Nest

The nest module is utilised with a nest hardware module assembly (consisting of a weighing scale) to provide shelter for animals in the habitat and a means to track and measure their weight.

Nodes

WeightScale

The WeightScale (Aeon.Environment) node establishes a serial connection to the weighing scale in the nest, allowing direct control to read the weight, as well as to send tare commands to the scale. The node also processes the weight data from the scale to calculate a baseline weight that can be subtracted on a trigger. It also filters the weight signal with a linear regression filter over a sliding window defined in its properties. Finally, a measure of confidence for each of these readings is calculated.

These measures are packaged into Aeon.Environment.WeightMeasurement class, each composed of the “Timestamp” (double), “Value” (float) and the “Confidence” index (float) of the weight measure.

Inputs

None

Outputs

Stream of DynamicClass with the following attributes:

Attribute name	Type	Description
RawWeight.Value	float	Raw weight measurement value from the scale
RawWeight.Confidence	float	Confidence score for the raw weight measurement
RawWeight.Timestamp	double	Timestamp when the raw weight measurement was recorded
FilteredWeight.Value	float	Filtered weight measurement after smoothing/filtering
FilteredWeight.Confidence	float	Confidence score for the filtered weight
FilteredWeight.Timestamp	double	Timestamp when the filtered weight measurement was recorded
BaselinedWeight.Value	float	Baseline-adjusted weight measurement
BaselinedWeight.Confidence	float	Confidence score for the baselined weight
BaselinedWeight.Timestamp	double	Timestamp for the baselined weight measurement

Properties

General

Property name	Description
PortName	Name of the serial port used to communicate with the digital scale
FilterWindow	Defines the size of the sliding window for linear regression filtering of weight measurements

Subjects

Events and commands from the weighing scale are collected from, and published to Subjects, in some cases after some processing. Here you set the names used for these Subjects to identify events, commands or data streams for this node for a specific nest. Each of these subjects becomes accessible in the Bonsai editor’s toolbox anywhere in the workflow using the name set here.

Device event subjects

Subject name	Type	Description
WeightData	Aeon.Environment.WeightMeasurement	Contains timestamped weight measurements both raw and after filtering and baseline adjustments. Also directly output by the node
TareEvents	Harp.Timestamped	Timestamped tare events indicating tare commands sent to the scale

Other output subjects

Subject name	Type	Description
RawWeight	Aeon.Environment.WeightMeasurement	Raw weight data directly from the serial input
FilteredWeight	Aeon.Environment.WeightMeasurement	Filtered weight data based on the configured filter window size
BaselinedWeight	Aeon.Environment.WeightMeasurement	Baseline-adjusted weight data

Device command subjects

Subject name	Type	Description
TareCommands	object	Input sequence for tare commands, sent to reset the scale’s weight measurement
GlobalTrigger	object	A global trigger that synchronizes with external events or reset triggers for baseline weight.
BaselineWeightTrigger	object	Specifies the trigger for resetting the baseline weight

Usage

Create a Groupworkflow and give it an appropriate name, e.g. “Nest”. Inside, place a WeightScale (Aeon.Environment) node, externalise all properties, and connect to the WorkflowOutput.

GUI

No specific GUI components are defined for this module.

Logging

Outputs from the nest module are collected and formatted into Harp messages using the Harp.Format and custom FormatWeight nodes to configure the register addresses for each data stream on a virtual Harp device, utilising commonly available registers. Logging of this virtual Harp device can then be performed as with any Harp device using the LogHarpState (Aeon.Acquisition) node.

Data schema

Register name	Access	Address	Type	Mask type	Description
(weight_raw)	Event	200	[double,float,float]	[Timestamp,Value,Confidence]	Logs raw weight data directly from the scale input
(weight_tare)	Write	201	U8	-	Logs each tare command event with a timestamp
(weight_filtered)	Event	202	[double,float,float]	[Timestamp,Value,Confidence]	Logs weight data after filtering adjustments
(weight_baseline)	Write	203	U8	-	Logs events with a timestamp when the baseline weight is reset

State persistence

Weight measurements are not required for environment state persistence.

Alerts

Alerts are not currently configured for weight measurements, but could be configured to alert the team to, for example, drops in measured weight below a threshold for a given animal.