# Equipping a microservo with Crocodile clips ## ~ hint If you are conducting a class or group activity, you should consider preparing all servos ahead of time. ## ~ ## Using a microservo with the @boardname@ 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. ### ~ hint 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). ### ~ ## The easy way: Alligator/Crocodile Clip to Male Jumpers #hintconnection The easiest way to connect a servo to the @boardname@ is to use cables with an **Alligator/Crocodile clip** on one end 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. https://youtu.be/XtzsydSTXEg ### Materials * 1 Crocodile clip cable * 1 male (pig tail) cable * Cutting pliers or wire cutter * 1 piece of heat shrink tubing and a lighter Simply cut the cables, strip them, twist the bare wires together, and cover the connection with some heat shrink tubing. ### ~ hint 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.** ### ~ ## Direct connection You can also connect your crocodile clips directly to the servo. ### Materials * Cutting pliers or wire cutter * Tape (masking, duct tape, and/or packing tape) * 3 crocodile clips, yellow, red and black. * 1 micro servo 9g (SG90) ### Step 1: Cut off the connector With the cutting pliers, cut off the dark plastic connector.  ### Step 2: Strip the ends of the cables Using the pliers or a wire stripper, strip the plastic insulation from the cables.  ### Step 3: Twist the wire strands together Twist the strands of bare wire at the ends of the servo cables together.  ### Step 4: Crocodile clip 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!  ### Step 5: Thread the cable ends together Place the cables next to each other...  ... and thread them together.  ### ~ hint 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.** ### ~ ### Step 6: Protect the connection Protect the connection with heat shrink tubing, electrical tape, or duct tape.  ### Step 7: Repeat for all cables Repeat the same process until all cables are connected.  ### Step 8: Testing! 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**. * Connect the microservo cables to these pins on the @boardname@: black to **GND**, red to **3V**, and the remaining cable to pin **0**.  ## ~ hint When attaching the crocodile clips to the pins, don't be afraid to clamp on to the edge of the board with the clips.  ## ~ * Download the following code to your @boardname@. ```blocks basic.forever(() => { pins.servoWritePin(AnalogPin.P0, pins.map( input.acceleration(Dimension.X), -512, 512, 0, 180 )) }) ``` * Test with both power sources and make sure that the servo moves when you tilt the board: >* Connected with USB. >* Powered by batteries **only** and not connected with USB. ## Calibrating Use the [servo calibrator](/projects/servo-calibrator) program to determine the best angles to use for your make. ## Troubleshooting 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.