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Second Arduino project

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  • Second Arduino project

    One of the sensors that I previously built lives in my 'mudroom/utility/mechanical' room. The new sensor there now looks for motion and turns on lights. The door has a sensor of its own that triggers security as well as lights. Hope to add temp and air sensors.

    Going to start a new project which will add functionality to the mudroom node to be able to control the hot water heater and the well pump. Both are 240v. Use case is:
    1. When I am away, why waste electricity to heat water. (ACK potential debate).
    2. In winter, and this is important, be able to turn off well pump when not home to prevent flooding should a pipe break. Requires turning off hot water heater at the same time for safety reasons. Also needs to turn off water conditioner but already got that covered with an Insteon device.

    If I have a HS3 device, I can view/control it remotely with HSTouch. No issue there.

    But, this project is going to enter the high voltage arena so extra safety considerations are required. Going to start with the HW heater.

    I got two of these devices:

    $10 for the two of them. Hot water heater is interesting in that there is no common (white) wire. Just 2 120V legs and a ground. 10 years ago I got an insteon high voltage controller for the HW heater and got stumped when there was no common. Fast forward today, two of these new switches controlled by my underutilized mudroom arduino might work out nicely.

    On the breadboard, the UNO as well as the nodeMCU is controlling the devices as verified by onboard LED - but with no load. Since I want them to go on/off at the same time, I am wiring them parallel. Control one, control both.

    Anybody have any experience with controlling a 240v hot water heater? Thoughts??

  • #2
    Looks like what you have is a solid state version of a contactor. I use arduinos to turn/off my well pumps, air compressor, and electric heat in the bard with 2 pole contactors with 24VAC coils. You use a 24VAC telephone transformer. It is plugged in 24X7 and connected to one side of the contactor coils. The other side is connected to a latching relay the arduino controls. The latching relay keeps it's state without power applied. I apply power for 3 seconds, then remove power, and the relay is latched open or closed.

    When closed it completes the cotactor coils and engages the device (110V or 220V as it is a 2 pole contactor. In theory you can manage 110V devices with a single pole, but I get 2 pole for most flexibility. I can have Alex control now!

    I also use latching sprinkler valves to turn water on/off to remote devices with an arduino and an h-bridge.

    I'm using the API version to measure water level in my water storage tank with with an ultrasonic distance sensor. I measure the current the down hole and in-tank well pumps are pulling with inductive sensors. They clamp around one wire and need 4 resistors and one capacitor to make work. Minimal coding with the EmonLib. I use onewire for temp as well.

    Without walking 1000ft to check the well I can tell if either of the pumps are on, water level in tank, turn off a well pump as needed, and temperature. Applying icons for sensor ranges I can see green/yellow/red status and have HS3 test me when anything goes yellow or red.

    I then added a water sensor in the breaker box ... if the talk overflows, water goes int the bulkhead fitting for electric and into the breaker box. If I detect water there I turn off all pumps.

    If I detect 35F temps or lower HS3 uses zwave to turn on the outlet with the heat wire. I could do this with Arduino, but I had the z-wave ethernet bridge and a z-wave outlet.

    I'm working on adding two hall effect current sensors to a 34 CU IN 2-gang box so I can directly measure current of 110V devices. Looks easy enough, I just need to attach the hall effect sensors, wires back to the ardunio, and calibrate.

    My last new thing to do is use an analog pressure sending unit and connect to the arduino. It will tell me the pressure on the swimming pool tank that I use to filter my well water. In theory higher circulation pump amperage with higher pressure readings will indicate the filter is getting clogged. Once I find sweet spots, I can program green, yellow, red status colors to tell me when to clean.

    My NodeMCU project is a knock-off of the OpenGarage device that connects fully to H#s so I know if the garage is open, closed, and if a car is in if closed. I should be able to identify my truck vs. wife's car, Then have the ability to open and close the garage door. With my phone and the "Android AVS" Ubi app I can talk to my phone and open the gate, garage door, etc.

    This stuff is ADDICTIVE!!!!


    • #3
      Originally posted by cowsr4eating View Post
      This stuff is ADDICTIVE!!!!
      I agree with that statement. If you are a 'builder' (new term 'maker'), it is a low cost, challenging, and potentially useful area for projects. I've got 10 installed and am running out of motivating projects. Lots of usefulness but not so many new challenges. Looking at sonoff as well as energy usage monitoring. The energy is an interesting field but I'm not sure how actionable it is.