[BorisDigital] was mesmerised by a modern elevator. He decided to see how hard it would be to design his own elevator based on Raspberry Pis. He started out with a panel for the elevator and a call panel for the elevator lobby. Of course, he would really need three call panels since he is pretending to have a three-floor building.
It all looks very professional, and he has lots of bells and whistles, including an actual alarm. With the control system perfected, it was time to think about the hydraulics and mechanical parts to make a door and an actual lift.
It is still just a model, but he does have 10A AC switches for the pumps. Everything talks via MQTT over WiFi. There’s also a web-based control dashboard. We didn’t count how many Pi boards are in the whole system, but it is definitely more than three.
If you are wondering why this was built, we are too. But then again, we never really need an excuse to go off on some project, so we can’t throw stones.
Want to see a more practical build? Check it out. Perhaps he’ll start on an escalator next.
One word: SimTower. Or is that two? Or four? Either way, https://en.wikipedia.org/wiki/SimTower.
Haha. One of the first jobs I applied for out of school had “write an elevator control system” for its coding test. They allowed 3 hours for it, and every 20-30 minutes they threw in additional requirements, some in direct conflict with previous specifications. It was great. I learned a lot about how to create a good coding test :-)
Did you get the gig from Starfleet Academy?
That is a great coding interview. Absolutely nails the field in practice.
still gets under my skin when someone uses a pi for something that really calls out for a microcontroller. but at least it’s useless so the downsides don’t matter.
rp2040
Yes. Binary blob and complex operating system is too complex.
A real PLC would be even more appropriate, assuming you want to get a more sophisticated than plain old relay logic.
A PLC is nothing but a binary blob
…no it’s not? They’re designed, very strictly, to not be unknown or invalid states, fail safe, etc. both at a hardware and software level.
Even better: Use a proper industrial PLC, if plain old relay logic isn’t sophisticated enough.
This is a hydronic elevator?
The future of Cyber Security is assured. Take something simple, transfer it to something seemingly simple. Millions of lines of code, massive attack surface.
How long will it work? Ignore the hardware. Sub software products with their own End Of Life cycle, certificates that have expiration dates 10 years from now?
This mockup is great to demonstrate what an elevator needs to do on the ELI5 level. First this, then that. Great demonstration and it looks like the full user story of the good case is covered.
I hope this never makes it into a real elevator (like a spare one somewhere) . There is none of the failure cases (door sensors, motor sensors, cabin weight), not much on safety, no security and a no software dependency clearing.
Don’t get me wrong – this is impressive and a major effort in getting this far. But it remains a demonstration
I am an actual elevator engineer. I designed the controller hardware and wrote the code using 8085 assembly language starting back in 1985. I implemented up to 32 stops with 256 bytes of RAM, but most were little 2, 3, 4 stop hydraulics. At the 79, I still do tech support for the few thousand of these controllers stiĺ in daily use. part time from home. I am the only one who can do updates to the code. Occasionally, I repair circuit boards.
Don’t die or we’ll die – via pi!
Cool experiment. Well done. Ignore the keyboard patriots’ sarcasm – these guys need some fresh air.
Could he not use the raspberry Pi as the brains of the whole operation and offload the smaller task loads to Pico Pi’s (such as the panels, call switches, safety breaks, and all of those rather small unique individual tasks while everything is coordinated by the single raspberry Pi)? I think that would be much better than using multiple unnecessary raspberry pi’s and be very cost effective. I don’t think you need a full raspberry pi to run every little single small issue but it could coordinate with microcontrollers which are made to do that very type of thing.
Cool work anyway!
AH
I Teach computing to 13 – 16 year olds and cover the full syllabus from networking, through hardware to software , programming and applications with HTML, Scratch and Python thrown in there. I use traffic light control for programming systems as an introduction with breadboards and LEDs on the Raspberry pi. The analysis we do with regard to the safety aspect of the system is basic.
We then move onto level crossing control and up the anti on safety critical programming.
Finally we write the code for an elevator with graphics for the moving parts and using the remote GPIO function we can combine breadboards on wireless PI-Zeros with LEDs to simulate call buttons and floor requests.
The whole purpose of the exercise is to develop the program required with the safety checks and the logical process of the lift operation and then translate that into programming languages.
This is what the PI equipment is designed for to inspire and educate the NEXT generation of professionals in the PLC market place.