Unitron

Unitron

Unitron is a kitchen tool for working with important cooking units -- time, space, and mass -- using tactually-pleasing switches, knobs, and buttons, non-intrusive beeps, and exciting lights.

Unitron allows you to convert between common volume units (cups, ounces, tablespoons, teaspoons and milliliters). It can also convert from volume to mass (and vice-versa), taking into account the density of common cooking ingredients. This makes measuring ingredients for volume-based recipes with a kitchen scale a breeze. It also functions as a handy countdown timer!

Watch the demo video here.

Unitron was developed by Andy Lustig.

Build Guide

BOM

Additional Components

• A rechargeable 3.7V lithium polymer (LiPo) battery
• Threaded mounting magnets
• A satisfyingly knurled metal knob.
• Keycaps from WASD keycaps:
  • number pad keycap set for the numbers (black, large font)
  • The number pad set comes with a 1x2 "0" keycap, but we want a custom 1x1 "0" keycap (R1 1x1, 26 font, center-center alignment)
  • R1 1x1 keycaps (sky blue, green, and orange)
• Relegendable keycaps are a good less expensive alternative.

User Guide

[blocked]Component Diagram

[blocked]Turning it on!

The first step to using your Unitron is to turn it on with the smaller, right-most On/Off switch. When Unitron is on, the LED panel and the red Power indicator light will be lit up. Turn it off to save power.

Switching Modes

Unitron has a countdown timer mode and converter mode. To switch to modes, click the blue Mode button. Unitron will startup in the start_mode specified in your settings.py file (see Modifying Unitron functionality). If the blue Mode button is pressed down when turning on Unitron, it will startup in the opposite mode.

[blocked]Countdown timer mode

To set the timer, use the number keys. To specify minutes and seconds, you can use the decimal key, e.g. 20.30 corresponds to 20 minutes and 30 seconds, while 20 corresponds to 20 seconds.

To start the timer, flip the Toggle switch. To pause the timer, flip the Toggle switch again. The top, red row of the LED panel shows the time remaining, and the bottom orange row shows the original time requested.

To clear the timer, pause the timer (if necessary), then push the green Clear button.

As the timer counts down to 0, a bar of Timer lights will progressively light up. When the timer reaches 0, it will beep three times.

[blocked]Converter mode

Unitron converts from blinking to solid units in the Unit light row.

You can enter the amount of the blinking "from" units with the number keys. This will be shown in the LED panel. The corresponding amount in the solid "to" units will be shown in the other row of the LED panel.

You can change units using the Knob. Turning the knob changes the blinking "from" units. Turning the knob while holding it down changes the solid "to" units.

You can swap the "from" and "to" units with the Toggle switch. If you find it difficult to hold down the Knob while turning it, you can use the Toggle switch to swap, turn the knob, then flip the Toggle switch back.

Conversions between volume and mass require knowing the density of the ingredient. You can specify cooking ingredients by holding down the orange Ingredient button while turning the Knob. Note that the ingredient button only functions when the two units selected are mass and volume -- ingredient type does not matter when converting from mass to mass or volume to volume.

Charging

Unitron is rechargeable. To charge it, plug a USB C cable into the USB port at the top. The yellow charging indicator will be on while charging and will turn off when the battery is full.

Placement

The back of Unitron has four strong magnets. It is meant to be placed on a metallic refrigerator.

[blocked] Modifying Unitron functionality

Unitron uses CircuitPython. You can modify the code it is running by connecting it to your computer via the USB C port and mounting it as a disk drive. Basic settings can be adjusted by editing the settings.py file.

Change the mode that Unitron starts up in when turned on by editing start_mode.

Adjust the number of beeps for when the timer expires by editing beep_num.

To add new ingredients to Unitron, modify ingredients. Specify the density in grams per teaspoon. You can try to measure these densities yourself, or you can trust the internet. Here's one site with information.

Make sure to eject Unitron before disconnecting.

Updating

CircuitPython

Connect Unitron to a computer via the USB C port. To enter bootloader mode, hold down the BOOT button, and while continuing to hold it, press and release the RST button. Continue to hold the boot select button until the bootloader drive appears on your computer as RPI-RP2. Download adafruit-circuitpython-adafruit_qtpy_rp2040-en_US-9.0.4.uf2 file from the release page and drag it onto the bootloader drive. The RPI-RP2 drive will disappear, and a new drive called CIRCUITPY will appear.

If you have trouble, take a look at the official CirtcuitPython installation instructions here.

Unitron Software

Connect Unitron to a computer via the USB C port. It should appear as CIRCUITPY. Download the latest software release. Unzip the download and copy the files onto the CIRCUITPY drive.

License

CERN Open Hardware Licence Version 2 - Permissive