2017-01-05 19:00:36 +01:00
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# Preparing the servo
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### @description Connecting the servo to crocodile clips
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### ~avatar avatar
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Equip the microservo with crocodile clips.
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### ~
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## Duration: ~30 minutes
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## Materials
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* Cutting pliers or wire cutter
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* Tape (masking, duct tape, and/or packing tape)
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* 3 crocodile clips, yellow, red and black.
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* 1 micro servo 9g (SG90)
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## Using a microservo with the @boardname@
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The @boardname@ provides just enough current to operate the SG90 microservo.
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The servo requires 3 connections: GND, 3V and a logic pin.
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In this tutorial, we will equip the servo with crocodile clips to make it easier to use.
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However, you could also use a shield or female to crocodile clips to acheive the same effect.
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If you are running a class or activity, you should consider preparing all servos before hand.
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### ~ hint
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Kitronik wrote an excellent in-depth guide about using servos with the @boardname@.
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2017-01-05 22:28:06 +01:00
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Check it out at https://www.kitronik.co.uk/blog/using-bbc-microbit-control-servo/ .
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2017-01-05 19:00:36 +01:00
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### ~
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## Step 1: cutout the connector
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Using the cutting pliers, cut out the dark plastic connector.
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## Step 2: strip out cables
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Using the plier or a wire stripper, strip the plastic from the cables.
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2017-01-06 15:12:39 +01:00
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2017-01-05 19:00:36 +01:00
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## Step 3: threading the servo cablers
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Thread the servo cables.
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## Step 4: crocobile clip claps
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Cut a crocodile cable in two and strip out the casing.
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If possible try to use the same cable colors as the servo!
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## Step 5: thread cables together
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Place the cables next to each other
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... and thread them together.
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### ~ hint
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It is very **important** to ensure that there is a good connection between the 2 cables.
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If the connection is weak, the microservo will not receive enough current and it will not work.
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If you have access to a soldering iron, we strongly recommend to solver this connection.
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### ~
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## Step 4: protect the connection
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Protect the connection with electrical or duct tape.
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## Step 5: repeat for all cables
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Repeat the same process until all cables are connected.
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## Step 6: testing!
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It's time to test that your connection are all proper and that the servo will function **when the @boardname@ is powered by battery**.
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* Connect the microservo to the @boardname@. Black cable on ``GND``, red cable on ``3V`` and remaining cable on ``P0``.
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### ~ hint
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When attaching the crocodile clips to the pins, don't hesitate to grab the side of the board with the jaws.
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### ~
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* Download the following code to your @boardname@
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```blocks
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let a = 0
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basic.forever(() => {
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a = input.acceleration(Dimension.X)
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pins.servoWritePin(AnalogPin.P0, pins.map(
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a,
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-512,
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512,
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0,
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180
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))
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})
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```
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* When powered by USB, make sure that the servo moves when you tilt the board.
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* When powered by batteries **only**, make sure that the servo moves when you tilt the board.
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If your servo seems to sutter and stay stuck at a particular position, it means that it is not receiving enough power.
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This is probably due to a weak connection or low battery level. Check each connection and check your batteries.
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### ~button /projects/inchworm/chassis
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NEXT: Chassis
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### ~
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