While you can build any number of bare-metal applications for Sensor Watch, when we refer to the Sensor Watch firmware, we’re really talking about Movement, the community firmware for Sensor Watch. You can read more about Movement here; for now, the important thing to know is that it manages a series of watch faces that you advance through using the mode button. It’s a very similar idiom to the classic Casio F-91W, which advances from Clock -> Alarm -> Stopwatch -> Time Set, and then wraps around to Clock.
Movement offers many more watch faces — some of which, like World Clock, you can include more than once! Still: you’d be pressing the Mode button for hours if we included them all, so instead, we only build a subset of the available faces into any given firmware. This means that you can download an alternate firmware that includes the kind of functionality you want, or build custom firmware that includes just the watch faces you desire.
1 - Flashing Firmware onto Sensor Watch
The small spade at the top of Sensor Watch is designed to plug directly into a USB Micro B cable. This allows you to flash new firmware directly onto the device via the built-in UF2 bootloader.
To accomplish this, disassemble your watch completely, and plug the Sensor Watch board into a USB Micro B cable plugged into your computer. Double tap the tiny Reset button on the back of the board; the LED should begin to pulse red (or blue, for Special Edition boards). You should see a disk drive called “WATCHBOOT” appear on your computer.
Drag a UF2 file with the firmware you want to use onto the WATCHBOOT drive. You can find some prebuilt firmware images right here on the Sensor Watch website, or you can build your own firmware with just the watch faces you want to wear.
After you drag the file over to WATCHBOOT, the LED should pulse intensely for a few seconds, and then turn off. This signals that the firmware has uploaded successfully; you can now reassemble the watch and wear the new firmware on your wrist.
NOTE: As a failsafe (in case the watch inadvertently enters bootloader mode while being worn), the bootloader is programmed to exit after 60 seconds of inactivity. This means that once you enter bootloader mode (red LED pulsing), you have one minute to copy over your firmware, or the watch will exit bootloader mode, and you will have to double-tap reset again.
2 - Prebuilt Alternative Firmware for Sensor Watch
This section contains the stock firmware for Sensor Watch, as well as several prebuilt firmware images featuring an alternative set of watch faces. To flash one of these firmware images to your Sensor Watch, follow the instructions here.
Prebuilt Firmwares
Note that each firmware comes in three flavors, depending on the color of your circuit board:
There are a few Special Edition boards with a red/blue LED that are blue in color. For these boards, you should download the blue firmware.
The classic Sensor Watch circuit board was green. If you have this board, you should download the green firmware.
The new Sensor Watch Lite circuit board is red. For these boards, download the red firmware.
If you put the wrong color of firmware on a board — specifically, if you put the blue/green firmware onto a red board or vice versa — the LED will light up bright yellow to indicate that there was a mismatch. Make sure to match the color of firmware to the color of your board!
Also note that all of these have the “Preferences” and “Time Set” screens at the end; for brevity they aren’t included in this listing, but you will always have access to them.
Movement: Backer Edition (with temperature display)
Required Sensor Board: Temperature Sensor
The first Sensor Watch boards that shipped were with orders that automatically included a temperature sensor board. As such, the set of watch faces that shipped with those boards included a temperature display.
Post-campaign, the temperature sensor board was optional, so we replaced the temperature display with a stopwatch. If you bought a temperature sensor board and wish to have a temperature display, use this firmware; it’s identical to the standard firmware, but replaces the stopwatch with a temperature display.
Simple Clock - A basic clock with date for timekeeping.
World Clock - You can configure this with a custom two-letter title and any time zone.
Sunrise/Sunset - Local sunrise and sunset times.
Moon Phase - Tonight’s moon phase. (press Alarm to see days in the future)
Temperature - As measured from the temperature sensor board. (Alarm toggles C or F)