OM2 shield
OM2 is our basic board with the following features:
- one H bridge set up to drive a single stepper motor (e.g. for a whisker stimulus)
- one H bridge able to control up to four 12V solenoid valves (for liquids or air)
- lick sensing via the MPR121 capacitive touch sensor (available from Sparkfun)
- speaker output for cue tones (generated by the arduino)
- servo motor output (e.g. for driving linear actuator to move stimulus or lick port into place)
The basic idea of OM2 (and all of the shields we've designed) is to connect the various inputs and outputs on the Arduino to external hardware, such as touch detectors or stepper motors. Then, you can program the Arduino to control this hardware in a variety of different ways, depending on the specific behavioral task you want.
OM2 is loaded with different components (resistors, transistors, integrated circuits or ICs, etc.) which are wired into the Arduino inputs and outputs.
Here is the wiring diagram:
Components List
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Two H-bridges
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Two 16-pin IC sockets for the H-bridges to sit in
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One MPR121 (optional, only for touch/lick detection)
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Long strip of 0.1" female headers, which you can cut to size
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Double height header pack for Arduino UNO.
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18G (check?) wire and wire strippers
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Two BJTs (NPN, like 2N2222A)
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Resistors (2x 1k, 2x 10k ohms)
Making the shield
To make OM2, you have two options:
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Order a printed circuit board (PCB) using the design files we provide below. You will still need to attach the components; however, you don't need to do any wiring because the connections are already printed on the PCB.
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Order a proto-board from Sparkfun, and attach all the components yourself.
The advantage of wiring everything yourself is that you'll understand it more completely, and you don't need to deal with uploading the PCB design. The advantage of the PCB is that it takes less time to attach the components and the shields will be more consistent. If you're making more than four or so shields, the cost comes down drastically and the PCB route becomes very attractive.
Here is the protocol for printing OM PCBs at Seeed Studios.
Attaching the components
Once you have all the components, simply place them on the shield. If you're using a PCB, place the components in the holes that are marked, and they will already be connected. If you're using a proto-board, place them anywhere on the shield and connect to the appropriate pins using wires.
Using the shield with the Arduino
You can use example code from the tactile task, but you have to remove the control code for the second stepper motor.