Prototyping Magic: Hands-on with the Wire-Free Jumperless Breadboard

At first glance, it feels like a joke: if you want to follow the success of the solderless breadboard, the electronics equivalent of the breakthrough that was the invention of sliced bread, you're going to have to remove the jumper wires too. Except nobody told Kevin Santo Cappuccio it was a joke — and the result is the Jumperless.

Designed to mimic the layout of a standard half-size solderless breadboard, with all the same connections, the Jumperless is powered by a Raspberry Pi RP2040 microcontroller and a matrix of switches. The latter are the secret to its success, making connections between rows and columns in place of the the usual flying-lead jumper wires you see tangling up breadboard projects.

But that's not all the Jumperless can do. Hiding behind those eye-catching LEDs is a surprisingly powerful platform for prototyping and experimentation — but is it really the best thing since the solderless breadboard?

Hardware

• Breadboard: 10-column, 30-row, two power rails
• Microcontroller: Raspberry Pi RP2040
• Expansion header: Arduino Nano or pin-compatible
• RGB LEDs: Two per row, one per power rail segment, one per expansion header pin
• Connectivity: Mini-USB 2.0, power and data
• Input/Output: 4× general-purpose, 4× analog inputs (1× ±8V, 3× 0-5V), 2× analog output (via Microchip MCP4822, 1× ±8V, 1× 0-5V)
• Extras: 12× WCH Electronics CH446Q crosspoint switches

The specs sheet for the Jumperless looks a lot closer to one for a development board than a breadboard. There's a good reason for that: it is a development board, albeit one designed with a very specific purpose in mind.

The on-board Raspberry Pi RP2040 microcontroller isn't there to run your code, but to host the firmware Cappuccio says he spends "every waking second" working to improve. It's this that handles everything from setting up the crosspoint switches to wire up your projects to measuring current draw or setting up an analog output — and the communication between the Jumperless and your host PC.

It also handles the surprising number of RGB LEDs festooned around the board. There are two per breadboard row, found in the middle of the five-hole sections either side of the dividing center line, one for each five-hole segment of the twin power rails — with separate LEDs for VCC and ground — and one each for every pin of the board's expansion header.

Said header is where you turn the Jumperless into a true development board: it's designed to accept an Arduino Nano or pin-compatible microcontroller, which is then free to communicate with the on-board RP2040. That opens up some interesting possibilities: it's possible, for one surprising example, for the Arduino Nano to reconfigure the wiring of the breadboard itself by sending a string over a UART bus — but we're getting ahead of ourselves.

Just because the Jumperless is designed to be jumperless doesn't mean it has to be. Beneath all those glowing lights and RP2040-powered smarts is a breadboard, and you're free to connect it up with jumper wires if you really wanted to. While that's arguably quicker than using Wokwi, the graphical circuit design and simulation tool, to design a project, it's also unnecessary: a relatively recent firmware update introduced support for "Probe Mode," which makes connecting breadboard rows as simple as poking them with a pointy needle.

Welcome to Wokwi

For a newcomer, the easiest way to get started with the Jumperless is to use Wokwi — the aforementioned graphical circuit design tool. After signing up for a free account, you simply create a new project and add a half-size breadboard mimicking the one on the Jumperless. Add the components of your choice and virtual jumper wires, and — optionally, but well-advised — use Wokwi's handy simulation feature to test things out.

The Jumperless comes with a software tool that acts as a bridge between your virtual Wokwi project and the physical version. Available for Microsoft Windows, Apple macOS, and any Linux distribution capable of running Python 3 and handling a couple of USB UART devices, the software lets you communicate with the Jumperless over a simple text-based user interface.

After you've designed your Wokwi project, you just copy the URL and paste it into the Jumperless tool — into one of eight selectable slots, allowing you to quickly flick between projects on-demand. Select the slot and the software reaches out to Wokwi, downloads the project, and converts it into a netlist before configuring the crosspoint switches accordingly.

You'll know if it worked, because all those RGB LEDs aren't just for show: connected rows are highlighted in matching colors, making it easy to see where each component should go. They don't match the wire colors selected in Wokwi, sadly, but that's a minor complaint. Impressively, they also update in near-real-time: make a change in Wokwi and hit save, and the Jumperless rewires itself in less than a second.

You're not just limited to wiring up basic components, either. Adding an Arduino Nano — or, in the firmware's latest update, an Arduino Nano ESP23, with more pin-compatible boards to follow — to the project lets you not only wire its pins wherever on the breadboard you please but even to write an Arduino sketch right in Wokwi, and have it flashed to the physical Arduino Nano installed in the Jumperless' expansion header automatically.

Advanced users

Using the Jumperless with Wokwi feels a little like magic. While, admittedly, you're still responsible for placing the actual components, being able to translate wiring changes to the physical breadboard in a single click is incredible — but that's far from the only thing you can do with the Jumperless.

The four analog to digital converter (ADC) inputs on the Raspberry Pi RP2040 are present and correct on the Jumperless, with three level-shifted to 5V logic. The fourth is shifted to ±8V — and all four are available to use in the Wokwi Logic Analyzer, along with a current sensing input that can be connected to any breadboard hole. This, of course, means that the Jumperless is not only jumperless but can be debugged without a physical logic analyzer too.

That's an impressive enough list of advanced features, but Cappuccio's not done there. The Jumperless also includes a two-channel digital to analog converter (DAC), with one channel shifted to 0-5V and the other ±8V. These are fully controllable by the user, and can be used with a waveform generator integrated into the firmware — good to 40kHz and above, Cappuccio says. The second channel of the current sensor is connected to the DAC's ±8V output, too, as a handy bonus.

We're not done yet, though. There's a small four-pin GPIO header to the top-left edge of the board, away from the main breadboard area. This can play host to add-ons, including a recently-designed needle-tipped probe — unlocking the ability to use the Jumperless entirely offline, with no host computer. Just connect a USB power supply or battery and the probe lets you make or delete connections at the push of a button: just pop the needle in the first hole followed by the second and the switches will be reconfigured automatically.

Add in the ability to switch between stored Wokwi project slots — made easier if you add a rotary encoder on the Arduino Nano header, to mimic a feature which is to be built into the next generation Jumperless — and you've got a powerful device. If you still need more, there's plenty of scope to build your own software for the Jumperless thanks to its simple text-based interface — a third-party Node.js-based graphical user interface is already in development.

The sticking points

That's not to say the Jumperless is perfect — if it were, Cappuccio would likely have a lot more free time. The firmware is under constant development, though primarily to add new features. The Python-based bridge software is functional and responsive, but surprisingly hungry: constantly polling for updates to Wokwi projects sees it redline two CPU cores.

There's no getting around the price issue, either. While a standard half-size breadboard will set you back a dollar, and a couple more for a decent selection of jumper wires, the Jumperless is $299 — unavoidably so, when you look at how much hardware is packed into the gadget. Even accounting for the fact it can, for some projects, replace a separate logic analyzer and benchtop power supply, that's a steep fee for entry into the Jumperless world.

But the simple fact is there's no competition. If you need the features the Jumperless offers — and it has a lot to offer those willing to experiment, from powering self-configuring synth patches to serving as a reverse-engineering platform for unknown chips, or even operating as a rudimentary EEPROM programmer — then it's the only device for you, regardless of price. This is true even given the hardware's limitations on routing complexity: the switch matrix isn't fully-connected but relies on smart routing, meaning that it's possible to breadboard a circuit it can't wire up — though we couldn't hit this theoretical limit during our testing.

That price also includes Cappuccio's time — the maker is responsive on both the Jumperless forum and social media, and the constant flow of firmware updates and new features proves his claim of focus on making the Jumperless as good as possible is no lie — and a no-quibble guarantee: if you don't like it, send your Jumperless back for a full refund. If you do something exciting yet inadvisable and somehow break it, Cappuccio even promises to send you the parts to get it back up and running — or even to repair it for you, free of charge.

For those tempted by a Jumperless but put off by the price, there is another option: Cappuccio has released the Jumperless design under the Weakly Reciprocal variant of the CERN Open Hardware License 2, while the firmware and software are published under the permissive MIT license. This means there's nothing to stop you making your own: the project's GitHub repository even includes production files alongside the KiCad project files, ready to be sent off to the PCB fab of your choice.

Conclusion

There's nothing quite like the Jumperless, although the recently-unveiled Sandwizz comes close — swapping some of the advanced features and handy RGB LEDs for common components integrated directly into the breadboard. The Jumperless is expensive, it's true, but for those who spend a lot of time chopping and changing the wiring of their prototypes it could prove invaluable.

For those who think the Jumperless doesn't go far enough, meanwhile, there's hope: the Jumperless V5 takes the concept and dials everything up to 11, not only adding the rotary encoder for project selection that is an optional extra on the current revision but extending the RGB LEDs to every individual breadboard hole — festooning the board with a total of 455 LEDs, enough even for a two-line scrolling text display or low-resolution video playback. Existing Jumperless owners will even be able to pick up the V5 at-cost, Cappuccio promises.

If you're happy with the current Jumperless design, though, and don't mind the price, it's unlikely you'll be disappointed. The Jumperless is the closest thing to magic you're likely to put on your workbench, and it's only getting better.

The Jumperless is available to buy on Cappuccio's Tindie store at $299, including a kit to assemble the probe; Hackster readers can get an extra ten per cent off with the discount code '7B9F76F6'. Full sources and design files are available on GitHub, while community discussions can be found on the Jumperless forum.