License to Spill

Have you seen those bumper stickers about honking your horn? No, not those ones! Get your mind out of the gutter, this is a family-friendly website! I mean the recent meme bumper stickers that say something along the lines of “Keep honking! I’m listening to” something or other, where the something or other is typically oddly specific or otherwise humorous. Anyway, if you have not seen one yet, then you are all but guaranteed to see one next time you are out for a drive because that is how these types of things always seem to work.

Hardware hacker extraordinaire Guy Dupont, for one, is kind of obsessed with these bumper stickers. But he is also tired of living a big huge lie of a life. You see, these are just plain old stickers, so they may be correct about as often as a broken clock, but in general you have to live with the knowledge that you are not actually listening to what you claim to be listening to. Sad.

To right this wrong, Dupont developed what he calls the Bumpin’ Sticker, which is actually not a sticker at all, but rather a high-definition display and handful of electronics that show other drivers what you are listening to in real-time. This could burn you, of course, if you “accidentally” find that "Friday" by Rebecca Black, or anything by Justin Bieber, makes its way onto your playlist. But hey, at least the Bumpin’ Sticker lets you live with a clean conscience.

The centerpiece of the build is an 11.3-inch, 440 x 1920 pixel HDMI display. A Raspberry Pi Zero 2 W single-board computer is used to drive the screen, and a Particle Boron development board was included for internet access on the go via cellular networks. The components were hot glued together before being encased in heat-shrink wrap as a makeshift weatherproofing solution. A window was cut into the heat-shrink wrap to expose the screen, and powerful magnets were used to keep the device in place on the back of the vehicle (so far).

The Bumpin’ Sticker was powered by splicing into the power source for the car’s backup camera. This source had the added benefit of only being on when the car was running. That prevented the electronics from draining the vehicle’s battery while it was not in use.

Dupont utilized a platform called Val Town to write and deploy TypeScript applications that carried out a few essential functions. One of these functions scraped his public Last.fm profile to find what he was currently listening to. This web service was queried with the Boron’s cellular data connection, which then passed the information along to the Raspberry Pi via Bluetooth. The Raspberry Pi then ran another Val Town script, but did so locally. This script generated a PNG image, including the name of the currently playing song, to display on the screen as an electronic bumper sticker.

So far the Bumpin’ Sticker is working just as Dupont had hoped. While the hardware is rock-solid, the weatherproofing and magnet attachment may not be. But until it falls off or suffers irreparable water damage, Dupont plans to broadcast his musical preferences to everyone else on the road with this unusual gadget.