How do you setup a Controller?

Consider I want to setup a gamepad controller to control a simulated robot:

gamepad = ipywidgets.Controller()
gamepad.buttons[0].observe(lambda data: self.robot.device["gripper"].open())
gamepad.buttons[1].observe(lambda data: self.robot.device["gripper"].close())
gamepad.axes[1].observe(lambda data: self.robot.move(-data["new"], 0), 'value')

But I can’t do that (I guess) because the gamepad hasn’t been initialized yet. When should I hook up the buttons to the functions? Is there a callback for after the controller has been initialized?

BTW, here is the simulator: https://github.com/Calysto/jyro/blob/master/docs/Jyro Simulator.ipynb

[SylvainCorlay]

The flight simulator example does:

pad.links = []

def setup():
    if pad.connected:
        pad.links.append(dlink((pad.axes[1], 'value'), (fly_controls, 'pitch'), affine(0.0, factor)))
        pad.links.append(dlink((pad.axes[0], 'value'), (fly_controls, 'roll'), affine(0.0, -factor)))
        pad.links.append(dlink((pad.axes[3], 'value'), (fly_controls, 'forward_speed'), affine(0.0, 2 * factor)))
        pad.links.append(dlink((pad.axes[2], 'value'), (fly_controls, 'yaw'), affine(0.0, factor)))
        pad.links.append(dlink((pad.buttons[5], 'value'), (surf, 'scale'), lambda x: (10, 10, 1 - x)))
    if not pad.connected:
        for l in pad.links:
            l.unlink()
        pad.links = []

pad.observe(setup, names=['connected'])
setup()

[jasongrout]

Oh, I forgot about the .connected observable attribute. I’d rather just observe that, like you did above, without adding another function. That way we’re consistent in how to trigger actions - just use observe.