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Turning on a machine automatically when another machine is turned on - using ad hoc ESP8266 network

donnybahama

I’m very new to microcontrollers and programming. I probably know just enough to be dangerous. I’m trying to devise a reasonably simple system for turning on the dust collector in my wood shop and positioning the sliding carriage (output side) of a blast gate manifold over the appropriate inlet for the tool that was just turned on. (The first 10 seconds of this video will clarify how the manifold works.)

The way I think I want to do this is using an ad hoc network of ESP8266 modules - 6 “sender” modules which send "Power ON” and [Machine ID] to the “receiver” module (mounted near the dust collector and blast gate manifold) when current is detected for the dust producing machine’s motor. The receiver module then triggers a relay which turns on a motor which turns a threaded rod which moves the manifold’s sliding carriage to position it over the inlet for the tool that was just turned on. Six reed switches - one each attached to the blast gate inlets - are connected to GPIO pins on the receiver module. A magnet mounted to the sliding carriage closes each reed switch as it travels. When the ESP8266 sees that the reed switch for the desired GPIO pin has been closed, it 1) deactivates the relay that’s supplying power (or ground) to the positioner motor, 2) activates a relay that turns on the dust collector, and 3) Turns on a green indicator that can be seen throughout the shop, indicating that the dust collector is on and the proper blast gate is open.

If that’s not the right way to do things, please let me know what the right way is.

Things I need guidance on:

  1. Because I have zero experience with microcontrollers and GPIO pins, I’m not exactly sure what the microcontroller expects to see on a GPIO pin in order to know that some trigger just occurred and some action must be taken. Does it want to see voltage? Ground? A particular frequency?
  2. The “sender modules send “Power ON” ad the machine ID to the receiver module when current is sensed. What’s the simplest/cheapest way to detect the current from a motor turning on and use that to trigger the GPIO pin?
  3. Again, because I have no experience programming a microcontroller, how do I tell the microcontroller to ignore the (momentarily) closed reed switches from the other manifold inlets as the carriage/magnet travels by reed switches 1, 2, and 3 to get to the desired (#4) position?
  4. Anything else I’m overlooking?

Thank you for your time and consideration.

Parents

  • Perhaps best to start with Question 4...

    - Safety. Power tools, mains power and "new to microcontrollers and programming" can quickly result in injury.

    - Your 5th port (free hose) doesn't have a power line to sense in order to activate, so you will need some sort of override switch for that. Even if it is the default position when no tool is being used, then you still need to turn the shop vac on and off. 

    - Handling unplanned conditions - two machines are turned on at the same time. 

    - Manual over-ride - how do you operate the manifold manually when your microcontroller solution stops working and it is driven by a threaded rod.

    - Limit switches - if using a threaded rod then you may want separate hard-wired limit switches to stop the motor if your programming fails to detect the port reached sensor and keeps on going, which usually doesn't end well.

    - Power on states - your system could power up with the manifold position not on any sensor, so your initialisation routine will need to work out where it is so you may want soft limit sensors in case you end up past the outer ports.   

    - Motor controller - you will need a suitable motor controller between the microcontroller and the motor which can drive the threaded rod in either direction.

    - Mechanical switch de-bouncing - mechanical switches tend to bounce which can give unexpected behaviour in your programming.

    Question 3 I don't think is an issue, as if you turn machine 4 on you will likely be checking to see if machine 4 power sense is active AND port 4 sensor reached. Your program will likely be ignoring any activity on port sensors 1-3 as it passes them.

    Any reason that you have chosen the ESP8266 for this ? Sounds like you are perhaps planning on Wi-Fi connectivity ? However if you are already committed to running large vacuum hoses to each machine then a wired solution could be simpler / more reliable for starting out.    

  • in reply to beacon_dave
    beacon_dave said:
    if you are already committed to running large vacuum hoses to each machine then a wired solution could be simpler / more reliable for starting out

    A wired solution probably does make more sense. This project would be fun and interesting and a great opportunity to learn new stuff - but I do tend to gravitate toward simplicity and reliability in my shop.

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