Hi, for a large project for a 100 slot parking supervision system there need to be 14 7-segment/2 digit 7" display panels each showing different values (ie free slots for specific and different parking segments).
The hardware supervises sensors (1 per parking slot) giving real-time either "vacant" or "occupied" status for each slot to the control system.
The parking consists of 2 underground floors of 60x40m size. The panels will be situated on distances of >100m from the controlling pc.
What I look for is a solution that allows my programmer to address each panel individually and transmit a specific 2-digit number to each panel.
I know there are drivers for 7-segment displays but I need to have a solution to address these display panels individually. Similar to large highway display panels showing the price for different fuels at the next petrol station.
My programmer uses C++, the software will be installed on a W10 pc, but the information needs to get out of this pc to the display panels and their individual drivers.
The controller W10 pc is situated about 50m from the actual parkings. The addressing of the individual display panels can go over TCP/IP.
Question: How would this on hardware level best be accomplished, with what best solution for hardware drivers?
brice3010:
Hi, can you give some examples (ie url?) for this please?
TCP/IP with cat5 or cat6?
Oh, you want to use Ethernet. Isn't that kind of overkill to just change a few digits? How will you daisy chain, (because Ethernet doesn't support that without multiple ports and retransmission)? Are you concerned about cost?
aarg:
Oh, you want to use Ethernet. Isn't that kind of overkill to just change a few digits? How will you daisy chain, (because Ethernet doesn't support that without multiple ports and retransmission)? Are you concerned about cost?
Costs: laying cat5 ethernet cable or twisted pair RS422 or 485 cable is the same cost (labour)
Addressing of controllers (1 per display) should not be too hard over ethernet?
Rs485 and CAN bus are used to connect all the bits together.
Thank you but your response does not answer my initial question.
The link you gave is for a wired system for sensing parking lot occupancy for which i already have a solution; and there is no mention of display panels at all.
The point aarg is trying to make is that laying ethernet will be more expensive than rs485 even if you use the exact same cable, because you will have to lay more of it, in a star configuration coming out from a hub, and pay for the hub. With rs485, you can daisy chain all the displays one to the next, leading back to a single station connected to the PC via serial.
Is WiFi an option? Is it already present (unlikely in an underground car park,I know)? Would one WiFi access point per floor cover all displays? Maybe with a couple of boosters? If the signal was weak and slow for the most distant displays, that's still way fast enough for the use case. If so, you could use esp8266 based boards to drive the displays, such as Wemos Mini. If signal strength is an issue, the Wemos Mini Pro can accept an external high gain antenna. Each display could be given a fixed I/p address and could act as a server, accepting updates via an http or UDP request.
Have you already sourced some 7" 7-seg displays? They may be hard to find. You may have to make them from 12V led strips. Tpic6b595 chips could drive each digit.
brice3010:
Thank you but your response does not answer my initial question.
The link you gave is for a wired system for sensing parking lot occupancy for which i already have a solution; and there is no mention of display panels at all.
OK. But that looks remarkably like a display panel to me and if you have solved the problem of integrating numerous sensors into your system (by whatever means which you have not mentioned), why not use the same technology to integrate the displays.
Anyway, good luck in finding a solution.
Have you already sourced some 7" 7-seg displays? They may be hard to find. You may have to make them from 12V led strips. Tpic6b595 chips could drive each digit.
The fact that cabling is to be laid out in star versus in chain does not affect the labour cost for laying cable for such a large system. We can then better choose for the best communications concept and maybe pay a bit more, since in the long run that will pay back itself in less headaches.
No, wifi is not an option: the surface is too large, too many obstacles, too high risk for interference, cost,...
Our supplier today has sourced tcp/ip driven displays with text possibilites; USD175 FOB (see photo), but worth the cost since the whole project is budgetted at USD35.000
Thank you for your input, but since this is a professional project there is not much room for self-made items; the reason I ask my questions here is to look for concept ideas for the direction in which to search for solutions on specific items such as these displays.
But I will gladly look at any further comments of improvements on the current concept, I keep an open mind.
6v6gt:
OK. But that looks remarkably like a display panel to me and if you have solved the problem of integrating numerous sensors into your system (by whatever means which you have not mentioned), why not use the same technology to integrate the displays.
Anyway, good luck in finding a solution.
You are right, I had not seen that. In fact what I am looking for, except that here it already is integrated in an existing system and therefor not possible to use in different systems. As far as the concept of this display panel goes, I need to have a closer look at the way these comlmunicate with the central control system.
PaulRB:
(...)
Have you already sourced some 7" 7-seg displays? They may be hard to find. You may have to make them from 12V led strips. Tpic6b595 chips could drive each digit.
Thee can be found on Aliexpress, USD20 for five.
That was a route I had been looking at (7" displays driven by Tpic6b595), until I received info this morning about fully integrated TCP/IP displays.
Anyway thank you for your input, it will probably serve infuture projects.
