Ham Radio in STEM Education The Montgomery College Satellite Antenna Rotator Project Daniel Albuquerque, Raymond Botty, KK4HDR, Jordan Deuser, Kyle Nathan, Dennis Ngo presented by David Bern, W2LNX, adviser Montgomery College, Rockville, Maryland David.Bern @ MontgomeryCollege.edu W2LNX @ AMSAT.org 2013 AMSAT Space Symposium 1 of 27 November 1-3, 2013 - Houston, TX
27
Embed
The Montgomery College Satellite Antenna Rotator Projectmstl.atl.calpoly.edu/.../Bern_Montgomery_College_Rotator.pdf · The Montgomery College Satellite Antenna Rotator Project ...
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Ham Radio in STEM Education
The Montgomery College Satellite Antenna
Rotator Project
Daniel Albuquerque, Raymond Botty, KK4HDR, Jordan
Deuser, Kyle Nathan, Dennis Ngo
presented by David Bern, W2LNX, adviser
Montgomery College, Rockville, Maryland
David.Bern @ MontgomeryCollege.edu
W2LNX @ AMSAT.org
2013 AMSAT Space Symposium 1 of 27 November 1-3, 2013 - Houston, TX
Introduction
agenda – using ham radio in STEM education
● desire to
● play with Raspberry Pis – a solution looking for a
problem
● organize a hacker/maker/DIY/robotics/ham radio club
summer student workshop at Montgomery College
● At the AMSAT-DC Spring 2013 Workshop
● Tom K3IO, suggested to use DiSEqC antenna rotators
as inexpensive azimuth and elevation rotator system
● a problem to solve with a Raspberry Pi?
2013 AMSAT Space Symposium 2 of 27 November 1-3, 2013 - Houston, TX
DiSEqC rotator
Eagle Aspen Pro Brand International rotator
● runs on 13 V DC, 450 degrees
2013 AMSAT Space Symposium 3 of 27 November 1-3, 2013 - Houston, TX
Raspberry Pi computer
● software – Raspbian Linux with Python, C/C++ installed
● hardware – GPIO pins, Ethernet and USB ports
2013 AMSAT Space Symposium 4 of 27 November 1-3, 2013 - Houston, TX
DiSEqC protocol
Eutelsat Digital Satellite Equipment Control – DiSEqC
● DiSEqC signal and power on same wire
● 22±4 KHz pulse train 650±250 mV peak-to-peak
● one-third bit Pulse Width Keying (PWK)
● 0 bit: 1.0 ms followed by 0.5 ms silence
● 1 bit: 0.5 ms followed by 1.0 ms silence
● 6 ms between DiSEqC commands
2013 AMSAT Space Symposium 5 of 27 November 1-3, 2013 - Houston, TX
DiSEqC protocol
DiSEqC signal from Eagle Aspen controller
DiSEqC signal to TTL level converter circuit
2013 AMSAT Space Symposium 6 of 27 November 1-3, 2013 - Houston, TX
DiSEqC protocol
●DiSEqC commands bytes
● unidirectional to Eagle Aspen rotator
● does not use parity bit
● five command bytes to set position
● example: GO TO 255.0 DEGREES – E0 31 6E 0F F0
● E0 – framing byte: command from master, no reply
required
● 31 – address byte: polar/azimuth positioner
● 6E – drive motor to angular position (°)
● 0F F0 – 255 x 16
2013 AMSAT Space Symposium 7 of 27 November 1-3, 2013 - Houston, TX
2013 AMSAT Space Symposium 17 of 27 November 1-3, 2013 - Houston, TX
diseqc_rotator_control.py
import RPi.GPIO as GPIO import time import sys import os from configuration import * from Eagle_Aspen_rotator import Eagle_Aspen_rotator from routines import *