Saturday, January 7, 2017

LogoTurtle Bump Sensor


I designed a bump sensor bracket for the LogoTurtle that you can 3D print and add to your LogoTurtle. The model was designed for the laser cut version of the chassis. However, with longer battery holder screws it could easily be attached to the 3D printed chassis as well.

The bump sensor is built around a small rocker switch.


I soldered two wires to the switch and soldered the wires to the LogoTurtle board. The ground connects to pin A2 on the Metro Mini through a 10K resistor. The positive wire from the switch connects to the positive rail on the LogoTurtle board.


The switch sits behind a tongue depressor that has two one inch springs behind it. The switch activates if the bumper is pressed nearly everywhere along its length. The sensitivity of the switch can be configured by moving the rocker switch closer (or farther) from the bumper.




A simple Logo procedure can be uploaded to the LogoTurtle to have the turtle drive until the switch is activated. This example backs up 200 then turns somewhere between 10 and 360 degrees before going forward again. This procedure could be made more "sensitive" by having the LogoTurtle drive a shorter distance before it polls the switch data.
to startup
loop 
[bump]
end

to bump
ifelse a2 > 1000
[bk 200 rt random 10 360]
[fd 100]
end
This addition to the LogoTurtle adds functionality to this robot: in addition to making beautiful art, the LogoTurtle now can be programmed to behave as a roaming, autonomous robot capable of navigating flat terrain with obstacles. 

3D print yourself a bracket and upgrade the functionality of your LogoTurtle!

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