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3.3.0 Adjusting the Capacitive-Touch Sensitivity
The “INTESNITY” knob of the front panel of the treadmill controller no longer applies an electrical
stimulus to the grids, but now selects the sensitivity of the capacitive-touch sensors monitoring the grids.
Like all capacitive touch sensors, they monitor for a relative quick increase in measured capacitance as
indication of the presence of the animal. A baseline measurement of the initial capacitances of all grids are
sampled upon power-up. Subsequently, small adjustments are made periodically to the baseline as the
measured capacitance slowly drifts over time and temperature. When any grid indicates the presence of an
animal for a duration of two (2) minutes, that grid will be re-baselined, which will remove the presence
condition. Should this occur because of the actual presence of the animal, detection from that grid will stop
until the periodic adjustments correct it which will take an indeterminate amount of time. Therefore, it is
important to adjust the air-stimulus pressure and repetition rate to ensure that the animals do not stay on the
grids for longer than two (2) minutes.
Use the following procedure to empirically determine the “INTENSITY” setting.
1. Switch “ON” the Treadmill Controller and Treadmill Stimulus Detection interfaces. Also connect the
12-volt supply to the Exer 3/6 Treadmill.
2. On the Treadmill Controller, select a typical “SPEED” employed in the experiment and set the
“TREADMILL BELT” switch to “RUN”. Also, set the “REP RATE” to “3Hz” and the
“INTENSITY” to zero.
3. On the Treadmill Stimulus Detection, begin a manual experiment with high numbers for the “NOV”
and “NOS” (to allow the stimulus signal from the Treadmill Controller to pass through to the Exer 3/6
Treadmill).
4. On the Exer 3/6 Treadmill, enable the stimulus for all lanes using the toggle switches. At the lowest
intensity (sensitivity), random presence detections are typical and persistent. The action of the valves
will bleed the air-pressure from the reservoir and system.
5. On the Treadmill Controller, slowly increase the “INTENSITY” setting at a rate of 10 divisions per
second until the action of the valves cease.
6. Momentarily touch each grid to trigger that lane’s valve. If the valve’s action persists, return to step 5.
If the valve action stops and all the grids have been checked, then the minimum sensitivity has been
found. Increase the setting by 20 divisions.
Each Treadmill Controller’s settings will be slightly different due to tolerance and manufacturing.
Likewise, if you observe any false detections, increase the setting by 10 divisions. Likewise, if you observe
any unaccounted detections, decrease the setting by 10 divisions.
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