motion sensor with motor

Discussion in 'The Projects Forum' started by Mori, Jan 26, 2013.

  1. Mori

    Thread Starter New Member

    Jan 26, 2013
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    I'm working on a sculpture. I am using a conventional motion sensor and a small motor to move the tail of a cat. It seems to work for awhile then the motor stops and I need to "jump" start it by turning on the motor with the batteries that are attached.

    So the line starts with an extension cord from the wall. It plugs to a motion sensor with a line that I plugged a multiple plug outlet. In one outlet is the line to the motor (there are some gears before the motor because it was taken from a small horse toy - so it has a battery pack). In the other outlet is a small lightbulb. The lightbulb was a suggestion from my father and also lets me know that the motion sensor is working. The motor turns on an moves a tail.

    My father was an engineer and used to help me with these things. I remember him saying that I might need a light between the light and the motor so I put a light on the same plug next to the adaptor for the 3 volt motor. It's not really "in line" with the motor it is more parallel.

    So i turn on the motion sensor, it goes for maybe 10 minutes then I see that the light is on but the motor won't go on. If I go and turn on the switch that lets the battery power the motor, it starts working. Then I turn that off and the motor keeps working from the outlet.

    This is going to be in a museum so I really want this to work without having to do this extra step of going inside the sculpture to get the tail going again. I have a little diagram but I have to go through one more step to post that with this message.

    What am I missing that makes it work? :confused:

    Any help would be greatly appreciated. But a lot of these forums are way over my head. So if you have suggestions please help by giving me simple directions.
     
  2. #12

    Expert

    Nov 30, 2010
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    As a rough guess, the power from the sensor seems insufficient. Motors require a start surge that may be in excess of the power supply you have provided. The batteries can "kick start" the motor but the power converter might be a bit too small.
     
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  3. Mori

    Thread Starter New Member

    Jan 26, 2013
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    Thank you. That makes sense.

    Okay, a bit more information. So when I say it works for 10 minutes, it's working and turning off and on as I walk around the studio. So it's not necessarily getting that kick during that time. I just did the same loop again of starting the motor with the battery, then it turned off and on, and now it's off. The little light is on so I know it's sensed my motion.
     
  4. #12

    Expert

    Nov 30, 2010
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    Get the diagram up here and I will not have to try so hard to guess what's wrong.
     
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  5. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    #12 is probably correct: the power adapter for the motor is too small. Look at the adapter, and post what the label on it says with regard to input and output (voltage and current.) Also post how many and what size batteries are used to normally power the motor.
     
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  6. Mori

    Thread Starter New Member

    Jan 26, 2013
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    Thank you so very much. There is a link now with photos and the diagram.

    The adaptor is 3volts and the toy parts used 2 AA batteries so 2.4 volts. I had a device my father made me to lower the voltage. I removed this and now it seems to be working.

    However, when it's off there is still a slight current. The light dims and the motor is going slowly. I changed the bulb from the big one to a smaller bulb. (not sure I needed to mention that)

    So you were right that it needed that kick. When it senses motion it moves more and the motor is going faster than it was on the batteries.

    This piece will be on display for months. So ideally I want it to turn all the way off and save the motor.

    [​IMG]
     
  7. Mori

    Thread Starter New Member

    Jan 26, 2013
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    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    I posted the link to the album page, but it wanted them to each photo.
     
  8. Mori

    Thread Starter New Member

    Jan 26, 2013
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  9. #12

    Expert

    Nov 30, 2010
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    (2) AA batteries make 3 volts.
    The leakage current is coming from the motion sensor. (Naughty motion sensor!)
    Either try a different motion sensor or add a load to use up the leakage current, like a hidden light bulb that runs on 3 volts.
     
  10. Mori

    Thread Starter New Member

    Jan 26, 2013
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    0
    I will try adding a light in with the motor and see if that fixes the leakage. And if that doesn't work, I'll try getting another sensor.

    Thank you so much! I really appreciate this help so much. I was feeling rather lost in how to go forward.
     
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