This next watch pretty much perfectly matches what you would expect to see when hearing the phrase “binary watch”.

Binary watches can come in more complicated sequences if you desire something a little more in-depth. Some binary watches have a third row to represent the seconds. If both are lit you are over the final quarter and most likely within the last 10 minutes of the hour. 11[…] = '48-59' minsIf only the left one is lit you are over half way through the hour but probably not into the last quarter (or only just!). 10[…] = '32-47' mins Because this is at times an ultra low voltage application of the Atmega328P it needs a special kind of bootloader. As discussed in step 3 on selecting the microprocessor with the right frequency, this circuit will run at a frequency of 1MHz. This was to make sure the processor still works reliably at the lowest possible voltages of 2V. Have you ever heard of binary watches? Images reminiscent of sci-fi films may come to mind upon hearing that term. Or perhaps instead you may think they are watches designed specifically for computer geeks. The latter may be closer to the truth. These types of watches do represent a more obscure, niche market within the watch industry. It both looks exceptionally stylish and works great with a simple user interface and battery life up to two years. Arriving at the final design was an iterative process where a lot of different problems had to be solved. In my opinion the end product turned out great and is something I love to wear on a daily basis. To upload the code first open the sketch I've attached here. Connect an USB FTDI adapter to the serial programming points. Once again, these connections can either be pressed onto the PCB or connected by soldering the pins or female headers that has to be desoldered later. I used female headers.

Although not having worn the watch in the presence of normal humans, I can already guarantee that now everyone will be able to easily identify me as a nerd.

What Is A Binary Watch?

Electrical: Redesigned the PCB from scratch, adding temperature sensing (from the internal Atmega temperature sensor) and battery voltage readings (from a voltage divider that gets referenced from the Atmega's internal bandgap voltage). So now, in addition to the time and date, the watch displays the temperature in Celsius and the remaining battery voltage on a scale from 1-10. I added status LEDs to communicate which value is being read (Time/Date/Temp/Batt), which required adding another column of LEDs to the multiplexing matrix. I also moved most of the passives to the top layer as I prefer the 'busy circuit' aesthetic over the much cleaner look that you've implemented. The bottom button is always responsible for the brightness and color adjustments, independent of what mode you are in. When the user enters "Choose Color" mode, the LEDs start cycling through all of the possible RGB colors. The user can pause the animation and choose the color that they prefer for that specific mode (Display Time in red, Display Date in blue, etc.). The colors are meant to be easily customizable by the user to help them distinguish between the different modes.