What was your most creative/unexpected communication interface?

The forum is all new and I’m taking a dive at launching a discussion. I found no guidelines against this kind of discussion, so I hope it is no too off topic. If it is, I apologize and you can close/delete this thread.

Anyway, I love the unexpected in my job. Coming up with creative solutions to problems is really what drives me as an engineer, and I love hearing about other people’s stories.

Here, I’d like use to share our most unexpected or creative experience in connecting two devices/network together for communication.

I’ll go first.

About 30 years ago (I am not fully sure of the year, I think it was 92 or 93), I ended up helping a local farmer because “I was good with computers”. Anyhow, this was a potato sorting facility. Trucks come in, get weighted, unload the potatoes, get weighted again and the weight difference is the amount of potato they brought.

The scale, was a huge plate of concrete with a metal band around it and it would weight the entire truck in one go (two for trailers). For some reason this scale and some sort of official status (I think it could be used for public weighting, even if it was on a private property) and it was calibrated quarterly by the federal institute of metrology (here in Switzerland) and the electronic was sealed with an official seal (we called that “plombé” in french).

The weight measure was indicated on what I think was a VFD display (but it was orange) and there was absolutely no digital or analog interface to the measure. The display was inside a little shed and you could not see it from the outside, so you had to get in or have someone inside tell it to you.

I was walking with the farmer to his house to help him with his brand new classic II and I noticed the weight on the ground. I asked what it was and we got to chat, and something leading to another, I was tasked to find a solution to automatically record the weight (at this time I didn’t know the electronic was sealed and calibrated, so I accepted).

After failing at all tries to get something our of that scale, and an absolute wall from the authorities calibrating it, I had an idea. What is I could take pictures of the display and read it? Of course this was way out of my league and I had no idea how to do it, but I got to it.

Long story short (this post is already long), I was able to get my hands on a Dycam throught someone I knew at EPFL. It was an early webcam that could take black and white picture through a serial interface. I placed a mirror above the display, and the camera in front of it, and I could take pictures of the display. I had some help from my older brother which is a physician specialized in optic, because I had no idea how to focus the field properly.

I wrote a small program to do OCR (well, some crude form of it) on the image, and after a few weeks of tuning I was able to get a pretty reliable system. I added an external display outside the shed using a refurbished electro-mechanical display from CFF (the swiss train company). And all measures would be written to a text field with a timestamp.

It was very early in my career, but I think it was my most unexpected creation to have two devices communicate.