If you are having trouble calibrating your timer, be sure you have constructed and placed RF shielding correctly.
Each node keeps track of the signal strength (RSSI) on a selected frequency and uses this relative strength to determine whether a transmitter is near the timing gate. The ZippyDecoder timing system allows you to calibrate each node individually so that you can compensate for the behavior and hardware differences across your system and environment.
A node can be Crossing or Clear. If a node is Clear, the system believes a transmitter is not near the timing gate because the RSSI is low. If it is Crossing, the system believes a transmitter is passing by the timing gate because the RSSI is high. A lap pass will be recorded once the Crossing is finished and the system returns to Clear.
The system reports this lap when RSSI drops this amount from the peak RSSI detected in that lap. Smaller values result in the lap being reported immediately exiting the gate. Larger values will result in the quad needing to be farther away before reporting. If too high, a lap may never report..
The RSSI value needed for the system to begin its first pass calibration to detect this quad. To Low, and you risk the system detecting a peak at very low RSSI. Or in rare cases even a neighboring quad to be mistaken.. Too high, and the system will never complete first pass calibration, and will miss laps. Set this to be above the noise floor RSSI.. Note that during the race the actual value used to detect crossings is automatically set based on the peak rssi on first pass, and will likely be a value much larger than this.
Determines how wide of a range of RSSI to consider after the first pass calibration. Smaller gates can use smaller values. Larger gates will need larger values.
Before tuning, power up the timer and keep it running for a few minutes to allow the receiver modules to warm up. The RSSI values tend to increase by a few points as the timer heats up. Common RSSI values: This are typical, but can vary from build to build.. *No quads powered on: 35-45 *Quads powered on but far away: 35-55 *Quads peak during crossing: 90-125
- 20 is a good starting point
- Set value larger than the RSSI value when quads are on the starting blocks.
- 80 is a good starting point.
- Calibration Threshold helps to avoid mistkenly detecting a nearby channel.
- 30 is a good starting point
_Some laps in the race recorded but some did not all. This occurs if the first pass RSSI was very high and Calibration Offset was too low.
- Raise Calibration Threshold
Laps are merged together if Trigger Threshold is too to high, because the lap crossing never completes.
- Lower Trigger Threshold
Extra crossings occur when Calibration Offset is too high.
- Lower Calibration Offset until crossings only begin near the timing gate.
Too many laps occur when Trigger Threshold is too low, because laps are reported too quickly.
- Raise Trigger Threshold
Lap recording takes a long time to complete if Trigger Threshold is high. This does not affect the accuracy of the recorded time.
- Lower Trigger Threshold
Laps will not register if RSSI never reaches Calibration Threshold.
- Lower Calibration Threshold
_Laps will not complete if RSSI never drops low enough to trigger
- Lower Trigger Threshold