I am not sure if this is the place to turn to because this is more of a sensor issue than a boron issue. I have scoured the web for information and can’t find anything that actually works.
I am trying to use a Senseaire S8 CO2 sensor. There is a decent amount of code for this sensor in the Arduino world, which is great. I thought I could port this code over to the Boron LTE and get it to work. I got it to work with a caveat. The boron transmits the data exactly how I expect it to, verified using a logic analyzer. However, the S8 sensor refuses to transmit any data back.
I am lost at this point. I have poured over the sensors datasheet, quadruple checked my connections, tried a second S8 sensor, and so on. I just not seem to want to work for me.
Any help or guidance would be greatly appreciated.
//Read Sequence from Modbus data sheet (pg.13)
byte CO2_read[8] = {0xFE, 0X04, 0X00, 0X00, 0X00, 0X01, 0X25, 0XC5};
byte response[] = {0, 0, 0, 0, 0, 0, 0};
void setup() {
Serial.begin(9600);
Serial1.begin(9600);
}
void loop() {
getCO2();
unsigned long CO2 = CO2count();
//delay(2000);
}
void getCO2(){
while(!Serial1.available())
{
Serial1.write(CO2_read,8);
delay(50);
}
int timeout = 0;
while(Serial1.available() < 6 ){
timeout++;
if (timeout > 10){
while(Serial1.available())
Serial1.read();
break;
}
delay(50);
}
for (int i = 0; i < 6; i++){
response[i] = Serial1.read();
}
}
unsigned long CO2count()
{
int high = response[3];
int low = response[4];
unsigned long val = high * 256 + low;
return val * 1; // S8 = 1. K-30 3% = 3, K-33 ICB = 10
}
Can you double check what power the sensor accepts? It looks like the sensor is using a 5V logic levels, and the Boron use a 3V3 logic levels. I think that the main problem could be a hardware issue related to the logical level of communication in the UART port.
I have already looked at that. The sensor data sheet says it is powered via 5 V, but uses 3.3 V logic logic levels with the UART communication. I have my setup configured as such.
Hi, sorry for a late response, finally I got some free time
You could try this: Particle Web IDE
and let’s see if will read correctly according to Senseair Modbus should read status and CO2 at once
I apologize for not responding yesterday, but I finally figured out the issue I was having yesterday evening.
It turns out that the CO2 sensor uses half-duplex in the UART transmission. So, the sensor can read or write data but not simultaneously. I was trying to write to the sensor too quickly and did not give the sensor enough time to respond.
I added a longer delay, and the sensor started responding with data.
I appreciate your help and will refer to your code to see what you did as well.
I am trying a similar setup as yours, only using a photon in stead of a Boron. Which delay did you increase?
I have tried your code but I cannot seem to get a value from the S8 sensor.
I’m had a problem getting the serial to display anything, so I tried the Particle.variable instead.
This just returns “0”
//Read Sequence from Modbus data sheet (pg.13)
byte CO2_read[8] = {0xFE, 0X04, 0X00, 0X00, 0X00, 0X01, 0X25, 0XC5};
byte response[] = {0, 0, 0, 0, 0, 0, 0};
unsigned long CO2;
void setup() {
Serial.begin(9600);
Serial1.begin(9600);
Particle.variable("CO2", CO2);
}
void loop() {
getCO2();
CO2 = CO2count();
delay(5000);
}
void getCO2(){
while(!Serial1.available())
{
Serial1.write(CO2_read,8);
delay(50);
}
int timeout = 0;
while(Serial1.available() < 6 ){
timeout++;
if (timeout > 10){
while(Serial1.available())
Serial1.read();
break;
}
delay(5000);
}
for (int i = 0; i < 6; i++){
response[i] = Serial1.read();
}
}
unsigned long CO2count()
{
int high = response[3];
int low = response[4];
unsigned long val = high * 256 + low;
return val * 1; // S8 = 1. K-30 3% = 3, K-33 ICB = 10
}
