RF Communication using BS2sx
chazbrazil
Posts: 27
I'm currently working on a project that uses the BS2sx to take temperature readings with the Sensirion SHT1x module and relaying that information through RF modules to a home base. Ideally, the home base can support an "indefinate" amount of transmitters.
Code for the reciever, or base unit, is:
Note: Please forgive the disorganized manner.
Also, here is the code (much longer) for the transmitter. It's an adaptation of one of the modules posted on the parallax website:
·The data I'm recieving looks like this:
Where "A" is the name for the transmitter. Now values like "T789H472" make sense because it translates to "temperature: 78.9 and humidity: 47.2"... But the other data values like "T32378H65310" make no sense. Any clues?
Code for the reciever, or base unit, is:
' {$STAMP BS2sx}
' {$PBASIC 2.5}
x VAR Word
y VAR Word
tF VAR Word
tC VAR Word
rhTrue VAR Word
rhLin VAR Word
name VAR Byte
inbyte VAR Byte
SerBaud CON 240 + 16384 ' 9600 Baud, 'inverted'
SerPort CON 16
MyData VAR Byte
MyPin VAR IN4
LED CON 13
name = "A"
DO
GIVEUP:
DEBUG "Preparing... ", name, CR
PULSOUT 2, 3000
SEROUT 2, 17405, [noparse][[/noparse]name]
DEBUG "Request sent", CR
SERIN 0, 17405, 5000, GIVEUP1, [noparse][[/noparse]WAIT(name), x.HIGHBYTE, x.LOWBYTE, y.HIGHBYTE, y.LOWBYTE]
PAUSE 200
GOTO CONTINUE
GIVEUP1:
DEBUG "Gave up once... trying again.", CR
DEBUG "Preparing... ", name, CR
PULSOUT 2, 3000
SEROUT 2, 17405, [noparse][[/noparse]name]
DEBUG "Request sent", CR
SERIN 0, 17405, 5000, GIVEUP2, [noparse][[/noparse]WAIT(name), x.HIGHBYTE, x.LOWBYTE, y.HIGHBYTE, y.LOWBYTE]
PAUSE 200
CONTINUE:
tf = x
rhtrue = y
DEBUG name
SEROUT SerPort, SerBaud, [noparse][[/noparse]"T", DEC tf] ' Output as "0" or "1"
PAUSE 500
HIGH 13
SEROUT SerPort, SerBaud, [noparse][[/noparse]"H", DEC rhtrue] ' Output as "0" or "1"
PAUSE 500 ' Wait 1000 mSec
LOW 13
DEBUG CR
GIVEUP2:
PAUSE 10000
'name = name + 1
'IF name = 67 THEN
' name = 65
'ENDIF
LOOP
Note: Please forgive the disorganized manner.
Also, here is the code (much longer) for the transmitter. It's an adaptation of one of the modules posted on the parallax website:
' ==============================================================================
' {$PBASIC 2.5}
'
' File...... SHT11.BS2
' Purpose... Interface to Sensirion SHT11 temperature/humidity sensor
' E-mail.... [url=mailto:stamptech@parallax.com]stamptech@parallax.com[/url]
' Date...... 12/30/02
'
' {$STAMP BS2sx}
'
' ==============================================================================
' ------------------------------------------------------------------------------
' Program Description
' ------------------------------------------------------------------------------
'
' This program demonstrates the interface to the Sht1X and displays the raw data
' ------------------------------------------------------------------------------
' I/O Definitions
' ------------------------------------------------------------------------------
ShtData CON 3 ' bi-directional data
Clock CON 1
' ------------------------------------------------------------------------------
' Constants
' ------------------------------------------------------------------------------
ShtTemp CON %00011 ' read temperature
ShtHumi CON %00101 ' read humidity
ShtStatW CON %00110 ' status register write
ShtStatR CON %00111 ' status register read
ShtReset CON %11110 ' soft reset (wait 11 ms after)
Ack CON 0
NoAck CON 1
No CON 0
Yes CON 1
MoveTo CON 2 ' for DEBUG control
ClrRt CON 11 ' clear DEBUG line to right
DegSym CON 186 ' degrees symbol for DEBUG
' ------------------------------------------------------------------------------
' Variables
' ------------------------------------------------------------------------------
ioByte VAR Byte ' data from/to SHT1x
ackBit VAR Bit ' ack/nak from/to SHT1x
toDelay VAR Byte ' timeout delay timer
timeOut VAR Bit ' timeout status
soT VAR Word ' temp counts from SHT1x
soRH VAR Word ' humidity counts from SHT1x
rhLin VAR Word ' humidity; linearized
rhTrue VAR Word ' humidity; temp compensated
status VAR Byte ' SHT1x status byte
x VAR Word
y VAR Word
tF VAR Word
tC VAR Word
adjTemp VAR Byte
adjHumi VAR Byte
signTemp VAR Bit
signHumi VAR Bit
BtnWk VAR Byte
txpin CON 7
Baud9600 CON 110
HIGH txpin
PAUSE 100
SEROUT txpin, Baud9600, [noparse][[/noparse]17]
adjTemp = 0
adjHumi = 0
signTemp = 0
signHumi = 0
' ------------------------------------------------------------------------------
' EEPROM Data
' ------------------------------------------------------------------------------
' ------------------------------------------------------------------------------
' Initialization
' ------------------------------------------------------------------------------
Initialize:
GOSUB SHT_Connection_Reset ' reset device connection
PAUSE 250 ' let DEBUG window open
' ------------------------------------------------------------------------------
' Program Code
' ------------------------------------------------------------------------------
Sensor_Demo:
GOSUB SHT_Measure_Temp
Main:
DEBUG CLS
DEBUG "SHT1x Demo", CR
DEBUG "----------", CR
Main2:
GOSUB SHT_Measure_Temp
DEBUG MoveTo, 0, 3
DEBUG "Raw Data Temp: "
DEBUG DEC soT, ClrRt, CR
GOSUB SHT_Measure_Humidity
' DEBUG MoveTo, 0, 7
DEBUG "Raw Data Humidity: "
DEBUG DEC soRH, ClrRt, CR
x = soT
y = soRH
BUTTON 15, 0, 1,1, BtnWk, 0, NoPress1
IF signTemp = 0 THEN
adjTemp = adjTemp + 1
ELSE
IF adjTemp = 1 THEN
signTemp = 0
adjTemp = 0
ELSE
adjTemp = adjTemp - 1
ENDIF
ENDIF
GOTO MAIN2
NoPress1:
BUTTON 14, 0, 1,1, BtnWk, 0, NoPress2
IF signTemp = 0 THEN
IF adjTemp = 0 THEN
signTemp = 1
adjTemp = 1
ELSE
adjTemp = adjTemp - 1
ENDIF
ELSE
adjTemp = adjTemp + 1
ENDIF
GOTO MAIN2
NoPress2:
BUTTON 13, 0, 1,1, BtnWk, 0, NoPress3
IF signHumi = 0 THEN
adjHumi = adjHumi + 1
ELSE
IF adjHumi = 1 THEN
signHumi = 0
adjHumi = 0
ELSE
adjHumi = adjHumi - 1
ENDIF
ENDIF
GOTO MAIN2
NoPress3:
BUTTON 12, 0, 1,1, BtnWk, 0, NoPress4
IF signHumi = 0 THEN
IF adjHumi = 0 THEN
signHumi = 1
adjHumi = 1
ELSE
adjHumi = adjHumi - 1
ENDIF
ELSE
adjHumi = adjHumi + 1
ENDIF
GOTO MAIN2
NoPress4:
tF = x ** 11796 - 400
tC = x / 10 - 400
'DEBUG CLS, DEC (tF / 10), ".", DEC1 tF, CR
rhLin = (y ** 26542)
rhLin = rhLin - ((y ** 3468) * (y ** 3468) + 50 / 100)
rhLin = rhLin - 40
rhTrue = ((tC / 10 - 25) * (y ** 524 + 1) + (rhLin * 10)) + 5 / 10
'DEBUG DEC (rhTrue / 10), ".", DEC1 rhTrue, CR
IF signTemp = 0 THEN
tF = tF + adjTemp
ELSE
tF = tF - adjTemp
ENDIF
IF signHumi = 0 THEN
rhTrue = rhTrue + adjHumi
ELSE
rhTrue = rhTrue - adjHumi
ENDIF
DEBUG "Begin waiting...", CR
SERIN 9, 17405, [noparse][[/noparse]WAIT("A")]
DEBUG "End waiting...", CR
PAUSE 300
PULSOUT 5, 3000
SEROUT 5, 17405, [noparse][[/noparse]"A", tF.HIGHBYTE, tF.LOWBYTE, rhTrue.HIGHBYTE, rhTrue.LOWBYTE]
HIGH txpin
PAUSE 100
SEROUT txpin, Baud9600, [noparse][[/noparse]22]
SEROUT txpin, Baud9600, [noparse][[/noparse]17]
'PAUSE 100
'SEROUT txpin, Baud9600, [noparse][[/noparse]"SHOVE IT!"]
'PAUSE 10
SEROUT txpin, Baud9600, [noparse][[/noparse]13]
'PAUSE 10
SEROUT txpin, Baud9600, [noparse][[/noparse]" Temp: ", SDEC (tF / 10), ".", SDEC1 tF, " F"]
'PAUSE 10
SEROUT txpin, Baud9600, [noparse][[/noparse]13]
'PAUSE 10
SEROUT txpin, Baud9600, [noparse][[/noparse]" Humi: ", SDEC (rhTrue / 10), ".", SDEC1 rhTrue, " %"]
'PAUSE 10
SEROUT txpin, Baud9600, [noparse][[/noparse]128]
'PAUSE 100
PAUSE 1000 ' minimum delay between readings
GOTO Main2
' ------------------------------------------------------------------------------
' Subroutines
' ------------------------------------------------------------------------------
' connection reset: 9 clock cyles with ShtData high, then start sequence
'
SHT_Connection_Reset:
SHIFTOUT ShtData, Clock, LSBFIRST, [noparse][[/noparse]$FFF\9]
'
SHT_Start:
INPUT ShtData ' let pull-up take line high
LOW Clock
HIGH Clock
LOW ShtData
LOW Clock
HIGH Clock
INPUT ShtData
LOW Clock
RETURN
SHT_Measure_Temp:
GOSUB SHT_Start ' alert device
ioByte = ShtTemp ' temperature command
GOSUB SHT_Write_Byte ' send command
GOSUB SHT_Wait ' wait until measurement done
ackBit = Ack ' another read follows
GOSUB SHT_Read_Byte ' get MSB
soT.HIGHBYTE = ioByte
ackBit = NoAck ' last read
GOSUB SHT_Read_Byte ' get LSB
soT.LOWBYTE = ioByte
' Note: Conversion factors are multiplied by 10 to return the
' temperature values in tenths of degrees
RETURN
' measure humidity
'
SHT_Measure_Humidity:
GOSUB SHT_Start ' alert device
ioByte = ShtHumi ' humidity command
GOSUB SHT_Write_Byte ' send command
GOSUB SHT_Wait ' wait until measurement done
ackBit = Ack ' another read follows
GOSUB SHT_Read_Byte ' get MSB
soRH.HIGHBYTE = ioByte
ackBit = NoAck ' last read
GOSUB SHT_Read_Byte ' get LSB
soRH.LOWBYTE = ioByte
RETURN
SHT_Write_Status:
GOSUB SHT_Start ' alert device
ioByte = ShtStatW ' write to status reg command
GOSUB SHT_Write_Byte ' send command
ioByte = status
GOSUB SHT_Write_Byte
RETURN
SHT_Read_Status:
GOSUB SHT_Start ' alert device
ioByte = ShtStatW ' write to status reg command
GOSUB SHT_Read_Byte ' send command
ackBit = NoAck ' only one byte to read
GOSUB SHT_Read_Byte
RETURN
SHT_Write_Byte:
SHIFTOUT ShtData, Clock, MSBFIRST, [noparse][[/noparse]ioByte] ' send byte
SHIFTIN ShtData, Clock, LSBPRE, [noparse][[/noparse]ackBit\1] ' get ack bit
RETURN
SHT_Read_Byte:
SHIFTIN ShtData, Clock, MSBPRE, [noparse][[/noparse]ioByte] ' get byte
SHIFTOUT ShtData, Clock, LSBFIRST, [noparse][[/noparse]ackBit\1] ' send ack bit
INPUT ShtData ' release data line
RETURN
SHT_Wait:
INPUT ShtData ' data line is input
FOR toDelay = 1 TO 250 ' give ~1/4 second to finish
timeOut = INS.LOWBIT(ShtData) ' scan data line
IF (timeOut = No) THEN SHT_Wait_Done ' if low, we're done
PAUSE 1
NEXT
SHT_Wait_Done:
RETURN
SHT_Soft_Reset:
GOSUB SHT_Connection_Reset ' reset the connection
ioByte = ShtReset ' reset command
ackBit = NoAck ' only one byte to send
GOSUB SHT_Write_Byte ' send it
PAUSE 11 ' wait at least 11 ms
RETURN
·The data I'm recieving looks like this:
Where "A" is the name for the transmitter. Now values like "T789H472" make sense because it translates to "temperature: 78.9 and humidity: 47.2"... But the other data values like "T32378H65310" make no sense. Any clues?
Comments
·· What transmitters and receivers are you using?· It sounds like what is happening is that multiple transmitters are sending data at the same time and the receiver is getting the extra data mixed in sometimes.· Ideally to have multiple transmitters you would need to set up a polled-system where each unit actually has a transmitter and receiver.· Thebase would send out the address of the first station and only that station would reply.· Then it would poll/query the second station and so on.· In this manner only one system is transmitting at any given time.
Your other option is to use something like the EB500 which is addressable.· That way you could specify the connections by MAC Address.· I hope this helps.· Take care.
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Chris Savage
Parallax Tech Support
csavage@parallax.com