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108 Bu il d Y o ur O w n Q u a d c o p t e r
Figure 5.19 Complete test setup.
a distance of 4 to 6 in. A sensitive photo cell at the top of the unit detects light reflections from
the propeller. Notice that the unit is showing 3600 r/min in the figure, which is due to the
flicker rate of the lights used in the photography setup. Pressing the button on the front of
the unit a second time will switch it from a two-bladed to a three-bladed measurement
mode—definitely a handy tool to possess.
Running the Experiment
Before the experiment can start, the demo program mentioned above must be loaded into
the BOE’s EEPROM. The test circuit must also be connected, as shown in Figure 5.17, with
Figure 5.20 Optical tachometer.
