometer can suggest other values to replace it with. Some complex bends involving feeding data into a sound chip can only be made within a very narrow range of resistance values, so reading a potentiometer to determine these values is vital. Fortunately, multimeters are cheap – a sufficiently accurate digital multimeter can be had for under $10.

Soldering iron: To make any bend permanent, you’re going to need to solder. Invest in a good soldering iron to save yourself a lot of trouble. It’s also useful to have a desoldering pump (aka “solder sucker”) or some desoldering braid, for when you wish to remove solder or components.

External speakers: Most toys have cheap, flimsy 2″ or 4″ speakers. To really know an instrument’s range, you need to replace it with a line out and run the sound into a set of decent speakers or an amp. A decent pair of computer desktop speakers works well as both amplifier and speakers and can be bought at most thrift shops for under $10.

Hot glue gun: When adding components like switches or dials to an instrument, it’s often hard to find space on the existing circuitboard to securely place them. A hot glue gun (and super glue, if you have a good surface to attach to) can secure most light-use components. For heavier-use items, you’ll want to find a way to encorporate screws or solder. A dab of hot glue also makes a good insulator, keeping extra wires from making undesired contacts.