145 lines
5.1 KiB
Markdown
145 lines
5.1 KiB
Markdown
# Equipping a microservo with Crocodile clips
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## ~ hint
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If you are conducting a class or group activity, you should consider preparing all servos ahead of time.
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## ~
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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. This servo requires 3 connections: **GND**, **3V** and a logic **pin**. In this tutorial, we will equip the servo with crocodile clips to make it easier to use. However, you could also use a shield or crocodile clips with a male connector on one end to achieve the same result.
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### ~ hint
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To better understand how servos work and how they are controlled, take a few minutes to read this [Brief Guide to Servos](https://www.kitronik.co.uk/pdf/a-brief-guide-to-servos.pdf).
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### ~
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## The easy way: Alligator/Crocodile Clip to Male Jumpers #hintconnection
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The easiest way to connect a servo to the @boardname@ is to use cables with an **Alligator/Crocodile clip** on one end
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and a **Male jumper (pig tail)** on the other end. You can purchase bundles these cables from various electronic resellers or easily build some as shown here.
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https://youtu.be/XtzsydSTXEg
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### Materials
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* 1 Crocodile clip cable
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* 1 male (pig tail) cable
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* Cutting pliers or wire cutter
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* 1 piece of heat shrink tubing and a lighter
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Simply cut the cables, strip them, twist the bare wires together, and cover the connection with some heat shrink tubing.
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### ~ hint
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It is very **important** to ensure a good connection between the 2 cables. If the connection is weak, the microservo will not receive enough current and it will not work. **If you have access to a soldering iron, we strongly recommend that you solder this connection.**
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### ~
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## Direct connection
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You can also connect your crocodile clips directly to the servo.
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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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### Step 1: Cut off the connector
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With the cutting pliers, cut off the dark plastic connector.
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### Step 2: Strip the ends of the cables
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Using the pliers or a wire stripper, strip the plastic insulation from the cables.
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### Step 3: Twist the wire strands together
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Twist the strands of bare wire at the ends of the servo cables together.
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### Step 4: Crocodile clip
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Cut a crocodile cable in two and strip off the insulation. If it's possible, try to use cables with colors that match the cables on the servo!
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### Step 5: Thread the cable ends 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. If the connection is weak, the microservo will not receive enough current and it will not work. **If you have access to a soldering iron, we strongly recommend soldering this connection.**
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### ~
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### Step 6: Protect the connection
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Protect the connection with heat shrink tubing, electrical tape, or duct tape.
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### Step 7: Repeat for all cables
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Repeat the same process until all cables are connected.
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### Step 8: Testing!
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It's time to test and find out if your connections are all secure and that the servo will function **when the @boardname@ is powered by battery**.
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* Connect the microservo cables to these pins on the @boardname@: black to **GND**, red to **3V**, and the remaining cable to pin **0**.
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## ~ hint
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When attaching the crocodile clips to the pins, don't be afraid to clamp on to the edge of the board with the clips.
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## ~
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* Download the following code to your @boardname@.
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```blocks
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basic.forever(() => {
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pins.servoWritePin(AnalogPin.P0, pins.map(
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input.acceleration(Dimension.X),
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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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* Test with both power sources and make sure that the servo moves when you tilt the board:
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>* Connected with USB.
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>* Powered by batteries **only** and not connected with USB.
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## Calibrating
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Use the [servo calibrator](/projects/servo-calibrator) program to determine the best angles to use for your make.
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## Troubleshooting
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If your servo seems to stutter and remain stuck at a particular position, it means that it's not receiving enough power. This is probably due to a weak connection or low battery level. Make sure that each connection is good and check your batteries.
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