Thymio

Contents

Thymio#

If you have a Thymio, you can interact with it using pyaseba.

Client#

The lower-level interface is offered by pyaseba.Client and its asynchronous counterpart pyaseba.ClientAsync.

The first step is to connect the serial port and wait until we discover the robot.

$ python

>>> from pyaseba import Client
>>> client = Client()
>>> client.connect("ser:name=Thymio")
1
>>> node_id, conn = client.wait_node(wait_ms=5000)
>>> node_id, conn
(48069, 1)

A positive node_id means that we discovered the Aseba node running on the robot. We can use it to get/set variables.

>>> list(client.get_description(node_id).variables)
['_fwversion', '_id', '_imot', ...
>>> client.get_variable(node_id, "temperature")
[250]
>>> client.set_variable(node_id, "leds.top", [32, 0, 0])

The robot should have turned red.

We can load an Aseba script and ask the robot to run it.

>>> script = """
... onevent button.center
... leds.top = [0, 32, 0]
... if button.center == 1 then
...   emit pressed
... end
...
... onevent reset
... leds.top = [0, 0, 0]
... """
>>> client.load_script(node_id, script, events={'reset': 0, 'pressed': 0})
>>> client.cmd_run(node_id)

The robot should turn green when you press the central button.

We can now send an event from Python, which in this case, should make the robot switch off the LED;

>>> client.emit_event(node_id, "reset")

wait until an event is emitted (press the button after executing the code);

>>> client.get_event(node_id, "pressed", wait_ms=10000)
Event(source=48069, name='pressed', data=[])

and trigger a callback when this happens.

>>> def cb(event):
...     print(event.name)
...
>>> client.add_event_callback(cb)

Try pressing the button again and you should see the pressed logged on your console.

Node#

The higher-level pyaseba.client.Node offers a simplified interface to interact with a single Aseba node, in this case running on the robot.

We go through similar steps as with the client: first, connect the robot:

$ python

>>> from pyaseba.client.thymio import Thymio
>>> thymio = Thymio()
>>> thymio.connect(start_mirroring=True)
True

We can get and set variables by name,

>>> list(thymio.description.variables)
['_fwversion', '_id', '_imot', ...
>>> thymio.get("temperature")
284
>>> thymio.set("leds.top", [32, 0, 0])

or using Python attributes.

>>> thymio.temperature
284
>>> thymio.leds_top = [0, 0, 32]
>>> thymio.sync()

The robot should have turned first red and then blue.

Note

The thymio object caches variable values. The pyaseba.client.Node.sync() forwards to the robot any variable we have changed locally. When calling pyaseba.client.Node.get() and pyaseba.client.Node.set(), we can specify if we want to query/forward variables or if we prefer to get/set them from the cache. Instead, attributes like thymio.leds_top always use the cache.

To set other LEDs, we can call local functions by name, like

>>> thymio.call("leds.circle", 0, 32, 0, 32, 0, 32, 0, 32)

or, using specific methods

>>> thymio.call_leds_circle(0, 32, 0, 32, 0, 32, 0, 32)

We can wait for local events, like a button press. Try pressing the button after running the line below

>>> thymio.wait("button.center")

The following Python callback implements the same logic as the Aseba script of the previous example.

>>> def cb(thymio):
...     if thymio.button_center:
...         print('pressed')
...     thymio.call_leds_top(0, 32, 0)

We can assign it to the local event by name

>>> thymio.set_callback("button.center", cb)

or using specific methods

>>> thymio.on_button_center = cb

As before, the robot should turn green when you press the central button and you should get a pressed printed on your console.

Contents