Table of Contents

Control LEDs

The Behavior board drives two kinds of light output: two standard current-controlled LEDs on the L0 and L1 connectors and up to two WS2812-type addressable RGB LEDs on the RGB connector. Refer to the connections article to set up the LED on L0 or the RGB connector, which we will use for the rest of these examples.

This article covers configuring LED drive current, setting RGB colors, and turning on both kinds of LED output in Bonsai.

The complete workflow is shown below. Copy and paste it into Bonsai or build each section by following the step-by-step instructions below.

Control LEDs

Configure LED Current

The L0 and L1 outputs drive standard single-color LEDs with a configurable constant current, so no series resistor is needed. Each output has a working current and protection limit register (e.g. Led0Current and Led0MaxCurrent for L0). Writes above the limit are rejected by the device.

Configure LED Current

  • Insert a KeyDown operator and set the Filter property to A.
  • Insert a CreateMessage operator and configure the following properties:
    • Payload - Select Led0MaxCurrentPayload.
    • Led0MaxCurrent - Set the maximum allowed current according to the rating of the LED in mA (e.g. 20). Valid values are 2–100 mA.
  • Insert a MulticastSubject operator named Behavior Commands.
  • Insert a CreateMessage operator and configure the following properties:
    • Payload - Select Led0CurrentPayload.
    • Led0Current - Set the working current in mA (e.g. 10). Valid values are 5–100 mA.
  • Insert a MulticastSubject operator named Behavior Commands.

Run the workflow and press A to configure the L0 drive current, then switch the output on as shown in the next section.

Turn LEDs On and Off

Once the drive current is configured, the L0 and L1 outputs are switched like any other digital output, for instance through the OutputSet and OutputClear registers:

Turn LEDs On and Off

  • Insert a KeyDown operator and set the Filter property to S.
  • Insert a CreateMessage operator and configure the following properties:
    • Payload - Select OutputSetPayload.
    • OutputSet - Select the line to turn on (e.g. Led0).
  • Insert a MulticastSubject operator named Behavior Commands.

In a separate branch:

  • Insert a KeyDown operator and set the Filter property to D.
  • Insert a CreateMessage operator and configure the following properties:
    • Payload - Select OutputClearPayload.
    • OutputClear - Select the line to turn off (e.g. Led0).
  • Insert a MulticastSubject operator named Behavior Commands.

Run the workflow, then press S to turn on the LED and D to turn it off. See Control Digital Outputs for other methods to control the LED.

Set RGB Colors

The RGB connector drives WS2812-type individually addressable LEDs. The two LEDs form a serial chain on a single data line: Rgb0 is the first LED in the chain and Rgb1 the second when configuring and controlling these LEDs. Single-color LEDs have no data input and do not work on this connector; drive those from the L0/L1 outputs instead. Analog RGB LEDs are not supported on either.

The RgbAll register writes the color of both RGB LEDs in one command. Each channel takes an intensity from 0 to 255.

Set RGB Colors

  • Insert a KeyDown operator and set the Filter property to F.
  • Insert a CreateMessage operator and configure the following properties:
    • Payload - Select RgbAllPayload.
    • Red0 - Set the value for the red channel on Rgb0 (e.g. 255).
    • Blue1 - Set the value for the blue channel on Rgb1 (e.g. 255).
  • Insert a MulticastSubject operator named Behavior Commands.

Run the workflow and press F to load the colors. If the LEDs are currently on, the new colors take effect immediately. If not, when you turn them on in the next section, , Rgb0 should display red and Rgb1 should be blue.

Note

To configure one LED at a time, use the Rgb0 or Rgb1 registers instead.

Note

There is a bug in the current firmware (v3.3) where the red and green channels are switched (e.g. Red0 controls the LED green channel instead). As a workaround, swap the two channel values to get the intended color.

Turn RGB LEDs On and Off

The RGB LEDs are switched like any other digital output, for instance through the OutputSet and OutputClear registers:

Turn RGB LEDs On and Off

  • Insert a KeyDown operator and set the Filter property to G.
  • Insert a CreateMessage operator and configure the following properties:
    • Payload - Select OutputSetPayload.
    • OutputSet - Set the lines to turn on (e.g. Rgb0, Rgb1).
  • Insert a MulticastSubject operator named Behavior Commands.

In a separate branch:

  • Insert a KeyDown operator and set the Filter property to H.
  • Insert a CreateMessage operator and configure the following properties:
    • Payload - Select OutputClearPayload.
    • OutputClear - Set the lines to turn off (e.g. Rgb0, Rgb1).
  • Insert a MulticastSubject operator named Behavior Commands.

Run the workflow, then press G to turn on both RGB LEDs and H to turn them off.


Last updated with:
Hardware v2.1
Firmware v3.3
Bonsai Package v0.2

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