Custom BTTF Time Circuits

[Shep]

As part of my engagement, I decided to come up with a BTTF-themed wedding invitation. Originally I wanted to go for a BTTF Time circuit replica, where each of the three dates would be marked by labels. When I made the design for the postcards however, the proportions were way off, so I opted to add another line to it. It would be hard-coded with three preset dates in it, all powered by one single Arduino. Here's what the final result would look like, from the front:



Which is what the front of the invitation postcard looks like. Once I had these ordered, I ran into a problem: no one made white alphanumeric displays. So I searched on Google, then on eBay, and found one guy that was selling them. I was cautious, but I ordered from him. The good news? The board was pre-assembled, and came in all the right colors I needed. The bad news? Well, they only came in 4-digit varieties. Or so I thought. Turns out, they're very open to custom orders, so I'm in the process of getting one of those squared away to provide 3 digit varieties (for the month) and two digit varieties (for the day, hour, and minute). Smooth sailing so far!

I got the displays in a few days ago, and finally got around to hooking up today. First, a shot of how it looks connected to the Arduino:



Forgive the mess behind it as I am in the process of moving my fiancee in and haven't figured out where my "electronics corner" is yet

On the left, you can see a breadboard with a DC jack and wires (to provide the power for the digits themselves), followed by the digits in the middle (1" tall), and on the right, the Arduino microcontroller, the brains behind this operation.

So in order to mimic the top line, I got four displays exactly the same. Here's a few shots that show one display with the four setups going through it:








These suckers are bright! Next step: seeing if I can rig up a circuit to allow multiple displays to be used at once via a decade counter. There's 19 displays and only 13 pins, so needless to say, I'll be needing one or two of the decade counters.

[Shep]

It's been a while since I posted an update on this, but I do have more progress in this build, so I thought I'd share.

First, a few notes: the DC Boarduino I was using is long gone in favor of a Pro Trinket (which is a much smaller package and has a built-in voltage regulator), and my soldering skills have improved vastly over this timeframe. While also busy with other projects, I'm coming back to this one and honing in on it as my (also open-source) Roomba project is 98% done. I say "98%" because I need to source a voltage regulator for when it's charging to bring the voltage down a bit, but beyond that it works flawlessly.

ANYways, in addition to swapping out the Arduino, I had major self-inflicted problems with the displays. Apparently the two sets of pins are not designed to be two inputs etc, but rather to allow them to be daisy-chained! I didn't realize this until the supplier pointed this out, so that solves the whole "19 pins on a 13-pin Arduino" problem and allows me to utilize one Pro Trinket for it, saving me a TON of time and headaches. This initial confusion caused many strange happenings and I couldn't figure out what in the blue tarnation it was doing, but now that I've been made aware of it, I can correct the issue, swap out any displays I may have burned up in the process, and we'll be good to go!

Swanky!

Also, the 2-digit and 3-digit displays arrived this week, so I took the opportunity to put the yellow ones together. After some initial trouble with an under-capable power supply (9V 1A isn't enough for one row), I upgraded the power supply (Now running a 12V 6A laptop supply), and it works like a charm!

I'm probably going to open-source the code for this once I get it tidied up, but right now I have it reading serial input, and have also plugged in the displays backwards in terms of logic (i.e. once any given display "overflows", it moves the overflowed digit to the display on its right instead of its left), but that's a very straightforward fix.

Enough talking, here's a picture of the current result!



Interestingly, the difference in brightness between the 4-digit yellow and the 2-digit/3-digit yellows is just as apparent in person as it is in this picture. I may have a loose connection somewhere, not sure, but the excellent news is that I can now start designing the aluminum enclosure for the time circuits to reside in now that I can get exact measurements!

Many, many thanks to Embedded Adventures for both designing the products you see above, and for all the help and support they have provided thus far. I'm telling you, these guys are phenomenal, and while they may not have as wide of a selection or marketbase as Adafruit, they make up for it in the "quality over quantity" department. Not that Adafruit has bad support (their support is actually fairly good), but now I am a loyal customer to both. Especially since they took the liberty of doing all the design work themselves for the 2-digit and 3-digit circuits instead of just handing it in my lap and saying "you do it". They ran it by me, I okayed the designs, and now they're here and brighter than ever! I for one cannot wait for this project to come to completion, and am diligently working on seeing that it stays as far ahead of schedule as it currently is.

More updates to come!

[ALEXAKOS]

ha!
Fantastic! And the best way to keep your mind off the wedding.
Congrats buddy... ON BOTH!

[Shep]

ha!
Fantastic! And the best way to keep your mind off the wedding.
Congrats buddy... ON BOTH!

Thank you!

Just another update: managed to solder together some more digits, until I realized testing would be quite annoying until I get the physical unit built. So relying on my high school CAD experience, I drew the physical unit up in LibreCAD, with every dimension you'll ever need to replicate it:



Everything's in millimeters, but keep in mind this relies on a custom design for the 3-digit and 2-digit varieties. Front view on the bottom-left, side view on the bottom-right, and top view on the top-right. Unfortunately, it looks like I may need a couple more of the 3-digit boards, mated to white LED units. While this (hopefully) will eliminate the need to get replacement 4-digit white displays, it is wholly necessary as I totally did the math wrong and wound up with much less side margin on the top row than I thought I had. My thought was that I could simply remove (or cover up) two of the digits and be fine, but I don't have the width to do this and make it look decent.

I'm actually thinking of having the phrase "PLEASE SIGN IN" displayed on the top row instead of "YOU'RE INVITED" when it comes to the physical unit, since this will be the guest book (hence the slot at the top). I guess my only question to the fabricators out there is this:

Anyone know a good source for converting this into an aluminum or stainless steel reality???

EDIT:
Oh yeah, and my fiancee noticed the year was wrong on the picture of the yellow digits above. Simple code change, but I totally didn't even catch that until she said something. Should be 2015 instead of 2014. [insert BTTF joke here ]