Nothing spoils your mood quite like your windscreen wipers not feeling it when the beat drops. Every major car manufacturer is focused on trying to build the electric self driving vehicle for the masses, yet ignoring this very real problem. Well [Ian Charnas] is taking charge, and has successfully slaved his car’s wipers to beat of its stereo.

Starting with the basics, [Ian] first needed to control the speed of the wiper motor. This was done using a custom power supply adapted from another project. The brain of the system is a Raspberry Pi 3B+ which runs a phase locked loop algorithm to sync the music and the motor. Detecting the beat turned out to be the most difficult part of the project, and from the research [Ian] did, there is no standard solution. He ended up settling on “madmom“, a Python audio and music signal processing library, which runs a neural net to detect the beat in real time. The Raspi sends the required PWM and Enable signals to an Arduino over serial, which in turn controls the power supply. The entire system was neatly integrated in the car, with a switch in the dash that connects the motor to the new power supply on demand, to allow the wipers to still be used normally (and safely).

[Ian] filed a provisional patent application for the idea, and will be putting it on auction on eBay soon, with the hope that some major car manufacturer would be interested. For older cars, you can shove an Arduino into the stereo, or do a super cheap bluetooth upgrade. Check out the video after the break.

There is no question that steering wheel mounted controls are super convenient. Reaching all the way over to the dashboard to change a radio station is so 1990’s. An ever-increasing percentage of new cars are coming equipped with steering wheel controls for the stereo, however, you’ll lose the button control if you change out the stock head unit to something a little higher in quality. Sure, there may be an adapter readily available for your car/stereo combination, but there also may not be. [Ronnied] took the DIY road and made his own adapter.

The first obstacle for [Ronnied] was to figure out the wiring on the steering wheel controls. After some poking around he found that there were only two wires used for all of the control buttons, each button only changing the resistance between the two wires. The button states could easily be read by using an Arduino’s analog input. A Pro Mini model was chosen for its small size as it could be housed in the radio compartment of the dash.

The next step was getting the Arduino to control the aftermarket head unit. [Ronnied] did some research regarding JVC’s Stalk digital control interface but came to the conclusion that it would be easier to direct wiring the Arduino outputs to the appropriate spot on the head unit’s circuit board. To do this the button for each function that would also be represented on the steering wheel was traced out to find a common point on the circuit board. Jumper wires soldered to the circuit board simply allow the Arduino to emulate button pushes. To ensure that the head unit buttons still work in conjunction with the steering wheel buttons, the Arduino would have to keep the pins as inputs until a steering wheel button was pushed, the pin changed to an output, the signal sent and the pin changed back to an input. This feature was easily created in the Arduino sketch.

Video below.