Thread: Telemetry?
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Old 01-07-2017, 05:27 AM   #29 (permalink)
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Join Date: Aug 2010

Green is telemetry-based pack voltage. Red is what a basic low pass filter many people have tried (and disliked) looks like to your TX alarm logic. Yellow is what a simple, proper filter looks like. You see massive dips in the yellow trace? You see any dips that are not representative of actual pack voltage reduction? That seem too difficult to use as valid telemetry data? There are 2 passive components, retail $0.50 to put together. But why do that, when you can invest in a current integrator, RFID tags, a database to dynamically update your TX model scripts for the pack capacity, and a backup voltage monitoring system (which makes no sense if you already believe the data is invalid…) with its own conditional tests…

Bad telemetry data is worse than useless; it leads to invalid conclusions. And that is the point- telemetry isn’t just about battery state- it is about a lot of things that matter- motor temperature, RX bus voltage, RSSI, etc. But if you implement data capture or processing badly (i.e. assume the motor can represents the coil temperature, or that a 10hz sample rate with a low pass filter on your RX bus will catch 2ms dips…), you end up believing things are great when they may be terrible. Not a lot of value in that.
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