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160 Bu il d Y o ur O w n Q u a d c o p t e r

the experiment shown in Chapter 5. Several USB oscilloscope screenshots showed the pulse
waveforms associated with 0, 50, and 100 percent throttle settings. I also discussed all the
remaining AR8000 channels showing that they operated in a similar fashion to the throttle
channel.
A demonstration of how the Propeller BOE could be used to measure pulse width was
shown along with the majority of the program code. The BOE and USB oscilloscope results
were practically identical.
Another BOE program was run to show you how to directly measure pulse frequency.
You determine the pulse rate by calculating the reciprocal of the frequency. A measure of the
pulse frequency or rate is an important number because it ensures that your R/C system is
updating at a fast enough rate. An update that is too slow could lead to loss of control.
The chapter concluded with a detailed discussion of the optional Spektrum telemetry
system. I showed you all of the standard sensors and discussed some of the more advanced
sensors. I also discussed Spektrum’s X-BUS, which in reality, is the standard I C serial bus.
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I mentioned that this bus could be used to add your own sensors and even microcontrollers
onto the telemetry bus.