Determine Dumb Waiter Level

We have a dumb waiter/mini elevator in our building that goes between 4 floors. We'd like to track it's progress over a day. Is there a sensor that would do this i.e. tell us roughly which level it's on? Z-Wave altitude or something hacked together?

One option would be 4 door/window sensors--one for each floor. Which ever one of the four is "closed" would be the floor it's on. You could put each on one of the four corners so that they would have no chance of tripping the wrong floor's sensor.

With a decent price, you could do the whole thing for under $100.

Dave

I like Dave's suggestion.

Depending how the device is summoned/called, another option might be switch/input sensors shorted across the call/send buttons? The last button pressed indicates which floor it's at.

And now for something completely different.

Mount distance sensors (IR or sonic) at the top and bottom of the shaft. I'd use two to average the two readings for better accuracy. If you use ±5v sensors you can read them with a Phidgets InterfaceKit, an Arduino or a R-Pi (or similar) with an analog board. You can also use hall-effect sensors at each landing for positive identification of the car's position.

To interface with Indigo you'd just need an external script to monitor the sensor values and update variables. You could also create a plugin, but I doubt it would be worth the extra effort. A little logic would tell you if the car was moving, and ifs, in which direction it was traveling.

Good luck, sounds like a fun project.

I wondered about a distance approach, but didn't know of any suitable hardware.

Ultrasonic sensors will not work in the dumb waiter's shaft (excuse the double entendre) because of the echos that will be introduced by the reflections off the walls. I have some personal and professional experience in the area and can tell you that it's very difficult and gets expensive quickly. I'd go with Dave's suggestion of door/window sensors at each location, or if I wanted distance sensing down to the fraction of an inch I'd mount a rotary encoder on the pulley or at the motor.

Hmm- maybe I can find a sensor that counts distance to another like an iBeacon. Thanks for the suggestions!

INSTEON 2843-222 WIRELESS OPEN/CLOSE SENSOR or equivalent if you are zwave. Add one magnet on the lift and 4 of the sensors at the stop points. Off=the floor its on.


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INSTEON 2843-222 WIRELESS OPEN/CLOSE SENSOR or equivalent if you are zwave. Add one magnet on the lift and 4 of the sensors at the stop points. Off=the floor its on.

I was thinking the same thing, only in reverse. I was thinking having the sensors on the dumb waiter would make it easier to service them (change batteries, includes, etc.)

Dave

That may work. How would you know the floor level with only one sensor? On/off is the trigger so on/off at floor 1 would look the same as on/off at floor 4. I guess you could set a incremental script logic but I am struggling to come up with it. Floor 1 is zero next off is + 1 but what if it retuned to floor 1. How would we know the next off would be up a floor or down a floor? Another thought would be an I/o link. Metal trips at each floor that are hard wired back to the I/o. That would reduce your longer term maintenance and give the logic you are looking for. Each level can be one input trigger.


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Was thinking four sensors (one on each corner) but your post made me think of something that I hadn't considered. Depending on the configuration of the network, it could become confused with the sensors moving vertically through the building by 40 feet or more. That actually might be a deal-breaker for putting the sensors on the car.

Something else to consider, anyway.
Dave

Yes, silly me. After looking at your post that's exactly what you were saying. Agree on the network. Perhaps a repeater half way if signal is a problem. Was also thinking you may only need two sensors on floor 2 and 3. Logic could then be used to solve for 1st and 4th. Less cost, distance, and hardware.


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