Time Machine Mk. 8

An attempt at a DIY watch focused on low-power, high performance operation

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A DIY watch designed for low power, high performance, and style. Inspired by cars, F1, and Neon Genesis Evangelion.

My Instagram page, Github, and personal webpage are all linked below the photos!

2. DIMENSIONS: 41.91mm x 41.91mm x 8.6mm
3. I/O: 4 momentary switches, central rotary knob, twin LCD displays, 5 auxiliary front LEDs, twin RGB backlights, twin floodlights, piezo buzzer, USB port
4. COLORWAY: Electroless nickel-immersion gold on red soldermask, “Thunder and Lightning”
5. POWER: LIR2032 40mAh Lithium Polymer coin cell battery w/ charging over micro-USB
6. SENSORS: BME680 Temperature/Humidity/Barometer/Altitude sensor, LIS3DH 3-axis accelerometer, MAX17048 battery fuel gauge
7. FIRMWARE: written in C/C++ with PlatformIO’s Arduino Atmel-SAM framework


  1. F1 inspired design: Twin 7-segment LCDs on top with a rotary knob in the center, flanked by buttons on either side. Look up "2010 F1 steering wheel" to see what I mean.
  2. Accurate timekeeping: Timekeeping is pretty accurate, it drifts around a bit but never for more than I second I think. Chronograph is also pretty accurate. Millisecond precision.
  3. Various sensors: It has a 3-axis accelerometer and an environmental sensor package(temperature, humidity, pressure, altitude) but I can't get them to work for some reason. Also has a battery fuel gauge IC
  4. Retro design: Besides F1, the watch was also inspired by vintage cars, Kaneda's bike from Akira, and Unit-02 from Neon Genesis Evangelion. The watch has "fender flares" on all four corners, inspired by cars like the Fiat 131 Abarth, Lancia Stratos, and Lamborghini Countach 5000 Quattrovalvole. The LEDs are green to mimic the green "motor-coils" from Kaneda's bike, and the similar colorway of Unit 02 from NGE.
  5. Neat PCB artwork: Of course, design is subjective, and I figure some people won't agree, but I really, really like how the watch turned out. I spent way more time than I should getting the design flashy, but not overly busy, and I think I got it right.
  6. Personal story: I made this during my required service for the South Korean military, one of the hardest times of my life, and it means so much to me. While TM8 is by no means impressive from a technical/skills point of view, I wish it showed others just how strong my passion is for engineering and design. I absolutely love what I do and TM8 is the physical manifestation of that love and passion for my work and what I study.

^ Kanye West inspired ad I made (I'm a big fan of his music)

^ another fake ad I made inspired by an old Japanese brochure for the R34 Nissan Skyline GT-R (I really like cars)

Ok now let's get serious!


Overall design: Chief Design Engineer Eric Min

        The Time Machine Mk. 8 is a huge step forward in terms of technological prowess and design goals. While previous generation Time Machines were very simple watches cobbled together without much thought, TM8 is our first product made with focus on a singular goal: maximum performance and style at the lowest possible power consumption. We wanted to retain the iconic design language of our previous Time Machines, while still incorporating the numerous new features of our new model. This proved much harder than we initially thought, but at the end, it couldn’t have turned out any better.

        Ever since the Mk. 2, the Time Machines’ muscular and angular lines have been an integral part of its design language. With the Mk. 8, we reprofiled the “fender flares” to be better proportioned with the rest of the chassis, as well as mimic the look of the muscular bulged fenders of classic 80’s cars, such as the Fiat 131 Abarth or the Lamborghini Countach. More importantly, while the fender flares were simply a design element in previous time machines, it actually serves a functional purpose in the Mk. 8 since it provides valuable PCB area for the numerous new functions we added to the watch. Without them, we wouldn’t have been able to cram in all the features we had planned.

Ergonomics & Front Fascia design: Systems Designer Eric Min

        The front fascia is a radical departure from the usual two-digit, three-button layout familiar in previous generations. Our team decided two digits was not going to be enough for TM8, since with its new telemetry sensors, the watch would have to relay more information than just time. It took a painfully long time to look for and decide on the right display. Near the end, our team narrowed it down to two options: a 48x64 OLED display, or a 4-digit 7 segment display. We eventually decided on the latter as it fit better with our retro-futuristic...

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  • Finally got sleep modes working on TM8

    Eric Min07/03/2023 at 05:08 0 comments

    Finally I have sleep modes working on Time Machine Mk. 8. I don't have a current measurement device, so I don't have an exact way of measuring power consumption so I could only conduct very simple, short tests. But here are the results:

    1) Display off, press a button to display the time for 2 seconds. Watch is in deep sleep mode when display is off. Running at full 48MHz when displaying time or any other function

    -> estimated battery life of around 50 hours, give or take 10. About 12 readings per hour (once every five minutes). Adjusted time once and didn't use any other function.

    -> about 600uA current consumption I think?

    2) Always on display. Watch is in deep sleep for 990 milliseconds, only wakes up to refresh the display with new info and immediately goes back to sleep. display refresh and other features use full 48MHz.

    -> estimated battery life of around 17.5 hours, give or take 5. Similar use to above, didn't use a lot of the watch's features.

    -> around 2.5 mA of current consumption?

    obviously, the current consumption even with deep sleep enabled is very high. My target is about a week of battery life, which I think is definitely possible. However, I'm still really happy that TM8 can now last almost a full day of use even with an always-on display!

  • BME680 sensor and piezo buzzer now working!

    Eric Min06/27/2023 at 02:44 0 comments

    I got the BME680 environmental sensor working as well. It was relatively painless, I used Bosch's BME68X Arduino library. The Library supports SERCOM Wire objects, so it made life a lot easier.

    I also got the buzzer to work. It's not as loud as I want but it's not quiet either. Weirdly enough it gets pretty hot with just a little use so I'll be using it for very short sound effects, like button presses or warning beeps.

    Now, Time Machine Mk. 8 can monitor acceleration, orientation, temperature, humidity, pressure, altitude, and gas measurement. I don't think I'll be using the last one often, if at all, but the other ones should give me a healthy amount of telemetry to play with!

    I'm slowly but steadily working my way through getting everything working on TM8. Since I now have all major sensors and I/O working, I now need to focus on rewriting code for the chronograph and tachymeter, as well as trying to get the SPI Flash chip working.

  • Finally got the accelerometer working on Time Machine Mk. 8!

    Eric Min06/17/2023 at 07:31 0 comments

    After weeks of misery and head scratching, I finally got the accelerometer working for TM8. Huuuuuuuuge load off my shoulders.

    There was a very small hardware quirk on the SAMD21G18 chip that was messing around with my SERCOM implementation. I set SERCOM2 on Time Machine Mk. 8 by calling

      pinPeripheral(4, PIO_SERCOM_ALT); // SDA: D4 / PA08
      pinPeripheral(3, PIO_SERCOM_ALT); // SCL: D3 / PA09

     , which worked fine for the LCD, but not for the LIS3DH accelerometer and BME680 temp sensor. After muck dicking around and googling, I found this GitHub issue, which led me to replace PIO_SERCOM_ALT with PIO_SERCOM, and voila, the accelerometer now works perfectly. So now my SERCOM setup code looks like this:

    #include <Wire.h>
    #include "wiring_private.h" // pinPeripheral() function
    TwoWire wire1(&sercom2, 4, 3); // new Wire object to set up second I2C port on SERCOM 2
    void setup() {
      pinPeripheral(4, PIO_SERCOM); // SDA: D4 / PA08
      pinPeripheral(3, PIO_SERCOM); // SCL: D3 / PA09

    This is incredibly exciting because TM8's accelerometer has many exciting potential applications, such as free-fall detection, tap detection, or even cornering grip analysis for track driving! I don't have the BME680 working yet but it should be cakewalk. Coupled with the BME680's altitude sensing, Time Machine Mk. 8 can even be a skydive computer!

    I'll keep the project updates rolling

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Dan Julio wrote 06/11/2023 at 22:58 point

Nice job!  Always nice to see people mix aesthetics with design.  Those little I2C LCD modules are cool.  Can you share their PN and where you got them?

  Are you sure? yes | no

Eric Min wrote 06/12/2023 at 16:39 point

they’re from and are not available anywhere else. Pretty expensive at 12 bucks a pop

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Dan Julio wrote 06/13/2023 at 04:14 point

Thank you!

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Sam wrote 06/11/2023 at 22:29 point

This looks super cool. How accurate is the environmental temperature sensing? I thought your body heat would interfere with the reading.

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Eric Min wrote 06/12/2023 at 16:40 point

I haven’t gotten the sensors to work with the watch yet… it’s a problem I’ve been stuck with for weeks

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quanghaidmn739 wrote 06/08/2023 at 09:10 point

That's a very good and beautiful watch.

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Eric Min wrote 06/09/2023 at 04:19 point

thank you! I think so too :)

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davedarko wrote 06/08/2023 at 08:50 point

that's a cute watch :)

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Eric Min wrote 06/09/2023 at 04:20 point

thanks man! Big fan of your game&watch style LED space invaders game btw

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