mirror of
https://github.com/RobTillaart/Arduino.git
synced 2024-10-03 18:09:02 -04:00
0.2.0 MHZCO2
This commit is contained in:
Rob Tillaart
parent
2d4dbde8f2
commit
06dede87d1
@ -6,13 +6,20 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
|
||||
and this project adheres to [Semantic Versioning](http://semver.org/).
|
||||
|
||||
|
||||
## [0.2.0] - 2023-12-29
|
||||
- Fix #9 bug in **setPPM()**
|
||||
- fix race condition in **receive()**
|
||||
- update readme.md
|
||||
- minor edits
|
||||
|
||||
----
|
||||
|
||||
## [0.1.4] - 2023-11-14
|
||||
- update readme.md
|
||||
- add plotter example (MEGA)
|
||||
- update keywords.
|
||||
- minor edits
|
||||
|
||||
|
||||
## [0.1.3] - 2023-07-27
|
||||
- remove MTP40F as it is not compatible
|
||||
- update examples.
|
||||
|
||||
@ -1,7 +1,7 @@
|
||||
//
|
||||
// FILE: MHZCO2.cpp
|
||||
// AUTHOR: Rob Tillaart
|
||||
// VERSION: 0.1.4
|
||||
// VERSION: 0.2.0
|
||||
// PURPOSE: Arduino Library for MHZ series CO2 sensors
|
||||
// DATE: 2020-05-05
|
||||
// URL: https://github.com/RobTillaart/MHZCO2
|
||||
@ -38,7 +38,10 @@ void MHZCO2::setPPM(uint16_t PPM)
|
||||
{
|
||||
_PPM = PPM;
|
||||
uint8_t data[9] = {0xFF, 0x01, 0x99, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
|
||||
data[8] = PPM >> 8;
|
||||
// as max value is lower than 65536 only two bytes need to be set.
|
||||
// data[4] = 0;
|
||||
// data[5[ = 0;
|
||||
data[6] = PPM >> 8;
|
||||
data[7] = PPM & 0xFF;
|
||||
data[8] = checksum(data);
|
||||
send(data, 9);
|
||||
@ -137,23 +140,32 @@ void MHZCO2::calibrateAuto(bool mode)
|
||||
void MHZCO2::send(uint8_t * data, uint8_t len)
|
||||
{
|
||||
_str->write(data, len);
|
||||
_str->flush();
|
||||
_str->flush(); // do not return until all data is sent.
|
||||
}
|
||||
|
||||
|
||||
int MHZCO2::receive(uint8_t * answer)
|
||||
{
|
||||
uint32_t start = millis();
|
||||
while (_str->available() == 0)
|
||||
|
||||
// need to read 9 bytes.
|
||||
uint8_t i = 0;
|
||||
while (i < 9)
|
||||
{
|
||||
if (millis() - start > 1000) return MHZCO2_TIMEOUT;
|
||||
}
|
||||
for (uint8_t i = 0; i < 9; i++)
|
||||
{
|
||||
answer[i] = _str->read();
|
||||
if (_str->available())
|
||||
{
|
||||
answer[i] = _str->read();
|
||||
i++;
|
||||
}
|
||||
else
|
||||
{
|
||||
// note: hardcoded timeout
|
||||
if (millis() - start > 1000) return MHZCO2_TIMEOUT;
|
||||
}
|
||||
}
|
||||
// verify checksum
|
||||
if (answer[8] != checksum(answer)) return MHZCO2_ERROR_CRC;
|
||||
|
||||
return MHZCO2_OK;
|
||||
}
|
||||
|
||||
@ -170,15 +182,6 @@ uint8_t MHZCO2::checksum(uint8_t *arr)
|
||||
}
|
||||
|
||||
|
||||
/* slightly faster
|
||||
uint8_t MHZCO2::checksum(uint8_t *arr)
|
||||
{
|
||||
uint8_t sum = 0xFF;
|
||||
for (uint8_t i = 1; i < 8; i++) sum -= arr[i];
|
||||
return sum + 1;
|
||||
}
|
||||
*/
|
||||
|
||||
|
||||
/////////////////////////////////////////////////////////
|
||||
//
|
||||
|
||||
@ -2,7 +2,7 @@
|
||||
//
|
||||
// FILE: MHZCO2.h
|
||||
// AUTHOR: Rob Tillaart
|
||||
// VERSION: 0.1.4
|
||||
// VERSION: 0.2.0
|
||||
// PURPOSE: Arduino Library for MHZ series CO2 sensors
|
||||
// DATE: 2020-05-05
|
||||
// URL: https://github.com/RobTillaart/MHZCO2
|
||||
@ -10,7 +10,7 @@
|
||||
|
||||
#include "Arduino.h"
|
||||
|
||||
#define MHZCO2_LIB_VERSION (F("0.1.4"))
|
||||
#define MHZCO2_LIB_VERSION (F("0.2.0"))
|
||||
|
||||
#define MHZCO2_OK 0
|
||||
#define MHZCO2_TIMEOUT -10
|
||||
@ -25,11 +25,13 @@ public:
|
||||
void begin(Stream * str);
|
||||
uint32_t uptime();
|
||||
|
||||
|
||||
// PPM = 2000, 5000, 10000 (other values unknown)
|
||||
// check datasheet
|
||||
void setPPM(uint16_t PPM);
|
||||
uint16_t getPPM();
|
||||
|
||||
|
||||
// MEASUREMENT
|
||||
int measure();
|
||||
uint32_t lastMeasurement();
|
||||
@ -38,12 +40,14 @@ public:
|
||||
int getAccuracy();
|
||||
int getMinCO2();
|
||||
|
||||
|
||||
// CALIBRATION
|
||||
// USE WITH CARE => READ DATASHEET!
|
||||
void calibrateZero();
|
||||
void calibrateSpan(uint16_t span);
|
||||
void calibrateAuto(bool mode = true);
|
||||
|
||||
|
||||
protected:
|
||||
Stream * _str;
|
||||
uint32_t _startTime;
|
||||
@ -61,6 +65,7 @@ protected:
|
||||
};
|
||||
|
||||
|
||||
|
||||
/////////////////////////////////////////////////////////
|
||||
//
|
||||
// DERIVED CLASSES
|
||||
|
||||
@ -25,19 +25,34 @@ This might change in the future as compatibles might differ on detail.
|
||||
|
||||
Reference: user manual MHZ129B 2019-04-25 version 1.4
|
||||
|
||||
#### Version 0.2.0
|
||||
|
||||
Version 0.2.0 fixes a bug in **setPPM()** which makes older versions obsolete.
|
||||
|
||||
|
||||
#### Compatibles
|
||||
|
||||
This list is not verified although these devices should be compatible based upon datasheet.
|
||||
|
||||
There exists different models of 400-2000 PPM and 400-5000 PPM and 400-10000 PPM.
|
||||
As far as known these have the same interface as there is very little information to be found.
|
||||
|
||||
|
||||
| type | precision | notes |
|
||||
|:-----------|:----------:|:--------|
|
||||
| MHZ1311A | 50ppm + 5% | energy saving version
|
||||
| MHZ19 | 50ppm + 5% |
|
||||
| MHZ19B | 50ppm + 3% | test device
|
||||
| MHZ19C | 50ppm + 5% |
|
||||
| MHZ19C | 50ppm + 5% | (1)
|
||||
| MHZ19D | 50ppm + 5% |
|
||||
| MHZ19E | 50ppm + 5% |
|
||||
|
||||
Note (1):
|
||||
There exists different models of the MHZ19C and probably others.
|
||||
The range can go from 400-2000 PPM, 400-5000 PPM and 400-10000 PPM.
|
||||
As far as known these have the same interface as there is very little
|
||||
information to be found. See #9.
|
||||
|
||||
Note: The calibration of the MHZ1311A is different than MHZ19x series
|
||||
|
||||
If there are compatible devices missing in this list, please let me know.
|
||||
@ -85,7 +100,8 @@ or a softwareSerial port.
|
||||
|
||||
#### Measure
|
||||
|
||||
- **int measure()** workhorse, send command to read the sensor.
|
||||
- **int measure()** workhorse, send command to read the sensor and
|
||||
waits until an answer is received. Return values see below.
|
||||
- **uint32_t lastMeasurement()** timestamp in milliseconds of last measurement.
|
||||
- **int getCO2()** returns CO2 PPM last measurement.
|
||||
- **int getTemperature()** returns temperature last measurement.
|
||||
@ -94,6 +110,16 @@ or a softwareSerial port.
|
||||
|
||||
The latter two might not be supported by all MH sensors.
|
||||
|
||||
|
||||
Return values of **measure()**
|
||||
|
||||
| value | Name | Description |
|
||||
|:-------:|:------------------:|:--------------|
|
||||
| 0 | MHZCO2_OK | measurement succeeded.
|
||||
| -10 | MHZCO2_TIMEOUT | to too long to receive an answer
|
||||
| -11 | MHZCO2_ERROR_CRC | Checksum error, handle answer with care.
|
||||
|
||||
|
||||
#### Calibration
|
||||
|
||||
**WARNING:** use with care, read the datasheet as these commands may disrupt your sensor.
|
||||
@ -118,7 +144,6 @@ See - https://keelingcurve.ucsd.edu/
|
||||
- improve documentation
|
||||
- buy hardware MHZ19B / MHZ19C
|
||||
- test with hardware
|
||||
- verify checksum
|
||||
- verify timeout
|
||||
|
||||
|
||||
@ -130,6 +155,8 @@ See - https://keelingcurve.ucsd.edu/
|
||||
|
||||
#### Could
|
||||
|
||||
- investigate configurable timeout. now hardcoded 1 second.
|
||||
- 2 bytes + 2 functions.
|
||||
- extend unit tests
|
||||
- add type info for derived classes?
|
||||
- A .. E ?
|
||||
|
||||
@ -15,7 +15,7 @@
|
||||
"type": "git",
|
||||
"url": "https://github.com/RobTillaart/MHZCO2.git"
|
||||
},
|
||||
"version": "0.1.4",
|
||||
"version": "0.2.0",
|
||||
"license": "MIT",
|
||||
"frameworks": "*",
|
||||
"platforms": "*",
|
||||
|
||||
@ -1,5 +1,5 @@
|
||||
name=MHZCO2
|
||||
version=0.1.4
|
||||
version=0.2.0
|
||||
author=Rob Tillaart <rob.tillaart@gmail.com>
|
||||
maintainer=Rob Tillaart <rob.tillaart@gmail.com>
|
||||
sentence=Arduino Library for MHZ series CO2 sensors.
|
||||
|
||||
Loading…
Reference in New Issue
Block a user