Learning To Speak Peloton

Recently [Imran Haque]’s family bought the quite popular Peloton bike. After his initial skepticism melted to a quiet enthusiasm, [Imran] felt his hacker curiosity begin to probe the head unit on the bike. Which despite being a lightly skinned android tablet, has a reputation for being rather locked down. The Peloton bike will happily collect data such as heart rate from other devices but is rather reticent to broadcast any data it generates such as cadence and power. [Imran] set out to decode and liberate the Peleton’s data by creating a device he has dubbed PeloMon. He credits the inspiration for his journey to another hacker who connected a Raspberry Pi to their bricked exercise bike.

As a first step, [Imran] step began with decoding the TRRS connector that connects the bike to the head unit. With the help of a multi-meter and a logic analyzer, two 19200bps 8N1 RS-232 channels (TX and RX) were identified. Once the basic transport layer was established, he next set to work decoding the packets. By plotting the bytes in the packets and applying deductive reasoning, a rough spec was defined. The head unit requested updates every 100ms and the bike responded with cadence, power, and resistance data depending on the request type (the head unit did a round-robin through the three data types).

Once the protocol was decoded, the next step for [Imran] was to code up an emulator. It seems a strange decision to write an emulator for a device with a simple protocol, but the reasoning is quite sound. It avoids a 20-minute bike ride every time a code change needs to be tested. [Imran] wrote both an event-driven and a timing-accurate emulator. The former runs on the same board as the PeloMon and the latter runs on a separate board (an Arduino).

The hardware chosen for the PeloMon was an Adafruit Feather 32u4 Bluefruit LE. It was chosen for supporting Bluetooth LE as well as having onboard EEPROM. A level shifter allows the microcontroller to talk directly to the RS-323 on the bike. After a few pull requests to the Adafruit Bluetooth libraries and a fair bit of head-banging, [Imran] has code that advertises two Bluetooth services, one for speed and another for power. A Bluetooth serial console is also included for debugging without having to pull the circuit out.

The code, schematics, emulators, and research notes are all available on GitHub.

A Pull Chain To End Your Zoom Pain

Yay! Another videoconference call is in the books, so that must mean that it’s time to fumble around awkwardly for the hang-up button with a fading smile. [lanewinfield] knew there had to be a better way, and looked to the pull chain switch for salvation. Sure, this could just as easily be a button, but what’s the fun in that? Besides, few buttons would be as satisfying as pulling a chain to a Zoom call.

The pull chain switch is connected to an Adafruit Feather nRF52840 Express that’s emulating a Bluetooth keyboard. Firmware-wise it sends command + F6, which triggers an AppleScript that manually exits and and all Zoom calls and kills Chrome tabs pointed to meet.google.com. He’s using Apple’s hotkey wizard Alfred, but this could be handled just as easily with something like AutoHotKey.

Pull chain switches are neat little mechanisms. The chain is connected to a cam that engages a wheel with copper contacts on half the outside. When you pull the chain, the wheel moves 90° and the wheel contacts connect up with the fixed contacts inside the housing to make a connection. Pulling the chain again moves the wheel which slides to the half without the contacts. Check it out in the video below.

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Sims-Style Plumb Bob Broadcasts Your Mood

While there are a lot of objects from the Sims that we wish were real, we probably wish more than anything that everyone had a mood indicator hovering above their heads at all times. It would make working from home go a lot more smoothly, for instance. [8BitsAndAByte] made this Bluetooth-controlled plumb bob as part of their Sims Halloween costume, but we think it has real day-to-day value as this pandemic wears on, either as a mood ring or a portable free/busy indicator.

The hardware is about as simple as it gets — an Adafruit Feather nRF52 Bluefruit controls a pair of NeoPixel rings, one for each half of the translucent 3D-printed plumb bob. Power comes from a 500mAh battery, and all the electronics are situated inside of an attractive hat. Check out the build video after the break.

There’s more than one way to use color to convey information. This seven-segment temperature display does it with thermochromic film.

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Mirrored Music Machine Reflects Circadian Rhythms

Interactive artist [Daric Gill] wrote in to share the incredible electronic sculpture he’s been working on for the past year. It’s called the Circadian Machine, and it’s a sensor-enabled mindfulness music-and-lights affair that plays a variety of original compositions based on the time of day and the circle of fifths. This machine performs some steady actions like playing chimes at the top of each hour, and a special sequence at solar noon.

This cyberpunk-esque truncated hexagonal bi-pyramid first geolocates itself, and then learns the times for local sunrise and sunset. A music module made of a Feather M4 Express and a Music Maker FeatherWing fetches astronomical data and controls the lights, speakers, and a couple of motion sensors that, when tripped, will change the lights and sounds on the fly. A separate Feather Huzzah and DS3231 RTC handle the WiFi negotiation and keep track of the time.

On top of the hourly lights and sound, the Circadian Machine does something pretty interesting: it performs another set of actions based on sunrise and sunset, basically cramming an entire day’s worth of actions between the two events, which seems like a salute to what humans do each day. Check out the build notes and walk-through video after the break, then stick around for the full build video.

The internet is rife with information just begging to be turned into art. For instance, there are enough unsecured CCTV cameras around the world with primo vantage points that you can watch a different sunrise and sunset every hour of every day.

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Bluetooth Takes Keyboard From DIY To Super Fly

They say you should never cheap out on anything that comes between you and the ground, like tires, shoes, and mattresses. We would take that a little further into the 21st century and extend it to anything between you and work. In our case, ‘buy nice or buy twice’ includes keyboards and mice.

[Marcus Young] is a fan of ortholinear ergonomic comfort, but not of cables. He gave [adereth]’s dactyl keyboard some wings by using a Bluetooth micro, and the Pterodactyl was born. Of course, the two halves still use a TRRS cable to communicate, and wires are required to charge batteries, but it’s the principle of the thing.

That’s not all [Marcus] did to make the dactyl his own — it also has a modified full-fat base that gives him all the room in the world to wire up the keyswitch matrix compared to the original streamlined design.

Instead of the usual Teensy, Pro Micro, or Proton-C, the pterodactyl has a Feather 32u4 in its belly. [Marcus] is clacking on Holy Panda switches which we’ve been meaning to try, and individual PCBs for each switch, which seems like it might negate gluing the switches in place so they survive through keycap changes. Check out [Marcus]’ write-up to see what he learned during this build.

This isn’t the first modified dactyl we’ve seen flying around here, and it won’t be the last. Here’s one with a dual personality — both halves can work together or alone.

Via r/mk

Adora-BLE Synth Wails Without Wires

Isn’t this the cutest little synth you ever saw? The matching sparkly half-stack amp really makes it, visually speaking. But the most interesting part? There’s not a wire in sight, ’cause [Blitz City DIY]’s futuristic rig sends the bleep boops over Bluetooth LE.

Hardware-wise, both the synth and the amp are fairly simple. Underneath each of those cute little printed keys is one of those clicky momentaries that usually come with bright button caps in primary colors — the keys themselves just press-fit over the tops. All twelve ebonies and ivories are connected up to an Adafruit Feather, which communicates over Bluetooth LE to a CircuitPlayground Bluefruit (CPB) in the amp. Each time a note is played on the synth, its corresponding color circles comet-like around the CPB’s NeoPixels, which shine through the amp’s speaker grille.

The super interesting part is that all the hard work is happening in the code. Both boards have the same array of colors in rainbow order, and the CPB has an array of tone frequencies that match up one for one with the colors. For every note played, the CPB looks up the color, swirls it, and plays the note. If you want to build one, this project is wide open — [Blitz City DIY] even made a learn guide with all the dirty details. Be sure to check out the demo and extended walk-through after the break.

More in the market for making a computer keyboard? Just grab the nearest ESP32.

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Arduino Handheld Game System Gets A Grip

With little more than an Arduino, an OLED display, and some buttons, it’s easy to build your own faux-retro game system. There’s even a growing library of titles out there that target this specific combination of hardware, thanks in no small part to the Arduboy project. But unless you’re content to play Circuit Dude on a breadboard, at some point you’ll probably want to wrap the build up in a more convenient form.

Like many that came before it, the OLED handheld created by [Alex Zidros] takes inspiration from a Nintendo product; but it’s not the Game Boy. Instead, his design is based on a 3D printed grip for the Switch Joy-Cons that he found on Thingiverse. After tacking on a holder for the PCB, he had the makings of a rather unique system.

We especially like the offset SSD1306 OLED display. Not because we think a game system with an asymmetrical layout is a particularly sound design decision, but because it gives the whole build a rather cyberpunk feel. When combined with the exposed electronics, the whole system looks like it could have been cobbled together from a futuristic dumpster. Which is high praise, as far as we’re concerned.

Opposite the display is a LiPo pouch battery that [Alex] says was liberated from a portable speaker, and down below is an Adafruit Feather 328P. There are two tactile switches mounted to the front of the Feather, and in something of a departure from these sort of builds, there are two more on the shoulders of the 3D printed case. Everything is held together with nothing more exotic than a scrap of perfboard, making it easy for anyone who might want to build their own version.

If you prefer your Arduino and OLED gaming to come in a slightly more familiar form factor, the build that was done inside of a Dreamcast Visual Memory Unit (VMU) has always been a favorite around these parts.