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Back To The Future Time Circuit Clock

Back To The Future Time Circuit Clock with clock, alarm and FM radio receiver.

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This project was created on 04/06/2014 and last updated 9 months ago.

Who wouldn't want a Time Circuit Clock after watching Back To The Future as a child? I wanted one and now because of the Sci-Fi contest there is no more excuse not to build one.

Other than the cool looks and envy of others, the build will have 3 usefull features:
- Clock
- Alarm
- FM radio

The team:
- Me, atheros, project leader. I'll be doing most of the stuff: planning, soldering, gathering components, programming...
- bwa - my brother in law. He is helping me make the PCB boards, the casing for the clock, debug software and hardware. Additionally he is providing some more advanced tools and equipment needed for the job.


You can find all the sourcecode and schematics here:

This projects attempts to recreate a Time Circuit Clock from Back to The Future movie with some additional features (and one feature missing, obviously).

Some interesting facts about this project:

  • 22-23 hand made PCBs
  • > 160 resistors
  • 396 LED displays pins to connect
  • 24 shift registers
  • original Time Circuit didn't use real displays for months, now I can understand why :)

No matter the difficulties, IT WORKS!!!

  • 23 × 74hc595 shift register This is used to drive the displays
  • 2 × PDA54-11SURKWA 14-segment LED display - RED
  • 2 × PDA54-11CGKWA 14-segment LED display - GREEN
  • 6 × PDA54-11SYKWA 14-segment LED display - YELLOW
  • 5 × DA56-11SURKWA 7-segment LED display - RED
  • 5 × DA56-11CGKWA 7-segment LED display - GREEN
  • 2 × DA56-11SYKWA 7-segment LED display - YELLOW
  • 2 × Arduino Pro Mini - compatible It must have A4, A5, A6 and A7 pins!
  • 1 × Si740x Breakout Module from Sparkfun I2C radio module
  • 1 × Level shifter (5V<>3.3V) from Sparkfun

See all components

Project logs
  • Status

    9 months ago • 2 comments

    So time is up!

    Here is the presentation video:

    Currently working features:

    • FM radio receiver
    • FM frequency adjusting and editing
    • setting volume
    • RTC time display
    • RTC time setting
    • 24 7-segment characters and 20 14-segment displays

    What didn't make it to the build in time:

    • alarm
    • RDS
    • casing
    • a few more buttons

    RDS was really problematic. As explained in the video, I didn't manage to receive any kind of information from Si4703 Arduino library from Sparkfun. It seems it has a very limited support and unfortunatly blocking function calls (like lose keypad responsivness for 15 seconds awaiting for RDS data). I hope I'll be able to add this feature later.

    Alarm and more buttons was simply a matter of time, which we run out of. Nothing difficult there, just some additional work. As for the casing, it other than little time we had, we thought it's safer to make the casing (or in this case front panels) out of wood, as it is easyer to work with. We had silver paint to pain it, but we run into lots of hardware bugs while testing all hardware connected together (first time 10 hours before this video recording). A good example is the LED connected to pin 13 of Arduino that prevented the Keypad library to work properly with the pins for the keypad we chose - so we removed it :)

    There is ofcourse a lot more we would have wanted to do, but I guess we will need to leave it for later.

    The contest was a lot of fun and I hope there will be more!

  • Quick Update

    9 months ago • 1 comment

    What's new?

    We did a lot with bwa since last update. I'm spending a lot of time working on the hardware. I decided to post some pictures.

    Those are 7-segment displays for first two rows of the time circuit with the display controller board. Notice the ugly prototype boards driving the displays. It turns out those are very hard to make compared to etching normal PCBs and adding just a few jumper wires. After I made those, I decided it's time to end this prototype madness.

    The time was running low, so it was time to speedup and make more PCBs at once. You can see on this photo 2 14-segments display boards and 3 drivers for them.

    Routing lots of parallel signals on a single-sided PCB is a nightmare. We tried making double-sided PCBs, but vias and board alignment were very difficult, so all our boards are single-sided. In some eagle files, you'll see wires on top side, in the PCBs we made, they are replaced by normal wires.

    Here you can see most of the PCBs we made, most assembled.


    Because of time constraints, lack of tools and experience, we've decided to go with a wooden casing. This is a partially cut front panel for one of the rows.

    And finally:

    This is how it looks. Not too bad!

    The radio

    I am very disappointed by the Si470x module. We failed to read any RDS from it, might be caused bad reception (I had to pull out a long write from the basement where bwa's workshop is). The main problem is when it is powering up. 9/10 it causes a loud click in the speakers and it reboots the arduino. It looks like power loss of some kind. Large power supplies and capacitors don't help. The strange thing is that it works flawlessly when there is additional power connections from my notebook. I'll have to look into it later.

    Other than that, the libraries for arduino don't offer much: seek up / down, set frequency, set volume and read RDS - blocking... I have no idea how to address this issue.

    What's next

    So I have most of the hardware, some untested and a beginning of the casing. I think it's time to code the Time Circuit Board:

    There are chances it might work :)

  • FM radio delivery

    9 months ago • 0 comments

    Delivery issues

    It turns out Polish Post Office is the worse courier company in Poland, and probably don't have lots of competitors in Europe. The package containing my LEDs and some other highly optional components for this project was supposed to arrive within 48 hours. The final time was 182 hours. The second package, the one holding 3 kinds of FM radio modules was still late.

    The courier called me 7 days after the package was sent. Unfortunately I wasn't home. I figured it's not a big problem, I'll get it from the post office the next day. And this is where it is getting really wrong. It turns out the courier didn't leave the package at the post office as he was suppose to, instead he drove the package back to the warehouse where it will probably wait a few more days before being sent to me one more time. Needless to say chances for it reaching me before the end of the contest are unbelievably slim.

    I was ready to give up, but then I decided to go through online catalogs of all electronics shops in Warsaw and it's surrounding - and I found what I was looking for! SparkFun's Si4703 FM Tuner Basic Breakout. I bought it of course so I can continue working on this project.

    I learned two things:

    • never trust Polish Post Office
    • using rare components when you have a fixed deadline is risky at best

    Now I'm wondering, what will I do with the extra 3 or 4 FM radio modules if they ever arrive...

View all 8 project logs

Build instructions
  • 1

    Get ALL the components you need. It might sound simple, but I went through lots of trouble to get it.

  • 2

    Install Eagle CAD (free version)

  • 3

    Clone repository

    You'll find sourcecode, schematics and board designs there.

See all instructions


Mike Szczys wrote 9 months ago null point
Thank you for so thoroughly documenting your build. All the different stages from concept, to breadboard, to etching and assembling were really a treat to read through. Great job all around!

Are you sure? [yes] / [no]

atheros wrote 9 months ago null point
Thank you, I'm happy you liked it.

Are you sure? [yes] / [no]

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