{"id":1238,"date":"2024-06-02T13:10:39","date_gmt":"2024-06-02T12:10:39","guid":{"rendered":"https:\/\/www.vatland.no\/?p=1238"},"modified":"2024-06-02T13:10:44","modified_gmt":"2024-06-02T12:10:44","slug":"my-simple-keg-scale","status":"publish","type":"post","link":"https:\/\/www.vatland.no\/index.php\/my-simple-keg-scale\/","title":{"rendered":"My ‘simple’ keg scale"},"content":{"rendered":"\n
\"\"<\/a><\/figure>\n\n\n\n

Since Plaato is retiring their Keg scale in 2024\/25 I had to find a new solution. Searching the web lead me to GitHub – Callwater\/Beerkeg-load-cell<\/a>. Since I had some ESP and loadcells at my hands it was very quick to setup. Had some wood and a router in my ‘workshop’ so made the base in a short time. Soldering all parts together and gluing them to the base. <\/p>\n\n\n\n

\"\"<\/a><\/figure>\n\n\n\n

The basic hardware and software was quickly up and running. <\/p>\n\n\n\n

Added a MQTT server to my HomeAssistant instance to prepare for some data presentation. Since there already was a mqtt client library ready for node-mcu – esp8266 it was nearly a walk in the park.<\/p>\n\n\n\n

\"\"<\/a><\/figure>\n\n\n\n

Code was added using Visual Studio Code.<\/p>\n\n\n\n

File : main.cpp<\/p>\n\n\n

\n#include <Arduino.h>\n#include <DHT.h>\n#include <DHT_U.h>\n#include <HX711.h>\n#include <ESP8266WiFi.h>\n#include <PubSubClient.h>\n#include <SPI.h>\n#include <Wire.h>\n#include <Adafruit_GFX.h>\n#include <Adafruit_SSD1306.h>\n\n#define SCREEN_WIDTH 128 \/\/ OLED display width, in pixels\n#define SCREEN_HEIGHT 64 \/\/ OLED display height, in pixels\n\n#include "config.h"\n#define OLED_RESET -1       \/\/ Reset pin # (or -1 if sharing Arduino reset pin)\n#define SCREEN_ADDRESS 0x3c \/\/\/< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32\nAdafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);\n\nDHT dht{DHT_PIN, DHT_TYPE};      \/\/ Initiate DHT library\nHX711 scale;                     \/\/ Initiate HX711 library\nWiFiClient wifiClient;           \/\/ Initiate WiFi library\nPubSubClient client(wifiClient); \/\/ Initiate PubSubClient library\nint publishcount = 10;           \/\/ Do 10 mqtt publishes - then force reconnect\nbool displayconnected = true;\nfloat prevmeter = 1000.0;\nint screentimeout = 10;\nvoid reconnect();\nvoid callback(char *topic, byte *payload, unsigned int length);\nvoid drawText(float temperature, float volume, float humidity, String Message);\nvoid drawMessage(String message);\nvoid screenoff();\nvoid setup()\n{\n  Serial.begin(74880);\n  Serial.println();\n  WiFi.mode(WIFI_STA);\n  WiFi.begin(SSID, PASSWORD);\n  Serial.print("Connecting...");\n  while (WiFi.status() != WL_CONNECTED)\n  { \/\/ Wait till Wifi connected\n    delay(500);\n    Serial.print(".");\n  }\n  Serial.println();\n\n  Serial.print("Connected.IP address:");\n  Serial.println(WiFi.localIP()); \/\/ Print IP address\n  delay(2000);\n  \/\/ SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally\n  if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS))\n  {\n    Serial.println(F("SSD1306 allocation failed"));\n    \/\/ for(;;); \/\/ Don't proceed, loop forever\n    displayconnected = false;\n  }\n  else\n  {\n    Serial.println(F("SSD1306 allocation success"));\n    displayconnected = true;\n    display.clearDisplay();\n    display.display();\n  };\n\n  if (displayconnected)\n  {\n    drawMessage("Connected IP address:");\n    delay(2000);\n    drawMessage(WiFi.localIP().toString());\n    delay(2000);\n  }\n  client.setServer(MQTT_SERVER, 1883);              \/\/ Set MQTT server and port number\n  client.setCallback(callback);                     \/\/ Set callback address, this is used for remote tare\n  scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN); \/\/ Start scale on specified pins\n  scale.wait_ready();                               \/\/ Ensure scale is ready, this is a blocking function\n  scale.set_scale();\n  Serial.println("Scale Set");\n  scale.wait_ready();\n  scale.tare(); \/\/ Tare scale on startup\n  scale.wait_ready();\n  Serial.println("Scale Zeroed");\n\n  Serial.println("Start DHT library");\n  dht.begin();\n}\n\nvoid loop()\n{\n  float reading;                       \/\/ Float for reading\n  float raw;                           \/\/ Float for raw value which can be useful\n  scale.wait_ready();                  \/\/ Wait till scale is ready, this is blocking if your hardware is not connected properly.\n  scale.set_scale(calibration_factor); \/\/ Sets the calibration factor.\n  scale.set_offset(offset_factor);     \/\/ Sets offset for empty keg\n  if (publishcount < 1)\n  {\n    \/\/ reconnect();\n    client.disconnect();\n    publishcount = 10;\n    \/\/ Serial.println("Scheduled reconnect.");\n  }\n  publishcount--;\n\n  \/\/ Ensure we are still connected to MQTT Topics\n  if (!client.connected())\n  {\n    reconnect();\n  }\n\n  Serial.print("Reading: "); \/\/ Prints weight readings in .2 decimal kg units.\n  scale.wait_ready();\n  reading = scale.get_units(10); \/\/ Read scale in g\/Kg\n  raw = scale.read_average(5);   \/\/ Read raw value from scale too\n  Serial.print(reading, 1);\n  Serial.println(" L");\n  Serial.print("Raw: ");\n  Serial.println(raw);\n  Serial.print("Calibration factor: "); \/\/ Prints calibration factor.\n  Serial.println(calibration_factor);\n\n  if (reading < 0)\n  {\n    reading = 0.00; \/\/ Sets reading to 0 if it is a negative value, sometimes loadcells will drift into slightly negative values\n  }\n\n  String value_str = String(reading);\n  String value_raw_str = String(raw);\n  client.publish(STATE_TOPIC, value_str.c_str());         \/\/ Publish weight to the STATE topic\n  client.publish(STATE_RAW_TOPIC, value_raw_str.c_str()); \/\/ Publish raw value to the RAW topic\n\n  client.loop();      \/\/ MQTT task loop\n  scale.power_down(); \/\/ Puts the scale to sleep mode for 3 seconds. I had issues getting readings if I did not do this\n  delay(3000);\n  scale.power_up();\n\n  \/\/ Reading values from the DHT sensor\n  float humidity = dht.readHumidity();       \/\/ Read humidity\n  float temperature = dht.readTemperature(); \/\/ Read temperature\n\n  \/\/ Check if we recieved a number from dht libraray\n  if (isnan(humidity) || isnan(temperature))\n  {\n    Serial.println("Error while parse values to numbers from dht");\n    drawMessage("Errir reading DHT");\n    delay(2000);\n  }\n\n  client.publish(TEMPERATURE_TOPIC, String(temperature).c_str()); \/\/ Publish temperature to the temperature value topic\n  client.publish(HUMIDITY_TOPIC, String(humidity).c_str());       \/\/ Publish humidity to the humidity value topic\n  Serial.print("Temp:");\n  Serial.println(temperature);\n  Serial.print("Displayconnected:");\n  Serial.println(displayconnected);\n  Serial.print("Prev:");\n  Serial.println(prevmeter);\n  Serial.print("Reading2:");\n  Serial.println(reading);\n    Serial.print("Screentimeout:");\n    Serial.println(screentimeout);\n\n  if (displayconnected)\n  {\n    if ((reading < (prevmeter - 0.1)) || (reading > (prevmeter + 0.1)) ||(prevmeter == 1000))\n    {\n      prevmeter = reading;\n      screentimeout = 10;\n    }\n          screentimeout--;\n      if (screentimeout < 1)\n      {\n        screentimeout = 1;\n        screenoff();\n      }\n    Serial.print("Minvalue:");\n    Serial.println((prevmeter - 0.1));\n   \n    if (screentimeout > 1)\n    {\n      Serial.println("Print to display");\n      drawText(temperature, reading, humidity, "beer remaining !!!");\n    }\n  }\n}\n\nvoid reconnect()\n{\n  while (!client.connected())\n  { \/\/ Loop until connected to MQTT server\n    Serial.print("Attempting MQTT connection...");\n    if (client.connect(HOSTNAME, mqtt_username, mqtt_password))\n    { \/\/ Connect to MQTT server\n      Serial.println("connected");\n      client.publish(AVAILABILITY_TOPIC, "online"); \/\/ Once connected, publish online to the availability topic\n      client.subscribe(TARE_TOPIC);                 \/\/ Subscribe to tare topic for remote tare\n      client.subscribe(OFFSET_TOPIC);\n    }\n    else\n    {\n      Serial.print("failed, rc=");\n      Serial.print(client.state());\n      Serial.println(" try again in 5 seconds");\n      delay(5000); \/\/ Will attempt connection again in 5 seconds\n    }\n  }\n}\n\nvoid callback(char *topic, byte *payload, unsigned int length)\n{\n  if (strcmp(topic, TARE_TOPIC) == 0)\n  {\n    Serial.println("starting tare...");\n    scale.wait_ready();\n    scale.set_scale();\n    scale.tare(); \/\/ Reset scale to zero\n    Serial.println("Scale reset to zero");\n  }\n  if (strcmp(topic, OFFSET_TOPIC) == 0)\n  {\n    Serial.println("Setting offset...");\n    scale.wait_ready();\n    scale.set_scale();\n    scale.set_offset(offset_factor);\n    Serial.print("Scale set to offset ");\n    Serial.println(*payload);\n  }\n}\nvoid drawText(float temperature, float volume, float humidity, String message)\n{\n  display.clearDisplay();\n  display.setCursor(0, 0); \/\/ Start at top-left corner\n  display.setTextSize(1);  \/\/ Draw 2X-scale text\n  display.setTextColor(SSD1306_WHITE);\n  display.print("T: ");\n  display.print(temperature);\n  display.print((char)247);\n  display.println(F("C"));\n  display.print("H: ");\n  display.print(humidity);\n  display.println(F("%"));\n  display.setTextSize(3); \/\/ Draw 2X-scale text\n  display.print(volume);\n  display.println(F("L"));\n  display.setTextSize(1); \/\/ Draw 2X-scale text\n  display.println(message);\n\n  display.display();\n  \/\/ delay(2000);\n}\nvoid drawMessage(String message)\n{\n  display.clearDisplay();\n  display.setCursor(0, 0); \/\/ Start at top-left corner\n  display.setTextSize(1);  \/\/ Draw 2X-scale text\n  display.setTextColor(SSD1306_WHITE);\n  display.println(message);\n  display.display();\n  \/\/ delay(2000);\n}\n\nvoid screenoff()\n{\n  display.clearDisplay();\n  display.display();\n}\n\n<\/pre><\/div>\n\n\n
File : config.h<\/p>\n\n\n
\n\/\/ Wifi Settings\n#define SSID                          "SSID"\n#define PASSWORD                      "WIFIPWD"\n\n\/\/ MQTT Settings\n#define HOSTNAME                      "HA hostname" \/\/"beer_1"\n#define MQTT_SERVER                   "192.168.10.132"\n#define STATE_TOPIC                   "beer_1"\n#define STATE_RAW_TOPIC               "beer_1\/raw"\n#define AVAILABILITY_TOPIC            "beer_1\/available"\n#define TARE_TOPIC                    "beer_1\/tare"\n#define OFFSET_TOPIC                  "beer_1\/offset"\n#define TEMPERATURE_TOPIC             "beer_1\/temperature"\n#define HUMIDITY_TOPIC                "beer_1\/humidity"\n#define mqtt_username                 "mqttusername"\n#define mqtt_password                 "mqttpassword"\n\n\/\/ HX711 Pins\nconst int LOADCELL_DOUT_PIN = 12;  \/\/ Remember these are ESP GPIO pins, they are not the physical pins on the board.\nconst int LOADCELL_SCK_PIN = 13;\nint calibration_factor = -22500;  \/\/ Defines calibration factor we'll use for calibrating.\nint offset_factor = -285746;       \/\/ Defines offset factor ; -285746 = Empty Cornelius 19L keg. \n\n\/\/ DHT Settings\nconstexpr auto DHT_PIN = 14;            \/\/ Remember these are ESP GPIO pins, they are not the physical pins on the board. \n#define DHT_TYPE DHT11                 \/\/ DHT11 or DHT22\nconstexpr auto sendDHTDataDelay = 500ul; \/\/ Delay between sending data over MQTT\n\n<\/pre><\/div>","protected":false},"excerpt":{"rendered":"
Since Plaato is retiring their Keg scale in 2024\/25 I had to find a new solution. Searching the web lead me to GitHub – Callwater\/Beerkeg-load-cell. Since I had some ESP and loadcells at my hands it was very quick to setup. Had some wood and a router in my ‘workshop’ so made the base in … Continue reading My ‘simple’ keg scale<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[1],"tags":[],"class_list":["post-1238","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t