Table of Contents

Acquire Analog Data

The Behavior board has up to two analog inputs: AD0 is located on the ADC connector and AD1 is located on the Input connector (hardware v2.0 and later boards). The analog input can be tested with an analog output from a photodiode. Refer to the connections article to set up the hardware connection on AD0, which we will use for the rest of these examples.

This article covers how to visualize the timestamped analog input stream and extract a single channel with its timestamp 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.

Acquire Analog Data

Visualize Analog Data

Both analog inputs accept voltages from 0 to 5 V, which are subsequently digitized by an onboard 12-bit analog-to-digital converter (ADC) and broadcast as an AnalogData event stream at 1 kHz. The workflow below will show you how to filter, decode and visualize the AnalogData events:

Analog Data Visualize

To visualize only one of the input channels:

  • Insert a MemberSelector operator on a separate branch to select specific fields from the bundled analog data payload.
  • Double-click the MemberSelector operator to open the editor, and add the Value.AnalogInput0 and Seconds members to the selection. This will select the individual channel data as well as the timestamp.
  • Insert a VisualizerWindow operator. This will open a second window displaying only the selected channel and its timestamp.

Run the workflow, the first visualizer displays the three payload values followed by the timestamp in seconds:

AnalogDataPayload { AnalogInput0 = 13, Encoder = 0, AnalogInput1 = 13 }@10.351072
AnalogDataPayload { AnalogInput0 = 15, Encoder = 0, AnalogInput1 = 14 }@10.352072

and the second displays the AnalogInput0 value paired with its timestamp.

(13, 10.351072)
(15, 10.352072)

If you are using a photodiode, shine a light on the photodiode to see the analog input value change. If you are using a different signal source, vary the output voltage instead.

Note

The Encoder value bundled together in the payload is not an analog voltage reading but a quadrature encoder counter that is sampled on the same 1 kHz tick so that position and analog data share the same timestamps.

Note

The analog events are enabled by default, but if nothing appears, they may have been disabled by another configuration setting. Refer to the link to find out how to re-enable them.


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

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