Page 139 - Build Your Own Quadcopter_ Power Up Your Designs with the Parallax Elev-8

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

‘ Modified to drive a Brushless Motor using an ESC/BEC motor
controller.
‘ Note a BEC type ESC supplies 5V on the center servo pin (some
servos are different).
‘ Therefore, only two wires should be connected, being ground and
servo pin.
“ I have used the TV output because it has a series resistor for
protection and ground outputs. I have connected an RCA plug to a
servo type cable & plug from an old PC and a 3pin stake block. You
could also put a series resistor in the RCA plug for protection if
you wish.”

“ Here is the connection diagram...
NOTE: Deleted from this copy, see original if needed”
‘─────────────────────────────────────────────────’
‘ Uses the PropPlug and PSerialT to set the motor speed from the
PC Keyboard
‘ 0=OFF, 1=12.5%, 2=25%, 3=37.5%, 4=50%, 5=62.5%, 6=75%,
7=87.5%, 8=ON
‘─────────────────────────────────────────────────
“ RR20100426 _rr001 use 20ms and 1ms...2ms (motor 1ms=off,
1.5ms=50%, 2ms=100%)”
“ uses fdx and PSerialT: 0=OFF, 1=12.5%, 2=25%, 3=37.5%, 4=50%,
5=62.5%, 6=75%,7=87.5%, 8=ON”

CON
_xinfreq = 5_000_000
_clkmode = xtal1+pll16x ‘The system clock is set at 80MHz
(rec’d for optimal res)
Servo_Pin = 14 ‘ use the TV pin (My note: servo
pin 14)
rxPin = 31 ‘ serial
txPin = 30
baud = 115200
tvPin = 14 ‘TV pin (1-pin version)
kdPin = 26 ‘Kbd pin (1-pin version)

OBJ
fdx : “FullDuplexSerial” ‘serial driver

VAR
long position ‘The assembly program will read this variable
from the main Hub RAM to determine the servo
signal’s high pulse duration

PUB Demo | ch