130 lines
3.5 KiB
Markdown
130 lines
3.5 KiB
Markdown
# Preparing the servo
|
|
### @description Connecting the servo to crocodile clips
|
|
|
|
### ~avatar avatar
|
|
|
|
Equip the microservo with crocodile clips.
|
|
|
|
### ~
|
|
|
|
## Duration: ~30 minutes
|
|
|
|
## 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)
|
|
|
|
## Using a microservo with the @boardname@
|
|
|
|
The @boardname@ provides just enough current to operate the SG90 microservo.
|
|
The 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 female to crocodile clips to acheive the same effect.
|
|
|
|
If you are running a class or activity, you should consider preparing all servos before hand.
|
|
|
|
### ~ hint
|
|
|
|
Kitronik wrote an excellent in-depth guide about using servos with the @boardname@.
|
|
Check it out at https://www.kitronik.co.uk/blog/using-bbc-microbit-control-servo/ .
|
|
|
|
### ~
|
|
|
|
## Step 1: cutout the connector
|
|
|
|
Using the cutting pliers, cut out the dark plastic connector.
|
|
|
|
|
|
|
|
## Step 2: strip out cables
|
|
|
|
Using the plier or a wire stripper, strip the plastic from the cables.
|
|
|
|
|
|
|
|
## Step 3: threading the servo cablers
|
|
|
|
Thread the servo cables.
|
|
|
|
|
|
|
|
## Step 4: crocobile clip claps
|
|
|
|
Cut a crocodile cable in two and strip out the casing.
|
|
If possible try to use the same cable colors as the servo!
|
|
|
|
|
|
|
|
## Step 5: thread cables 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 to solver this connection.
|
|
|
|
### ~
|
|
|
|
## Step 4: protect the connection
|
|
|
|
Protect the connection with electrical or duct tape.
|
|
|
|
|
|
|
|
## Step 5: repeat for all cables
|
|
|
|
Repeat the same process until all cables are connected.
|
|
|
|
|
|
|
|
## Step 6: testing!
|
|
|
|
It's time to test that your connection are all proper and that the servo will function **when the @boardname@ is powered by battery**.
|
|
|
|
* Connect the microservo to the @boardname@. Black cable on ``GND``, red cable on ``3V`` and remaining cable on ``P0``.
|
|
|
|
|
|
|
|
### ~ hint
|
|
|
|
When attaching the crocodile clips to the pins, don't hesitate to grab the side of the board with the jaws.
|
|
|
|
|
|
|
|
### ~
|
|
|
|
* Download the following code to your @boardname@
|
|
|
|
```blocks
|
|
let a = 0
|
|
basic.forever(() => {
|
|
a = input.acceleration(Dimension.X)
|
|
pins.servoWritePin(AnalogPin.P0, pins.map(
|
|
a,
|
|
-512,
|
|
512,
|
|
0,
|
|
180
|
|
))
|
|
})
|
|
```
|
|
|
|
* When powered by USB, make sure that the servo moves when you tilt the board.
|
|
* When powered by batteries **only**, make sure that the servo moves when you tilt the board.
|
|
|
|
If your servo seems to sutter and stay stuck at a particular position, it means that it is not receiving enough power.
|
|
This is probably due to a weak connection or low battery level. Check each connection and check your batteries.
|
|
|
|
|
|
### ~button /projects/inchworm/chassis
|
|
NEXT: Chassis
|
|
### ~ |