Introduction: Motion Module

Picture of Motion Module

The motion module is the most complex photocoupled device used in Simple Bots. It basically is a light switch coupled with a motion sensing nightlight. When someone in its general area moves, this triggers the sensor, turns on the light, and causes the bot to move. This is a simple way to start adding more complex behaviors to your bots and have them respond to their environment.

Step 1: Go Get Stuff

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You will need:

- Motion sensitive nightlight (battery operated)
- Simple Light Switch
- Electrical tape

Step 2: Drill

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Drill a 1/4" hole in the protective lens directly above one of the night light's LEDs.

Step 3: Insert and Glue

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Place the light switch face down into the hole such that the lens of the switch aligns with the lens of the LED.

Hot glue it in place.

Step 4: Cover

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Cover the entirety of the night light's lens with black electrical tape, to black out any ambient light from the room.

Step 5: Remove the Cover

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There should be a fresnel lens covering the PIR (motion) sensor. This should appear to be a plastic honeycomb material.

Remove this lens, to expose the PIR sensor.

Step 6: Hack the Sensor

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The sensor should appear to be a round metal tube with a shiny square in the middle.

What you really want to modify is the light sensor which is located next to the motion sensor. The light sensor should look like a flat disc with interwoven teeth on it or a clear LED (like our own simple light switch).

The light sensor is what allows the motion sensor to know that it is nighttime and should activate. We want the night light to always think it is nighttime. In order to do that, we need to cover the light sensor with electrical tape.

Step 7: Reassemble

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Put the fresnel lens back on and it should now be good to go.

Remember that the longer lead from the simple light switch should go towards the positive side of the circuit and the shorter lead should go towards ground.


bfk (author)2012-06-01

Beautiful description and photos (all of your stuff)... Hope you're proud of yourself... You've gone and got me interested in robotics.:)

About This Instructable




Bio: My name is Randy and I founded the Instructables Design Studio. I'm also the author of the books 'Simple Bots,' and '62 Projects to ... More »
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