OPTION EXPLICIT
 OPTION DEFAULT NONE
 
 dim receivedData$ ' this is the string we received
 dim integer info(13) ' this is an array that will contain the 13 values we are looking for
   



sub getStuff receivedData$
 local integer tempData(32), n, datalength,checksum, check_high, check_low
 ' copy the string data into a numeric array
 for n = 1 to len(receivedData$)
   tempData(n) = asc(mid$(receivedData$,n,1))
 next n
 ' check to see if the starting values are "BM"
 if tempData(1) = asc("B") and tempData(2) = asc("M") then print "OK so far"
 ' the next two bytes tell us how long the data packet is. It should alwas be = 28 (2*13 + 2)
 dataLength = tempData(3)*256+tempData(4) ' tempData(3) should be 0 and tempData(4) = 28
 if dataLength = 28 then print "Still looks good"
 ' now we do a checksum by adding all the bytes and compare them with the checksum that was sent
 for n = 1 to 30
   checksum = checksum + tempData(n)
 next n
 check_low = checksum and 255
 check_high = (checksum /256) and 255
 if check_high = tempData(31) and if check_low = tempData(32) then print "check sum agrees!!!"
 ' if everything has gone well, it is safe to believe the data
 ' now we combine the high and low bytes for each of the 13 values
 for n = 1 to 13
   info(n) = tempData(n*2+3)*256+tempData(n*2+4)
 next n
 ' print the results
 for n = 1 to 13
   print info(n);",";
 next n
 print
end sub

OPTION EXPLICIT
OPTION DEFAULT NONE
DIM a$,b$
DIM as Integer c,d,e,f,g,h,i,j,k,l,m,n,o,p,particles_03um2,particles_05um2
DIM as Integer particles_10um2,particles_25um2,particles_50um2,particles_100um2
Open "COM1:9600" As #1

Do
a$ = INPUT$(1,#1)
b$ = b$ + a$
IF Len(b$) = 32 Then  ' valid data packets contain 32 characters
decode
b$ = ""
End IF
Loop

sub decode
IF left$(b$,2) = "BM" then ' Only proceed if probable Valid data is received
c = asc(mid$(b$,3)) 'Should be 0
d = asc(mid$(b$,4)) 'Should be 28
if c + d = 28 then ' data length is correct we probably have valid data
'do checksum here from asc(mid$(b$,31)) and asc(mid$(b$,32))  
'IF CHECKSUM = PREVIOUS CHECKSUM DISREGARD READING WE ONLY WANT DATA WITHOUT 2 CONSECUTIVE CHECKSUMS because unit sends data every second but only updates the readings every 2.3 seconds therefore we only want new data to display
'Only need values from Data7 high to Data12 low
e = asc(mid$(b$,17)) 'Data7 high
f = asc(mid$(b$,18)) 'Data 7 low
g = asc(mid$(b$,19)) 'Data 8 high
h = asc(mid$(b$,20)) 'Data 8 low
i = asc(mid$(b$,21)) 'Data 9 high
j = asc(mid$(b$,22)) 'Data 9 low
k = asc(mid$(b$,23)) 'Data 10 high
l = asc(mid$(b$,24)) 'Data 10 low
m = asc(mid$(b$,25)) 'Data 11 high
n = asc(mid$(b$,26)) 'Data 11 low
o = asc(mid$(b$,27)) 'Data 12 high
p = asc(mid$(b$,28)) 'Data 12 low
print e,f,g,h,i,j,k,l,m,n,o,p ' print all values to check
particles_03um2 = e + f  'value  I'm **ASSUMING** we add the values?
particles_05um2 = g + h  'value
particles_10um2 = i + j  'value
particles_25um2 = k + l  'value
particles_50um2 = m + n  'value
particles_100um2 = o + p 'value
print "Particles > 0.3um / 0.1L air: " STR$(particles_03um2)
print "Particles > 0.5um / 0.1L air: " STR$(particles_05um2)
print "Particles > 1.0um / 0.1L air: " STR$(particles_10um2)
print "Particles > 2.5um / 0.1L air: " STR$(particles_25um2)
print "Particles > 5.0um / 0.1L air: " STR$(particles_50um2)
print "Particles > 10.0 um / 0.1L air: " STR$(particles_100um2)
END IF
END IF
END SUB

 OPTION EXPLICIT
 OPTION DEFAULT NONE
 DIM a$,b$
 DIM as Integer c
 Open "COM1:9600" As #1
 
 Do
   a$ = INPUT$(1,#1)
   b$ = b$ + a$
   IF Len(b$) = 32 Then  ' valid data packets contain 32 characters
     decode
     b$ = ""
   End IF
 Loop
 
sub decode
 IF left$(b$,2) = "BM" then ' Only proceed if probable Valid data is received
   for c = 1 to 32
     print asc(mid$(b$,c))
   next c
 endif
end sub

 OPTION EXPLICIT
 OPTION DEFAULT NONE
 DIM a$,b$
 DIM as Integer c
 Open "COM1:9600" As #1
 
 Do
   a$ = INPUT$(1,#1)
   b$ = b$ + a$
   if len(b$) > 2 and left$(b$) <>"BM" then b$ = mid$(b$,2) ' synchronise the data stream
   IF Len(b$) = 32 Then  ' valid data packets contain 32 characters
     decode
     b$ = ""
   End IF
 Loop
 
sub decode
 IF left$(b$,2) = "BM" then ' Only proceed if probable Valid data is received
   for c = 1 to 32
     print asc(mid$(b$,c))
   next c
 endif
end sub

for n = 1 to 30
  checksum = checksum + asc(mid$(b$,n))
next n

checksum_sent = asc(mid$(b$,31))*256 + asc(mid$(b$,32))

if checksum = checksum_sent then print "Yippee!!!!"

 OPTION EXPLICIT
 OPTION DEFAULT NONE
 DIM a$,b$
 dim integer cs, css
 DIM as Integer c,d,e,f,g,h,i,j,k,l,m,n,o,p,particles_03um2,particles_05um2
 DIM as Integer particles_10um2,particles_25um2,particles_50um2,particles_100um2
 
 '  Open "COM1:9600" As #1
 
 '  Do
 '    a$ = INPUT$(1,#1)
 '    b$ = b$ + a$
 '        if len(b$) > 2 and left$(b$) <>"BM" then b$ = mid$(b$,2) ' synchronise the data stream
 '    IF Len(b$) = 32 Then  ' valid data packets contain 32 characters
 '      decode
 '      b$ = ""
 '    End IF
 '  Loop
 
 
 ' sample data taken from image ^@ = 0 and ^\ = 28
 for n = 1 to 32
   read p
   b$ = b$+chr$(p)
 next n
 
 decode
 print
 
 print "PM2.5 = ";asc(mid$(b$,7,1))*256+asc(mid$(b$,8,1))
 print "PM10  = ";asc(mid$(b$,9,1))*256+asc(mid$(b$,10,1))
end
 
sub decode
 IF left$(b$,2) = "BM" then ' Only proceed if probable Valid data is received
   c = asc(mid$(b$,3)) 'Should be 0
   d = asc(mid$(b$,4)) 'Should be 28
   if c*256 + d = 28 then ' data length is correct we probably have valid data
     css =asc(mid$(b$,31,1))*256+asc(mid$(b$,32,1))
     print "supplied check sum = ";css
     for n = 1 to 30
       cs = cs + asc(mid$(b$,n,1))
     next n
     print "calculated check sum = ";cs
     print "difference = ";cs-css
     'do checksum here from asc(mid$(b$,31)) and asc(mid$(b$,32))
     'IF CHECKSUM = PREVIOUS CHECKSUM DISREGARD READING WE ONLY WANT DATA WITHOUT 2 CONSECUTIVE CHECKSUMS because unit sends data every second but only updates the readings every 2.3 seconds therefore we only want new data to display
     'Only need values from Data7 high to Data12 low
     e = asc(mid$(b$,17)) 'Data7 high
     f = asc(mid$(b$,18)) 'Data 7 low
     g = asc(mid$(b$,19)) 'Data 8 high
     h = asc(mid$(b$,20)) 'Data 8 low
     i = asc(mid$(b$,21)) 'Data 9 high
     j = asc(mid$(b$,22)) 'Data 9 low
     k = asc(mid$(b$,23)) 'Data 10 high
     l = asc(mid$(b$,24)) 'Data 10 low
     m = asc(mid$(b$,25)) 'Data 11 high
     n = asc(mid$(b$,26)) 'Data 11 low
     o = asc(mid$(b$,27)) 'Data 12 high
     p = asc(mid$(b$,28)) 'Data 12 low
     print e,f,g,h,i,j,k,l,m,n,o,p ' print all values to check
     particles_03um2 = e*256 + f  'value  I'm **ASSUMING** we add the values?
     particles_05um2 = g*256 + h  'value
     particles_10um2 = i*256 + j  'value
     particles_25um2 = k*256 + l  'value
     particles_50um2 = m*256 + n  'value
     particles_100um2 = o*256 + p 'value
     print "Particles > 0.3um / 0.1L air: " STR$(particles_03um2)
     print "Particles > 0.5um / 0.1L air: " STR$(particles_05um2)
     print "Particles > 1.0um / 0.1L air: " STR$(particles_10um2)
     print "Particles > 2.5um / 0.1L air: " STR$(particles_25um2)
     print "Particles > 5.0um / 0.1L air: " STR$(particles_50um2)
     print "Particles > 10.0 um / 0.1L air: " STR$(particles_100um2)
   END IF
 END IF
END SUB
 
 
 data 66,77, 0,28,0,2,0,4,0,4,0,2,0,4,0,4
 data 2,97 ,0,24,0,28,0,2,0,0,0,0,23,0,2,111

for n = 1 to 32
  read p
  b$ = b$+chr$(p)
next n

for n = 1 to 32
   print asc(mid$(b$,n,1)); : print ",";
next n
print


decode

boolean readPMSdata(Stream *s) {
 if (! s->available()) {
   return false;
 }
 
 // Read a byte at a time until we get to the special '0x42' start-byte
 if (s->peek() != 0x42) {
   s->read();
   return false;
 }

 // Now read all 32 bytes
 if (s->available() < 32) {
   return false;
 }
   
 uint8_t buffer[32];    
 uint16_t sum = 0;
 s->readBytes(buffer, 32);

 // get checksum ready
 for (uint8_t i=0; i<30; i++) {
   sum += buffer[i];
 }

 /* debugging
 for (uint8_t i=2; i<32; i++) {
   Serial.print("0x"); Serial.print(buffer[i], HEX); Serial.print(", ");
 }
 Serial.println();
 */
 
 // The data comes in endian'd, this solves it so it works on all platforms
 uint16_t buffer_u16[15];
 for (uint8_t i=0; i<15; i++) {
   buffer_u16[i] = buffer[2 + i*2 + 1];
   buffer_u16[i] += (buffer[2 + i*2] << 8);
 }

 // put it into a nice struct :)
 memcpy((void *)&data, (void *)buffer_u16, 30);

 if (sum != data.checksum) {
   Serial.println("Checksum failure");
   return false;
 }
 // success!
 return true;
}