Jumperless V5 is a breadboard where any point can be connected to any other with software-defined jumpers. RGB LEDs under each hole turn the breadboard into a display; paired with its assortment of routable analog/digital I/O, Jumperless V5 gives you real-time information about everything happening in your circuit and the ability to change it at a whim.

The four individually programmable ±8 V power supplies, five voltage/current/resistance measurement channels, and 10 GPIO can all be connected anywhere on the breadboard or the Arduino Nano header. Connections made with its matrix of 12 analog crossbar switches can be changed in just a few microseconds, so measurements and GPIO can multiplexed to cover the entire board simultaneously.

Jumperless V5 is like x-ray specs for electronics enthusiasts—it lets you see electrons flowing, capacitors charging, frequencies changing, and UART messages zipping, all right there on your breadboard.

Improving on the Original

V5 is a significant redesign of the original Jumperless. Having a few hundred people out there using Jumperlesses, sharing ideas, and writing their own apps gave us a long enough list of things to improve and upgrade. Now that the fundamentals are battle-tested, Jumperless V5 can add some even crazier new stuff like an ungodly number (445) of LEDs, a built-in rotary encoder/switch, daisy chain headers, individually programmable power rails, and an isolated, always-on probing system.

These additions may seem minor, but they fundamentally change how using a Jumperless feels. It’s intuitive enough that it quickly just becomes "part of your brain" in the same way your computer does. And it’s easy to forget this isn’t how prototyping stuff on a breadboard has always been.

The App

The desktop app allows you to assign up to 8 Wokwi projects to separate slots that are polled for changes and automatically updated on the Jumperless V5 (within half a second of clicking save). Or if you don’t want to use Wokwi, it simply acts as a regular terminal emulator like PuTTY, xTerm, Serial, etc. You could also just use any of those; the menus are sent and handled on the Jumperless itself, and the Jumperless desktop app just adds automatic firmware updates, Wokwi polling, and arduino-cli for flashing code from your Wokwi sketch to the Arduino via a single USB cable.

Features & Specifications

• 4 x 12-bit DACs (MCP4278) buffered and shifted to ±8 V through high current op amps (2x L272D)
• 3 x 12-bit ADCs (built into the RP2040) double buffered and level shifted (2 LM324) to read ±8V
• 2 x 12-bit current/voltage sensors (INA219) which can also be used to measure resistance
• 4 x 5 V logic level GPIO (MCP23S17)
• 6 x 3.3 V logic level GPIO (RP2040) which can also be hardware I2C, UART, or SPI
• 1 x ±8 V op amp noninverting buffer (LM324)
• 2 x 14 pin daisy chain headers on either side to pass eight analog signals + SPI + Power to another Jumperless
• A probe to select rows without affecting connections (TRRRS jack with I2C)
• A rotary encoder / switch (SIQ-02FVS3)
• 445 addressable RGB LEDs (XL-1010RGBC)

Included Probe

Jumperless V5 uses a string of 92 ±0.1% precision resistors in a huge voltage divider and one of the ADC channels to sense which number the probe is poking. The probe itself is very simple, just a button, an LED, and a pokey needle to touch the sensing pads. It connects to the main board with a TRRRS 1/8-inch audio jack. It also has I2C and power available for future hacking purposes (in case someone wants to stick an OLED on the probe, the code already sends signals for an SSD1306 display).

If you misplace your probe, its design allows you to plug in any random 1/8-inch audio cable and poke out connections with the tip.

Serial/I2C/SPI/MIDI

Jumperless V5 can sniff or write any UART, I2C, SPI, or MIDI signals on the board. It can be set to either print whatever it reads on the breadboard LEDs, turning the Jumperless into a serial monitor, or show up as two USB devices on your computer and give you bidirectional communication through that other port.

Open Source

Jumperless V5 is designed to be infinitely open-source and hackable. Want to make 10 of these with a mini USB port for you and your friends? Let me know, and I’ll double-check everything when you’re putting in the PCB order to make sure all the parts are placed correctly. I’ll even send you the custom spring clips.

As of right now, you can access KiCAD files for the schematic and PCB design in our GitHub repo.

Interested in This Project?

You can sign up at the top of this page to be notified when the campaign launches and to receive other updates. We provide useful information only, and you can unsubscribe at any time.