The microprocessor had to meet certain criteria. It needed at least nine pins for GPIO, eight for the LEDs and one for the push button. It also needed an I2C bus where it could act as a master to poll the RTC for the time. At lastly it had to be able to operate on low voltages and not draw exorbitant amounts of current while powered. The Atmega328P-AU nails all of these criteria while still being small enough to not eat the whole PCB area. A big plus is that it's also used for most popular Arduino boards. This means it has a lot of support and it should be familiar to work with as I'm experienced with Arduinos. Another way to think of that is that you just invert the numbers from the right-most 1 to decrease the number by ‘1’. 101100 = 44 Our recommendations in binary watches represent only a small sample of the options out there. But in our opinion, these are some of the better and more stylish options available. This is kind of a typical layout for binary watches. You see that on the top row, both the 2 and the 1 are lit up. You would add 2+1 to get 3. On the second row, you see that the 16 and the 4 are lit up. Add 16+4 to get 20. So the time here would be 3:20. Pretty simple.

To save on battery life, the LEDs won't light up permanently: Just press one of the two operating buttons, and the LEDs will light up for 6 seconds and with a little practice, this will be plenty of time to read the time! Otherwise, simply push the button again ;) I'm glad you asked. The lowest row on the watch represents the least significant bit and the upper row is the most significant bit. The row from the bottom to the top has the values: 1, 2, 4, 8. So each digit has its value coded upwards and you read the digits from left to right. This principle will be the same for the rest of the functions on the watch. The use of RGB LEDs will help distinguishing between different functions and modes using different colors. The colors are chosen by the user and can easily be adjusted to whatever color palette they prefer. This allows the user to easily navigate through the functions without getting confused.

Numbers that end with 0 are even

I've always been fascinated by both interesting ways of telling the time and binary code. It's amazing the amount of information can be stored in simple ON/OFF signals. I knew I wanted a new wrist watch so why not combine binary code with a wrist watch, and do it as an awesome DIY project? Update 17/03/19: The gerber files in step 6 has now been updated to fix the board outline on some manufacturers gerber interpreters. In this guide I will represent lit LEDs as 1 and unlit LEDs as 0. For the most part I will just list the right-most positions (assume the rest are unlit). Numbers that end with 0 are even If 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 If you look at binary numbers frequently and already know 111000 (I mentioned it above), you can spot that last one in an instant. Final thoughts

I will take you through the process from idea to making your own binary wrist watch you can wear with pride. Yes there may be a small learning curve, which is one caveat to using a binary watch, but it is petty simple once you get the hang of it. And that leads us to the next question….. How Do You Read A Binary Watch? Take a number like 110111. Initially one might work that out with lots of small additions. 1 1 0 1 1 1Even if tech is not your thing, you may just simply like the aesthetics of a binary watch, or just want something a little bit different. After all, its not very often that you see people wearing these things. The rest of the time programming went into making the other modes as intuitive as possible. I figured that having the same button responsible for the same functionality across all modes would be the most intuitive. After some testing, this is the button configuration that I came up with: The primary requirement for the RTC was accuracy. I knew that the watch would not have any internet connectivity and thus would not be able to recalibrate itself via an internet connection, the user would need to recalibrate it manually. Therefore, I wanted to make the timekeeping as accurate as possible. The M41T62 RTC has one of the highest accuracies that I could find (±2ppm which is equivalent to ±5 seconds per month). Combining the high accuracy with the I2C compatibility and the ulta low current consumption made this RTC a good choice for this project. DC-DC Boost Converter