User manual

Height
The unit includes a Bosch BMP180 integrated digital
pressure and temperature sensor. Since this is used
to report altitude, the reading will vary with local
barometric pressure. Accordingly, in order to display
height above ground level (AGL), which is what most
people are looking for when they think of the height
of a model, the Hyperion telemetry unit as delivered
sets the altitude reading to zero every time power is
connected. The Hyperion altimeter is quite accurate
by hobby standards. It is ambient temperature
compensated but will have small errors due to
internal noise, onboard heating of the components,
and natural variation of atmospheric pressure during the flight. It is normal for the height reading to
fluctuate by up to 6ft/2m, and this variation may increase during
unusual weather conditions with rapidly changing conditions. This is an inherent behavior of a
pressure altimeter and not a fault of the unit. Display in meters or feet is chosen in the telemetry
setup screen. Flight battery current is displayed on the same screen if you have the V/I sensor
connected.
Temperature
The external temperature probe is accurate at room temperature to within 1°F or better. The sensing
element is a 10kNTC thermistor, and maintains good accuracy at all temperatures. The internal
temperature reported by the unit when no external temperature sensor is plugged in may be a little
higher due to heat dissipation on the board. The
reading can be displayed in °C or °F but is limited to
whole degree resolution in both.
RPM
The RPM input is obtained via a single wire connected
to any of the three wires of a brushless motor. The unit
detects voltage pulses from the motor wire and
calculates RPM from their frequency, based on the
setting on the transmitter telemetry setup screen for the
number of magnetic poles in the motor. The display shows 1/10 of the actual RPM. That is, 1234 is
actually 12,340 rpm.
If the number of poles is not available, it can be
estimated by comparing RPM displayed with the reading
from an optical tachometer while the motor is running;
the pole number can be adjusted to get agreement.
Hyperion suggests that the gear ratio adjustment
provided on the Spektrum™ transmitter can also be used
to match the RPM display to the tachometer reading.
It should be noted that the RPM circuit is just a simple
voltage divider with some software filtering and an
adjustment for waveform that is not always reliable or