The Singularitron is something of an oddity, to put it lightly. It is simultaneously the worst smartwatch I have ever seen, and also an interesting, highly novel piece of hardware with a certain je ne se quois that has me pining to get my hands on one. Unfortunately, you cannot just pick up a Singularitron at your favorite retailer… well, possibly if your favorite retailer is Sanford and Son Salvage, but aside from that, you have to build your own. Comfortable with that? Well, you still probably cannot make one, because the display has not been manufactured for many years. Impractical? Yes, absolutely, but that is just what developer Zack Freedman was shooting for with this wonderful, awful smartwatch that was designed primarily to be an eye-catching piece for conferences.
The Singularitron’s wrist strap was taken from a wearable barcode reader. The detachable base of the device is a massive 3D-printed enclosure with a scroll wheel, five buttons illuminated by NeoPixels, and four cartridge slots for expandable functions. A removable AA size rechargeable battery powers the Singularitron somewhere between 25 minutes and 12 hours, according to Freedman.
PCBs (📷: Zack Freedman)
A Teensy 3.2 built into the circuit board serves as the primary processing unit. An attached daughterboard adds an accelerometer, gyroscope, compass, and a Bluetooth Low Energy radio. The display is a four-line, 20-character vacuum fluorescent display (VFD), which is ultra-bright, even in the daylight, and which Freedman describes as a terrible choice for a wearable. And he has a point — the VFD requires 36 volts and is highly breakable with a casing made of glass. One bright point for the VFD is that it draws a relatively modest (for a display) 180 milliamps. A vibrating motor and USB-C interface round out the features of the base device.
The home screen is a dashboard showing current time, battery life, a compass, and measurements from any attached sensors. All of these components left no room for a backup battery, however, so each time the battery is replaced, the current time will need to be reset.
Expansion cartridges (📷: Zack Freedman)
The expansion cartridges are identified by a unique ID stored in an onboard EPROM. When plugged into the Singularitron, one of the buttons lights up to access its functionality. If the cartridge contains sensors, that data will also appear on the home screen. Each cartridge has 12 contacts to connect with spring loaded brushes on the main device. These contacts interface with the main I2C and SPI buses, as well as analog and digital GPIOs.
Staying true to the mission of being impractical, the Hyper Flashlight cartridge offers a blinding 200 lumen LED that draws a full ampere of current and overheats within three minutes. The environmental module contains a barometer, thermometer, and VOC sensor. Another cartridge has a no-contact infrared thermometer and a laser pointer for targeting. It is not of much use, however, because the thermometer has too wide of a viewing angle and mostly records its own temperature.
Not content with this initial batch of modules, Freedman also created the Photon Wrangler that can sense color, brightness, proximity, and gestures. The Thunderhand cartridge provides a magnetic field sensor, and the Breathalyzer module detects ethanol for amusement at house parties. If you find yourself needing more processing power, there is a cartridge with a Teensy 4.0, which is twelve times faster than the main processor. To demonstrate its power, Freedman blinked an LED.
Freedman has big plans for the future of the Singularitron. He is planning to add a Geiger counter, a multimeter, and — drumroll please — a taser. Just a suggestion, Freedman, but it may be wise to require a reading from the breathalyzer before activating that taser.