When Raleigh released its Chopper wheelie bike in the 1970s, it became something of an instant classic. Though a fairly modern reissue went into production a little more than 10 years ago, it's an original 1973 MK2 that's been turned into the Synth Bike 2.0 mobile groove station – complete with analog synth, built-in speaker and wheel-based tempo control.

Serial synth tinkerer Sam Battle told New Atlas that the idea for the Synth Bike came to him about two months ago while cycling back home from a synth get together. His first attempt was a somewhat crude affair, slotting an Oyster card (an electronic ticketing card for public transport in London) into the spokes of the back wheel so that it hit a switch when the wheel turned and plonking some foil drum pads on the handlebars. The bike was mounted on a static frame and the electronics connected to Battle's modular synth, which is much too large for mobile use.

Version 1.0 was built around a BMX. A battered and bruised 1973 Raleigh Chopper MK2 bike became the unwitting host to the Synth Bike 2.0 mobile music machine.

"I was staring at my bikes in the corner of my room (I have a bit of a collecting problem, got 6 bikes just sitting there, just seem to gain them somehow)," Battle revealed. "I realized the Raleigh MK2 Chopper I had was perfect to build a synth into the handlebars as the space between each of the bars was massive, and just needed a face plate. Then after a couple of weeks of thinking I kind of just made a front panel of what I wanted it to do, and worried about the actual workings after that."

About a week's worth of evening wiring sessions later (and very little sleep), and the beat-making sonic machine was ready for testing in public. The electronics shopping list includes a drum machine courtesy of a Sparkfun WAV Trigger, some analog synth circuitry, a sampler, a digital oscillator, a Music From Outer Space Echo module, and a speaker at the back.

The roughly coffin-shaped control board mounted to the handlebars has more switches, dials, pads and knobs than you could safely play with while cycling, and there are more pads on the Chopper's top tube. All of the sequencing is digital, but there's an analog filter/VCA signal path. It also features eight Arduino Nano development boards.

"The main problem I had was power supply, as modular synths run on bipolar voltage and take a lot of current, I needed to find a solution, hence the Arduinos," Battle told us. At the moment, the power supply only gives around 10 minutes of play time, but there are plans to upgrade this in the near future (a battery unit from a mobility scooter is on the way).

A built-in clock can control the tempo of the sonic output, or the spin of the front wheel can determine the speed of the beat – so that the faster the rider pedals, the faster the generated music.

As to the question of why, Battle told us that the Synth Bike 2.0 was built just to prove to himself that it could be done. "Something inside me urges to make this stupid stuff, there's a lot of it, I'm surrounded by projects and silly ideas that don't work. It saps a lot of your money, so I'd watch out if anyone is looking to get into the whole creating stupid machines addiction."

The video below shows the Synth Bike 2.0 in action. The wires from the backpack lead to a multitrack recorder used to capture the live audio.

Source: Sam Battle

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