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j5-delta

J5-Delta

Delta Robot Component for Johnny-Five

Delta Robots

Usage

var five = require("johnny-five");
var Deltabot = require('j5-delta');
var board = new five.Board();
 
board.on("ready", function() {
  var delta = new Deltabot({
    pins: [ 9, 10, 11 ],
    type: 'tapster'
  });
 
  delta.moveTo([20, -20, -150]);
  // other commands 
});

Constructor Parameters

Property Type Value/Description Default Required
pins Array An array of three pins id's with servos attached yes
startAt Number Any number between 0-180. Degrees to initialize the servos at. 5 no
tapDepth Number The depth at which to plunge the end effector for a tap or draw. -160 no
servoSpeed Number Number of seconds it takes your servo to move 60 degrees, used to calculate movement time 0.40 no
dimensions Object Collection of dimensions describing the geometry of the delta robot you want to control. no
type String The name of a known delta robot configuration. If you don't specify this, you should specify dimensions. Valid values: 'tapster', 'junky'

Dimensions

Delta Dimensions

Variable Description
f base length
e end effector length
rf bicep length
re forearm length

If you have a custom delta robot you will need to make a few measurements of the geometry and pass it in. Normally, these measurements should be in millimeters. If your design is open source or commonly available, please consider sending a pull request to add it as a named configuration to configurations.js!

Example initializing with custom dimensions:

var delta = new Deltabot({
    pins: [ 9, 10, 11 ],
    dimensions: {
        f: 163,
        e: 80.25,
        rf: 128.75,
        re: 155
    }
});

API

home()

Move all of the servos to their home position as specififed by startAt at Deltabot initialization.

deltabot.home();

moveTo(coords, [callback])

Move the end effector to the specified X, Y and Z coordinates. Callback is triggered when the movement is done.

deltabot.moveTo([20, -20, -140]);

Note on coordinate system: The coordinate system origin (0,0,0) starts a point directly centered between the three motor axes. Therefore, the Z coordinate of the end effector will always be below that and negative.

getPosition([angles])

Get the current position of the end effector through a forward kinematic calculation. If you do not specify the angles, it will use the last known servo angles.

Note: The position returned by getPosition() will most likely differ from what you passed in to moveTo(). This is due to the limited range of motion on a hobby servo. The position returned by getPosition() is closer to the true position.

deltabot.moveTo([20, -20, -140]);
deltabot.getPosition(); // [ 0, 19.61168100866987, -20.1826220029087, -140.14643590955427 ] 

getServoAngles()

Get the current positions of each of the three servo motors in degrees.

deltabot.moveTo([45, -32, -150]);
deltabot.getServoAngles(); // [ 22, 17, 56 ] 

tap(x, y, [callback])

Tap at the specified X and Y coordinates, plunging to a depth specified by the tapDepth option.

deltabot.tap(40, 75);

draw(coords, [callback])

Draw by dragging the end effector at tapDepth between all of the X,Y coordinates in the coords paramter.

// Draw a 40mm box starting at position 10,10 
deltabot.draw([
  [10,10],
  [50,10],
  [50,50],
  [50,10],
  [10,10]
]);