Great Scott!

…and here it is, the finished article.  Apologies for the rough look of the housing; it has been to camp and back, as well as needing running repairs in the field (literally) when a wire pushed through and broke a track. Head torch, pen knife and ingenuity came to the rescue.

NB: For the purposes of this video I shortened the rate at which the Destination and Last Departed times cycle.

No time like the present
One thing I haven’t mentioned is how it kept time. I ran my Pi with a wifi adapter; this meant I could have it connected to my phone, which had its WiFi hotspot enabled. Not only did it mean the program had the correct time, but I could also SSH into the Pi to shut it down. An alternative would be to use an RTC (real time clock) add-on and modify the code to get the current time from there.

Running on startup
There are numerous examples around but to save you a couple of minutes; run the following command

sudo nano /etc/rc.local

Then enter the following as the last line

python <path to the code>/Back2TheFuture.py &

The & is very important as this tells the operating system to run the command then carry on processing, rather than wait for the command to finish. If you’ve never used nano press CTRL-X to exit then follow the prompts to save the file. Next time you reboot the python script will run automatically

Reactions
“You Geek” or “You Nerd” then followed by “but that is cool” were well received.  What’s more worrying is the state of teenagers awareness of classic 80s movies.  The number of Explorer Scouts that asked “What’s that?” or “Are you Einstein?” was mildly worrying.  They were all told to hunt out the films when they got home and watch them to aid their education 🙂 I was asked by one lad “Did you buy that off EBay?”

The real heart warming thing was the number of youngsters (and a few adults) that either correctly guessed there was a Pi inside or knew what it was when I told them. There’s hope for them yet….

Shopping list
Here’s a shopping list of the key components to this project. I have provided links to where I got the part from (and in some cases found alternatives as well)

  • 3x Adafruit 16×8 LED Matrix Driver Backpack – HT16K33 [SKPang] [PhenOptix]
  • 3x 4 digit 7 segment display Green [SKPang]
  • 3x 4 digit 7 segment display Red [SKPang]
  • 3x 4 digit 7 segment display Yellow [SKPang]
  • 15x 5mm Yellow LEDs [CPC]
  • Stripboard [CPC]
  • Mini breadboards [search “breadboard mini” at CPC] [Pimoroni]

Plus the usuals; wire, solder etc.  My shopping list was slightly longer as my soldering iron got a little too close to our plastic kettle and nearly made it all the way through before I smelt the burning – oops!

Enhancements

  • Add AM/PM LEDs – I ran out of time and physical space. This would provide further accuracy to the film prop
  • Audio – play the theme tune
  • Input – button presses to change times or perform other functions
  • Numeric Keypad – add further film authenticity and enter your own times
  • Web interface – If you’re WiFi connected to your phone/tablet all sorts of interactions could be created
  • Bigger/better flux capacitor – more LEDs, variable chase speeds, use LED strips

Summary…

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