Jonas Skalman
Reading SenseAir LP8 CO2 sensor over bluetooth low energy
Dependencies: BLE_API mbed nRF51822
Diff: LP8.h
- Revision:
- 2:d02255d8c36f
- Parent:
- 1:b512a405b584
- Child:
- 3:933dd59ad44d
diff -r b512a405b584 -r d02255d8c36f LP8.h
--- a/LP8.h Mon Jun 05 11:10:28 2017 +0000
+++ b/LP8.h Mon Aug 14 20:52:48 2017 +0000
@@ -1,17 +1,18 @@
#ifndef LP8_H
#define LP8_H
-/* To initialize the lp8 object, you need to pass a serial (tx, rx), an DigitalOut signal for the en_vbb,
-an DigitalIn for the ready signal and a timer object. */
+/* To initialize the lp8 object, you need to pass a serial (tx, rx), a DigitalOut signal for the en_vbb,
+an DigitalIn for the ready signal, DigitalOut for Reset and a timer object. */
class LP8
{
public:
//constructor
- LP8(Serial &device, DigitalOut &vbb_en, DigitalIn &rdy, Timer &_timer):
+ LP8(Serial &device, DigitalOut &vbb_en, DigitalIn &rdy, DigitalOut &res ,Timer &_timer):
Device(device),
VBB_EN(vbb_en),
RDY(rdy),
+ RES(res),
lp8Wait(_timer)
{
Device.baud(9600); //set baud rate to 9600
@@ -52,15 +53,22 @@
co2 = 400; //co2 value
counter = 0; //
CRC = 0x0000; //crc value
- _timeMe = 0.350; //wait timer(ms)
+
};
-//LP8 Initialization .
+//LP8 Initialization and first message
bool lp8Init(){
+
+// //Reset LP8
+// RES.write( 0 ); //reset
+// timeIt( 1.2 );
+// RES.write( 1 ); //enable
+
+ //Enable Sensor
VBB_EN.write( 1 ); //power on
//wait for rdy signal
- timeIt( _timeMe ); //wait for lp8 rdy signal
+ timeIt( 0.35 ); //wait for lp8 rdy signal
transmitPacket(firstWrite, 8); //Send out msg (and nr of bytes) over serial line
Response( 4 ); //read 4 bytes response
//compute crc
@@ -69,10 +77,11 @@
stateRead[5] = (uint8_t)CRC; //crc_l
stateRead[6] = (uint8_t)(CRC >> 8); //crc_h
//wait for rdy
- timeIt( _timeMe ); //
+ timeIt( 0.35 ); //
transmitPacket(stateRead, 7); //transmit packet
Response( 49 ); //read sensor state and co2 value(s)
VBB_EN.write( 0 ); //power off lp8
+
//was the talk a success? (simple check...)
if ( getValue() < 1 ) {
return 1; }
@@ -82,6 +91,7 @@
//send subsequent messages to the lp8
void lp8Talk(uint8_t ccByte){
+
//transfer previous sensor state to the new msg out
for (int u = 4; u < 23+4; u++) {
stateWrite[u+2] = response[u];
@@ -93,9 +103,10 @@
//add new crc value to send list
stateWrite[29] = (uint8_t)CRC;
stateWrite[30] = (uint8_t)(CRC >> 8);
+
//initialize new transfer sequence
VBB_EN.write( 1 ); //power on sensor
- timeIt( _timeMe );
+ timeIt( 0.35 );
transmitPacket(stateWrite, 31); //Send out msg with previous state (and nr of elements) over serial line
Response( 4 ); //read 4 bytes response
//compute crc
@@ -103,7 +114,7 @@
//add crc value to the read request transmit package
stateRead[5] = (uint8_t)CRC; //crc_l
stateRead[6] = (uint8_t)(CRC >> 8); //crc_h
- timeIt( _timeMe );
+ timeIt( 0.35 );
//send read request
transmitPacket(stateRead, 7); //transmit packet
//read sensor response
@@ -111,8 +122,8 @@
VBB_EN.write( 0 ); //power off
};
-//get co2 value from lp8 response
- unsigned long getValue()
+//get value from lp8 response
+ unsigned long getValue() /* CO2 Value */
{
int high = response[29];
int low = response[30];
@@ -120,10 +131,47 @@
return val;
}
-
+
+ double getTempValue()
+ {
+ int h = response[33];
+ int l = response[34];
+ unsigned long _temp = h * 256 + l;
+
+ double _tempVal = 0.01 * _temp;
+
+ return _tempVal;
+ }
+
+ int getVcapValue(){
+
+ int hB = response[35];
+ int lB = response[36];
+ unsigned long temp = hB * 256 + lB;
+
+ return temp;
+ }
+
+ uint32_t getErrorStatus(){
+
+ uint32_t tmp = 0;
+ tmp += response[39] << (32-8);
+ tmp += response[40] << (32-16);
+ tmp += response[41] << (32-24);
+ tmp += response[42];
+
+ return tmp;
+ }
+
+ //get calculation Control byte from lp8 response
+ uint8_t getCCbyte(){
+ uint8_t responseCCbyte = response[0];
+ return responseCCbyte;
+ }
+
/************************************************* Helper Functions ********************************************/
-/************************************************* ********************************************/
+
//purge response buffer
void responsePurge(int bytesToPurge){
for (int j = 0; j < bytesToPurge; j++) {
@@ -131,7 +179,7 @@
}
};
-//read from the lp8
+//read response from lp8 (not energy efficient...)
void Response(int bytesToRead ){
lp8Wait.start(); //poll rx line for 0.5 seconds
do {
@@ -140,7 +188,7 @@
counter++;
}
}
- while( lp8Wait.read() < 0.5 );
+ while( lp8Wait.read() < 0.2 );
counter = 0;
lp8Wait.stop();
lp8Wait.reset();
@@ -157,7 +205,7 @@
};
//timer
- void timeIt(float &timeMe){
+ void timeIt(float timeMe){
//start amd stop timer...
lp8Wait.start();
while (lp8Wait.read() < timeMe ) { /* W A I T I N G */ }
@@ -187,10 +235,12 @@
//variables and buffers
private:
-
+ //pins
Serial &Device;
DigitalOut &VBB_EN;
DigitalIn &RDY;
+ DigitalOut &RES;
+
Timer &lp8Wait;
//msg containers
@@ -198,11 +248,12 @@
uint8_t stateWrite[31];
uint8_t stateRead[7];
uint8_t response[60];
-
- int co2; //CO2 initial value
+
+ //
+ int co2; //CO2 initial value
+ int tempValue;
int counter; //simple counter
uint16_t CRC; //modbus crc value
- float _timeMe; //timer value
};