I'm brainstorming a project idea to streamline some processes in a production facility. I have about 10 manufacturing lines that fill empty bottles with liquid product. They are located in a large clean room that is a few hundred feet away from the maintenance shop. When the machine goes down and needs a mechanic to fix it, the operator has to remove their smock and physically go to the maintenance shop to find a mechanic.
I would like for the operator to be able to press a button on the machine that will cause a corresponding light to be illuminated in the maintenance shop through a wireless signal. Additionally, if the operator presses a different button, a light will illuminate in another room that signals that the machine is ready for a changeover.
I would like to have each machine be able to send signals to at least 3 different light boards that indicate different needs. Wifi is available to all the areas in question, as well as wired network connections. I'm just hoping to get some ideas on how this could be accomplished. I'm probably a little over my head with this project, but would like to get some ideas of how this could be accomplished. Any input is appreciated.
The ESP8266 WiFi devices are cheap and can be programmed using the Arduino IDE.
If you are using WiFi why not use it to display messages on the operators' browser screens.
...R
You could always get your operators to use a mobile phone....
regards
Allan
allanhurst:
You could always get your operators to use a mobile phone....
I suspect the bigger problem is to stop them 
...R
You could issue them with works only ones with a limited preset of diallable numbers - these are available for disabled people....
regards
Allan
ps : I don't mean to be rude to the employees!
pps : Aren't there internal factory landline phones on the shop floor?
Install a dedicated PLC to provide the switch inputs and alarm outputs.
Factories want gear that is "industry standard" so that it can be installed and maintained by people with trade skills.
Any solution requiring microcontrollers and C programming would be a last resort unless you already have people on staff doing this sort of stuff.
Lot's of ways to do this, but technically not very difficult. Much depends on how many objects are between the machine and maintenance, any Ethernet near the machines, etc.
Some transceivers are not good at sending data when buildings are in the way, but nRF24L01 with high gain antennas may work.
Sending commands via Ethernet may be an option
Sending commands to a phone/browser, etc. is another route.
If you have any more details regarding distances, communication, etc. we may be able to give more guidance.
mikb55:
Install a dedicated PLC to provide the switch inputs and alarm outputs.Factories want gear that is "industry standard" so that it can be installed and maintained by people with trade skills.
Any solution requiring microcontrollers and C programming would be a last resort unless you already have people on staff doing this sort of stuff.
All very wise advice.
...R
Given it's a factory there may be loads of steel framework and cladding, with highly unpredicable propagation.
I'd want to do a proper survey before recommending a radio solution.
Landlines could be a reliable answer, perhaps signalling faults via modems.
regards
Allan
Wi-Fi is still viable (and probably the cheapest/fastest way) to do this the way you framed the question. Think 'closed loop'.
The trick is to make each 'machine' node aware of its relationship to the 'server', such that messages are not lost due to interference etc.
i.e. Machine Operator presses a Maintenance/Changeover button, message is sent.... then only when server / maintenance office receives and acknowledges the request - is the ACK sent back, and the operator informed the request has been successful.
Tech arrives, clears the request... (machine is still offline), completes the work and sets the 'completed' state (machine is available back online).
You can take this a little further, with a log of requests, completion time and message loop integrity. Well, i would.
I would say Allen Bradley is probably the way to go