===== Main code =====

 This is in python, you can find a detailed guide on installing python on the NGW100 [[http://www.cibomahto.com/?p=82|here]]. The reed_solomon library can be found on the wiki [[code:python_reedsolomon|here]]


<code python>
#!/media/mmcblk0p1/install/bin/python
##!/usr/bin/python

 
import reed_solomon
import serial
import math
import time
import os
TRUE=1
FALSE=0
DEG2RAD=math.pi/180.0
class updatest:
	pass
mynumber="44<really think I'd be that silly?>"
default_target_pressure=40
limit=[200,10000,20000]                #our altitude ranges for the different samples
max_flight_time=7000
callsign="AOPP"
logname="flightlog.txt"
Roottwotwomgovercda = (2*9.81*2/0.72)**0.5 #work this out for our payload mass, cda from http://members.aol.com/nakkarocketry/paratest.html
iterations=0
Jxpoints=[]
Jypoints=[]
updatestuff=updatest()
 
 
 
def gps_status():
	print 'Retrieving GPS status'
	gpspos_parts=['']	
	while not gpspos_parts[0]=='$GPGGA':
		gpspos=ser_gr.readline()
		print "got" , gpspos
		gpspos_parts = gpspos.split(',')
	if ((gpspos_parts[6]=='1') or (gpspos_parts[6]=='2') or (gpspos_parts[6]=='3')): #2D or 3D fix/DGPS fix
		print 'GPS fix' , gpspos_parts[6] , 'ie valid'
		status=TRUE
	else:
		print 'GPS fix' , gpspos_parts[6] , 'ie not valid'
		status=FALSE
	return status
 
def gps_data():
	ser_gr.flushInput()                       #as gps strings will have built up over time
	print 'Retrieving GPS data'
	gpspos_parts=['']	
	while not gpspos_parts[0]=='$GPGGA':
		gpspos=ser_gr.readline()
		gpspos_parts = gpspos.split(',')
	gpstime=3600*float(gpspos_parts[1][0:2])+60*float(gpspos_parts[1][2:4])+float(gpspos_parts[1][4:])
	latitude=float(gpspos_parts[2][0:2])+float(gpspos_parts[2][2:])/60.0 
	if gpspos_parts[3]=="S":
		latitude=-latitude
	longitude=float(gpspos_parts[4][0:3])+float(gpspos_parts[4][3:])/60.0
	if gpspos_parts[5]=="W":
		longitude=-longitude
	if gpspos_parts[9]=='':
		gpspos_parts[9]='0.0'
	altitude=float(gpspos_parts[9])
	#print gpstime,latitude,longitude,altitude
	return gpstime,latitude,longitude,altitude
 
def db_stats():
	ser_daughter.flushInput()         #we done want to mess things up with old data in the buffer
	ser_daughter.write("V1\r\n")      #the high voltage values
	V1=ser_daughter.readline()
	ser_daughter.write("V2\r\n")
	V2=ser_daughter.readline()	
	ser_daughter.write("V3\r\n")
	V3=ser_daughter.readline()
	ser_daughter.write("I\r\n")        #the total ioniser current
	IC=ser_daughter.readline()
	#ser_daughter.write("B\r\n")        #battery voltage
	#VB=ser_daughter.readline()
	ser_daughter.write("D\r\n")        #pressure difference
	PD=ser_daughter.readline()
	ser_daughter.write("T\r\n")        #new - temperature sensor, to be fitted
	TS=ser_daughter.readline()
	return V1[:len(V1)-2],V2[:len(V2)-2],V3[:len(V3)-2],IC[:len(IC)-2],PD[:len(PD)-2],TS[:len(TS)-2]
 
def HV_enable(n):
	stringy='H'+str(n)+"\r\n"
	ser_daughter.write(stringy)
	print ser_daughter.readline()
 
def Set_pressure_target(P):
	ser_daughter.write('P'+str(P)+"\r\n")
 
def air_density(alt):    # NASA air temperature/pressure/density model
	if (alt < 11000.0):
         # below 11Km - Troposphere
		temp = 15.04 - (0.00649 * alt)
		pres = 101.29 *(((temp + 273.1) / 288.08)**5.256) 
	else:
		if (alt < 25000.0):
         # between 11Km and 25Km - lower Stratosphere
			temp = -56.46
			pres = 22.65 * math.exp(1.73 - ( 0.000157 * alt))
		else:
         # above 25Km - upper Stratosphere
			temp = -131.21 + (0.00299 * alt)
			pres = 2.488 *(((temp + 273.1) / 216.6)**-11.388)
	return(pres / (0.2869 * (temp + 273.1)))
 
 
def Updatepredict(Seconds,North,East,Altitude):
	Deltae=East-updatestuff.Oldeast
	Deltan=North-updatestuff.Oldnorth
	Deltaa=Altitude-updatestuff.Oldaltitude
	Deltat=Seconds-updatestuff.Oldseconds
	Averagealt=(updatestuff.Oldaltitude+Altitude)/2
	if Deltaa>0:
		K=Roottwotwomgovercda*(air_density(Averagealt)**-0.5)  #we now have the velocity of decent
		print "Descent velocity=",K
		K=Deltaa/K                                            #time of decent for this layer
		print "descent time=",K
		K=K/Deltat                                            #weighting for this layer
		print "Layer weighting=",K
		updatestuff.Predictedn+=(K+1)*Deltan                #need to account for ascent drift
		updatestuff.Predictede+=Deltae*( (K*math.cos(((North + updatestuff.Oldnorth)/2)*DEG2RAD)/math.cos(updatestuff.Predictedn*DEG2RAD)) +1)
	updatestuff.Oldeast=East
	updatestuff.Oldnorth=North
	updatestuff.Oldaltitude=Altitude
	updatestuff.Oldseconds=Seconds
	print "predicted north=",updatestuff.Predictedn
	print "predicted east=",updatestuff.Predictede
	return updatestuff.Predictedn,updatestuff.Predictede
 
 
def are_we_inside(gpstime,Xpos,Ypos,altitude):
	count=False
	print "checking",Xpos,Ypos
	for g in range(len(Jxpoints)):
		if g==len(Jxpoints)-1:
			gplus=0
		else:
			gplus=g+1
		if ((Jypoints[g]>Ypos and Jypoints[gplus]<Ypos) or (Jypoints[g]<Ypos and Jypoints[gplus]>Ypos))and(((Jxpoints[g]-Xpos)+((Ypos-Jypoints[g])*(Jxpoints[gplus]-Jxpoints[g])/(Jypoints[gplus]-Jypoints[g])))>0):
			count=not count
			print "intercept",g
	print 'we are inside=',count
	return count
 
def load_kml(filepath):
	xpoints=[]
	ypoints=[]
	found=False	
	for line in open(filepath,'r').readlines():
		if not line.find("<coordinates>")==-1:
			found=True
		if not line.find("</coordinates>")==-1:
			found=False		
		if found:
			line_split=line.split(',')
			if len(line_split)==3:			
				xpoints+=[float(line_split[0])]
				ypoints+=[float(line_split[1])]
	return xpoints,ypoints
 
def send_sms(s,target):
	target=str(target)
	if not len(target)==12:
		print "phone number incorrect lenght"
		return -1
	if len(s)>160:
		print "text is too long"
		return -1
	E=0
	D=1
        stringy=""
	t=""
	Bitstring=[0]
	for G in s:
		Numb=ord(G)
   		for M in range(7):
			if (Numb >> M) & 1:
				Bitstring[E]+=D
			D*=2
    			if D==256:
				D=1
				E=E+1
				Bitstring.append(0)
	print "SMS"
	stringy="AT+CMGS="+str(14+(int(len(s)*7/8)+1))+"\r\n" #total lenght
	#print stringy
	ser_phone.write(stringy)
	print ser_phone.readline()       #echo the command
	ser_phone.readline()
	print ser_phone.readline()       # the "> " is recieved
	stringy="0011000C91"               # SMS submit, 12 digit international
	for g in range(6):
		stringy+=(target[2*g+1])
		stringy+=(target[2*g])
	stringy+="0000AA"             #PDU string to Mobile, 4 day validity
	stringy+="%.2X" % len(s)      #datalenght
	for G in Bitstring:
		stringy+="%.2X" % G   #a load of HEX
	stringy+=chr(26)             #send it
	ser_phone.write(stringy)
	for n in range(4):
	 print ser_phone.readline()
#	print stringy
	return 0
 
def get_smscen():
	ser_phone.write("AT+CSCA?\r\n")
	ser_phone.readline()
	s=ser_phone.readline()
	s=s.split('"')
	return str(s[1:2])[3:15]
 
def cutdown():
	ser_gr.write("Cutdown...   ")
	shutdown()
	os.system("echo 0 > /config/gpio/cuttertwo/enabled")      #payload release
	time.sleep(6)
	os.system("echo 1 > /config/gpio/cuttertwo/enabled")      #and we are on the way down
	print "released"
 
def shutdown():
	HV_enable(0)             #all off
	Set_pressure_target(0)	 #pump off
	time.sleep(1)            #wait, to avoid smoke contamination
	os.system("echo 0 > /config/gpio/cutterone/enabled")      #cut plunger 
	time.sleep(3)
	os.system("echo 1 > /config/gpio/cutterone/enabled")	
	print "plunger cut"
	ser_gr.write("Shutdown\r\n")
 
try:
	print 'AOPP aerosol experiment running'
	#log=open("/media/mmcblk0p1/"+logname,"a+")
	log=open("./"+logname,"a+")
	ser_gr=serial.Serial('/dev/ttyS2',4800, timeout=2, rtscts=1)    #we have a CTS line from the radio
	#ser_gr=open("radio.txt","r")
	ser_daughter=serial.Serial('/dev/ttyS1',19200, timeout=2)
	#ser_daughter=open("daughter.txt","a+")	
	ser_phone=serial.Serial('/dev/ttyS0',9600,timeout=4)
	#ser_phone=open("phone.txt","a+")
	print 'serial is open to gps,radio, and daughterboard'
	ser_gr.write("Hello world")
	#log.write("Hello world")
	reed_solomon.setup_rs()
	ser_gr.write(reed_solomon.encode_string("Hello, I am a reed solomon encoded string :P"))
	#log.write(reed_solomon.encode_string("Hello, I am a reed solomon encoded string :P"))
#	while not gps_status():
#		ser_gr.write("waiting for the gps to lock")
		#log.write("waiting for the gps to lock")
	print 'ok, gps is ready, we are at:'
	ser_gr.write("GPS locked")
	#log.write("GPS locked")
	print gps_data()
	print 'now probing daughterboard'
	print db_stats()
	print 'DANGER: turning on HV1'
	HV_enable(1)
	print 'HV1 on, probing board'
	time.sleep(1)
	print db_stats()
	print 'testing other HV channels'
	for x in [2,3]:
		HV_enable(x)
		time.sleep(1)
		print 'HV channel' + str(x) + 'stats:' + str(db_stats())
	HV_enable(0)
	print 'ok, now testing the pump @ 20%'
	Set_pressure_target(20)
	for i in range(20):
		print db_stats()
		time.sleep(1)
	Set_pressure_target(0)
	print 'pressure set to zero'
	for i in range(6):
		print db_stats()
		time.sleep(1)
	print 'Testing done'
	print 'opening KML cutdown file'
	Jxpoints,Jypoints=load_kml('./cutdown.kml')
	print Jxpoints,Jypoints
	print 'testing phone'
	ser_phone.write("AT\r\n")
	print ser_phone.readline()
	print ser_phone.readline()
	#smscen=get_smscen()
	send_sms("hello world",mynumber)
	ser_daughter.flushInput()
	ser_phone.flushInput()
	system_vector=gps_data()
	updatestuff.Predictedn=system_vector[1]
	updatestuff.Predictede=system_vector[2]
	updatestuff.Oldeast=system_vector[2]                                            #start
	updatestuff.Oldnorth=system_vector[1]
	updatestuff.Oldaltitude=system_vector[3]
	updatestuff.Oldseconds=system_vector[0]
	count=0
	calibrate=0
	layercounter=0
	cut_down=''
	system_vector=gps_data()
	maxaltitude=system_vector[3]
	startuptime=system_vector[0]
	HV=0
	pump=FALSE
	print 'ok launch the balloon'
	while 1:
		print 'in loop'
		system_vector=gps_data()
		daughter_board=db_stats()
		datastring = ','.join(['%.0f' % system_vector[0]]+['%.6f' % system_vector[1]]+['%.6f' % system_vector[2]]+['%.0f' % system_vector[3]]+['%.4f' % updatestuff.Predictedn]+['%.4f' % updatestuff.Predictede])
		datastring+=str(daughter_board)+cut_down
		print datastring
		log.write(datastring+"\r\n")
		ser_gr.write(reed_solomon.encode_string(callsign+datastring))         #all our telemetery over the radio link
		#log.write(reed_solomon.encode_string(callsign+datastring))
		#t=reed_solomon.encode_string(callsign+datastring)
		#print t
		#print reed_solomon.decode_string(t,[])
		if count==2:
			send_sms(datastring,mynumber)                          #every third time
			count=0
			os.system("sync")
		count+=1
		if calibrate==30:
			ser_daughter.write("K\r\n")                            #recalibrates the pressure sensor
			calibrate=0
		calibrate+=1
		if cut_down=='':
			if system_vector[3]/100>layercounter:                                 #100m altitude layers
				layercounter+=1                                               #we move up a layer
				up=Updatepredict(*system_vector)
				log.write(str(up)+"\r\n")
				if not are_we_inside([0],up[1],up[0],[0]):      #update and check against the polygon
					print "geofence cutdown"
					log.write("geofence cutdown\r\n")		
					cutdown()
					cut_down='CG'
			if system_vector[0]-startuptime>max_flight_time:
				print "time cutdown"
				log.write("time cutdown\r\n")
				cutdown()
				cut_down='CT'
			#if daughter_board[4]<battery_limit:
			#	print "voltage cutdown"
			#	log.write("voltage cutdown\r\n")		
			#	cutdown()
			#	cut_down='CB'
			if system_vector[3]-maxaltitude<-100:
				print "balloon popped"
				log.write("balloon popped\r\n")
				shutdown()
				cut_down='BP'
		if system_vector[3]>maxaltitude:
			maxaltitude=system_vector[3]
		if system_vector[3]>limit[0] and pump==FALSE:
			print 'turning on the pump (setting pressure target)'
			HV_enable(1)
			Set_pressure_target(default_target_pressure)
			log.write("HV1 on\r\n")
			pump=TRUE
			HV=1
		if system_vector[3]>limit[1] and HV==1:                          #set the right HV channel for the altitude                                
			HV_enable(2)
			log.write("HV2 on\r\n")
			HV=2
		if system_vector[3]>limit[2] and HV==2:
			HV_enable(3)
			log.write("HV3 on\r\n")	
			HV=3
		time.sleep(10)
		iterations+=1                                              #10 seconds sleep
 
finally:
	log.close()
#	ser_phone.write("AT+CFUN=0\r\n")      #phone off
	ser_phone.close()
	ser_gr.close()
	ser_daughter.close()
	print "bye"</code>