finalizations and debugging

LICENSE.txt

@@ -0,0 +1,18 @@
+Out of abundance of caution, all code in this project should be considered available for private educational use only,
+with no redistribution permitted in any form. Some files are available as MIT.
+
+Ask for clarification if needed: ondra@ondrovo.com
+
+
+~~ Licensing for individual components ~~
+
+Console
+
+proprietary (c) VZLU 2021, developed for VZLUSAT2 with CSP parts removed in this version.
+Inspired by the esp32 console, including a modified 3rd party Linenoise library, and argtable3.
+
+BSEC
+by Bosch, see the bme680 lib for details
+
+Web templating, telnet protocol, tcp socket server and the actual metering app
+(c) Ondřej Hruška 2018-2022, these components are MIT.

README.md

@@ -0,0 +1,55 @@
+# ESP air quality sensor
+
+## Function
+
+- CO2 ppm
+- air temperature
+- relative humidity
+- gas sensor VOC equivalent PPM
+- gas sensor CO2 equivalent PPM
+
+### Data reading
+
+The module prints actual readings to the debug console.
+
+Data is accessible as JSON on a REST endpoint /sample, port 80
+
+Example:
+
+```
+{"temp":22.80,"temp_r":22.86,"hum":45.33,"hum_r":45.15,"pres":98203.7,"gas_r":583406.1,"co2":620.00}
+```
+
+More data is included once BSEC2 (Bosch proprietary BME680 client / fusion library) finishes its calibration. See the `websrv.c` file for details.
+
+### Workarounds & reliability features
+
+The used CO2 sensor has buggy ABC algorithm that sometimes underflows. Further, I2C is very much broken on the sample used, so I use the Modbus interface instead.
+Automatic restart and calibration restore is implemented for it.
+
+BSEC2 state persistence is implemented, but dubious if functional due to the millisecond timestamp logic. Air quality reports usually start coming after a couple hours of run time with varying ambient gas concentration.
+
+### Configuration
+
+Config via console on the serial port (115200-8-N-1), or telnet (port 22).
+
+WiFi can be configured and persisted, including static IP. WiFi scan is not implemented.
+
+## Hardware
+
+- BME680 in I2C mode
+- SenseAir Sunrise (buggy early revision, will need updating for newer sensors)
+
+## Pinout
+
+- I2C_SDA0 16 - i2c for BME680
+- I2C_SCL0 17
+- I2C_SDA1 5 (senseair sunrise uart TX)
+- I2C_SCL1 18 (senseair sunrise uart RX)
+- CO2_NRDY 23
+- CO2_COMSEL 13 (high=uart)
+- CO2_EN 15 sunrise restart pin, works like nReset
+
+## Licensing
+
+See the LICENSE file.

main/co2_sensor.c

@@ -28,14 +28,25 @@ static int mb_write_and_read(uint8_t *buffer, int num, size_t resplen) {
         return 0;
     }
 
+    // sometimes there's trash in the buffer, get rid of it
+    int discarded = 0;
+    uint8_t junk;
+    do {
+        discarded = uart_read_bytes(CO2_UART_NUM, &junk, 1, pdMS_TO_TICKS(2));
+    } while(discarded);
+
     ESP_LOGD(TAG, "Sending");
     ESP_LOG_BUFFER_HEXDUMP(TAG, buffer, num, ESP_LOG_DEBUG);
     uart_write_bytes(CO2_UART_NUM, buffer, num);
 
     ESP_LOGD(TAG, "Expect resp of %d bytes", resplen);
-    num = uart_read_bytes(CO2_UART_NUM, buffer, resplen, pdMS_TO_TICKS(500));
+    num = uart_read_bytes(CO2_UART_NUM, buffer, resplen, pdMS_TO_TICKS(TIMEOUT_MS));
     ESP_LOGD(TAG, "Received %d bytes", num);
     ESP_LOG_BUFFER_HEXDUMP(TAG, buffer, num, ESP_LOG_DEBUG);
+
+    if (num == 0) {
+        ESP_LOGE(TAG, "No modbus response!");
+    }
     return num;
 }
 
@@ -50,7 +61,7 @@ static void write_saved_calib_to_sensor() {
 
         /* Write calib */
         resplen = 0;
-        num = mb_build_fc16(buffer, 128, &resplen, 104, 4, g_Settings.co2_calib, 5);
+        num = mb_build_fc16(buffer, 128, &resplen, CO2_ADDR, 4, g_Settings.co2_calib, 5);
         num = mb_write_and_read(buffer, num, resplen);
         resp = mb_parse_fc16(buffer, num);
         if (resp < 0) {
@@ -65,7 +76,7 @@ void co2_restart(bool restore_calib) {
     ESP_LOGI(TAG, "Restarting CO2 sensor");
 
     gpio_set_level(CONFIG_PIN_CO2_EN, 0);
-    vTaskDelay(pdMS_TO_TICKS(100));
+    vTaskDelay(pdMS_TO_TICKS(250));
     gpio_set_level(CONFIG_PIN_CO2_EN, 1);
     vTaskDelay(pdMS_TO_TICKS(50));
 
@@ -81,6 +92,8 @@ static bool ppm_looks_valid(uint16_t ppm) {
 void co2_read_task(void *param) {
     (void) param;
 
+    // 68 04 0a 00 00 00 00 00 00 03 b5 03 f2 dd c3
+
     vTaskDelay(pdMS_TO_TICKS(500));
 
     // TODO
@@ -107,14 +120,14 @@ void co2_read_task(void *param) {
         ppm = 0;
         vTaskDelay(read_cycle_time_ticks);
 
-        if (num_fails > 10) {
+        if (num_fails > 5) {
             ESP_LOGW(TAG, "Too many CO2 fails, restarting sensor");
             co2_restart(true);
             num_fails = 0;
         }
 
         resplen = 0;
-        num = mb_build_fc4(buffer, 128, &resplen, 104, 0, 5);
+        num = mb_build_fc4(buffer, 128, &resplen, CO2_ADDR, 0, 5);
         num = mb_write_and_read(buffer, num, resplen);
         qty = mb_parse_fc4(buffer, num, values, 32);
         if (qty < 0) {
@@ -175,7 +188,10 @@ void co2_read_task(void *param) {
 
         if (!ppm_looks_valid(ppm)) {
             ESP_LOGW(TAG, "CO2 measures nonsense!");
-            co2_restart(true);
+            if (ppm != 0) {
+                // ppm=0 is OK, it means the ppm wasn't measured yet. just ignore it.
+                co2_restart(true);
+            }
         } else {
             // CO2 measurement looks OK
 
@@ -187,7 +203,7 @@ void co2_read_task(void *param) {
                 last_calib_persist = tickNow;
 
                 resplen = 0;
-                num = mb_build_fc3(buffer, 128, &resplen, 104, 4, 5);
+                num = mb_build_fc3(buffer, 128, &resplen, CO2_ADDR, 4, 5);
                 num = mb_write_and_read(buffer, num, resplen);
                 qty = mb_parse_fc3(buffer, num, values, 32);
                 if (qty < 0) {

main/modbus_fn.c

@@ -1,3 +1,6 @@
+
+//#define LOG_LOCAL_LEVEL ESP_LOG_DEBUG
+
 #include <assert.h>
 #include "modbus_fn.h"
 #include "modbus_crc.h"
@@ -9,6 +12,9 @@ static bool crc_matches(const uint8_t *buf, size_t len) {
     assert(buf);
     uint16_t real = modbus_crc(buf, len - 2);
     uint16_t given = ((uint16_t) buf[len - 2] << 8) | (uint16_t) buf[len - 1];
+    if (real != given) {
+        ESP_LOGE(TAG, "CRC computed of %d bytes: %04x, given %04x", len-2, real, given);
+    }
     return real == given;
 }
 

main/periph_init.c

@@ -103,7 +103,10 @@ esp_err_t periph_init() {
         }
 
         gpio_set_level(CONFIG_PIN_CO2_COMSEL, 1); // low=I2C
-        gpio_set_level(CONFIG_PIN_CO2_EN, 1); // active high
+
+        gpio_set_level(CONFIG_PIN_CO2_EN, 0);
+        vTaskDelay(pdMS_TO_TICKS(250));
+        gpio_set_level(CONFIG_PIN_CO2_EN, 1);
     }
 
     // input