We live in great times. There was once a day when the only way to determine if the cat feeder needed more kibble was to actually look at it with your own eyes like some Neanderthal. Thankfully technology and the magical world of IoT has changed all of that.
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For this project we use a WiFi enable ESP8266 and a STMicro VL53L0X ToF Sensor mounted to a breakout board. If you don't find a need to measure feline food consumption the project still provides Arduino code that can be extremely useful for your other IoT projects:
- Logging data to a Google Drive Spreadsheet (via IFTTT)
- Logging data to AT&T's M2X machine to machine servers (think nice graphs)
- Sending SMSs to your mobile device (via IFTTT)
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What's happening?
The ESP8266 runs in Arduino mode (source code below) in an endless loop. Every hour it polls the VL53L0X ToF Sensor mounted on the lid of the cat food feeder.
Since we know how many centimeters the food is from the ToF sensor at full and at empty we are able to scale those values and report/log "percent full" status. Those values are posted to a Google Drive Spreadsheet and to AT&T's M2X machine to machine servers for logging. If the food level is considered CRITICALLY LOW a SMS message goes out to our mobile device. Just to increase the geek factor, CRITICALLY LOW alerts are also displayed on our Pebble watch.
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The Google Drive Spreadsheet looks like this:
Here is the bad ass AT&T M2X machine to machine server graph (note the increase after we filled the feeder):
The IFTTT SMS alerts are sent if the rig determines food levels critically low:
So..... How's it done? You will need these:
- WiFi enable ESP8266
- STMicro VL53L0X ToF Sensor mounted to a breakout board
- Some wire and a breadboard.
Mount it to the cat feeder and you end up with this:
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Now all that is left is to copy/paste the code below into the Arduino IDE. Upload it to the ESP8266 and your cats will never go hungry again!
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/*
* AUG2017
* STMicro VL53L0X ToF Sensor for
* Cat Food Level Monitoring
* WhiskeyTangoHotel.Com
*
* Logs % full values to:
* Google Drive (as an appending spreadsheet)
* AT&T M2X for historical graphing
* Send SMS to cell phone if level condition is RED/CRITICAL
*
* uC setting for Ardunio IDE
* NoderMCU 1.0 (ESP-12E Module), 80MHz, 921600, 4M (3M SPIFFS)
*
*/
// For the STMicro VL53L0X ToF Sensor
// I2C SDA to ESP8266 Pin D2. SCL to ESP8266 Pin D1
#include "Adafruit_VL53L0X.h" // Thanks again ADAFRUIT!!!
Adafruit_VL53L0X lox = Adafruit_VL53L0X();
// For the Wireless
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <ESP8266mDNS.h>
// WiFi Connection Information
const char* ssid = "YourNetworkHere"; // PRIVATE: Enter your personal setup information.
const char* password = "YourNetworkPasswordHere"; // PRIVATE: Enter your personal setup information.
ESP8266WebServer server(80);
// IFTTT Information for WebHook widget
String MAKER_SECRET_KEY = "YourIFTTTCodeHere"; // PRIVATE: Enter your personal setup information. Your IFTTT Webhook key here
String TRIGGER_NAME_google_drive = "Cat_Food"; // this is the Maker IFTTT trigger name for google drive spreadsheet logging
String TRIGGER_NAME_M2X = "cat_food_mx"; // this is the Maker IFTTT trigger name for M2X logging
String TRIGGER_NAME_SMS = "CriticalFoodLevel_SMS"; // this is the Maker IFTTT trigger name to send SMS if low is level is CRITICAL.
const char* host = "maker.ifttt.com";
String url_google_drive; // url that gets built for the IFTTT Webhook logging to google drive spreadsheet
String url_M2X; // url that gets built for the IFTTT Webhook logging to AT&T M2X service
String url_SMS; // url that gets built for the IFTTT Webhook sending SMS if food level is critical
// Define and set up some variables
float Range_inches; // How far the sensor is from the food at time of reading. Sensor is on roof of feeder.
float Min_level = 5.0; // Distance in inches before low food alarm level. Food is far from sensor on feeder roof
float Max_level = 0.5; // Distance in inches from sensor for full feeder level. Food is close to sensor on feeder roof
float Percent_full; // How full in xx.x% is the food based on the Min/Max_levels defined above
float Caution_alarm = 35.0; // at xx.x% food level is considered low. String Status YELLOW
float Critical_alarm = 25.0; // at xx.x% food level is considered critically low. String Status RED
String Status = "***_Starting_with_Caution_at:_" + String(Caution_alarm) + "%_and_CRITICAL_at:_" + String(Critical_alarm) + "%"; // Update to Out of Range, NORMAL, LOW, CRITICAL, etc. "spaces" will error IFTTT Webhook; use "_"
int Run_number; // how many times the sensor has been read
// Output pins
const int led = 2; // Blue on board LED is on PIN2 for this NoderMCU 1.0 ESP8266. Blink it between reads
// Program control variables
int Seconds_between_posts = 60 * 60; // how often to post the results of the sensor read. NOT EXACT due to post delays, Sensor reads, LED flashing, etc.
int logging = 1; // If 1 then log to cloud. Any other value (0) turns it off. ESP8266 "Start/Restart" message is always logged.
void setup(void){ // This is run once.
pinMode(led, OUTPUT); // set up the onbaord LED pin as an output.
Serial.begin(115200); // turn on the serial monitor for debug
// wait until serial port opens for native USB devices
while (! Serial) {
delay(1);
}
// Is the ToF sensor connecting via I2C?
Serial.println("STMicro VL53L0X test");
if (!lox.begin()) {
Serial.println(F("Failed to boot VL53L0X!!!"));
while(1);
}
// power
Serial.println(F("VL53L0X Passed... \n\n"));
// Is the WiFi working?
WiFi.begin(ssid, password);
Serial.println("");
// Wait for connection
while (WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.print("Trying to connect to ");
Serial.print(ssid);
Serial.print(" on ");
Serial.print(WiFi.localIP());
Serial.println(".");
}
Serial.print("Connected to ");
Serial.println(ssid);
Serial.println(WiFi.localIP());
if (MDNS.begin("esp8266")) {
Serial.println("MDNS responder started");
Serial.println(" ");
}
// Use WiFiClient class to create TCP connections for WiFi logging
WiFiClient client;
const int httpPort = 80;
if (!client.connect(host, httpPort)) {
Serial.println("connection failed"); // Boo!!!
return;
}
server.begin();
Serial.println("HTTP server started"); // Woo Hoo!!!
// Write to Google Sheet via IFTTT Maker channel that the ESP8266 has started/restarted
// Trigger the IFTTT Webhook Channel to update a Google sheet with the activity of the server starting/restarting
// This can help log power outs, etc. For first run we defined String Status for identify a startup condition.
// Create the request for IFTTT google drive
url_google_drive = "https://maker.ifttt.com/trigger/" + TRIGGER_NAME_google_drive + "/with/key/" + MAKER_SECRET_KEY + "?value1=" + String(Status);
Serial.println("Status: " + Status);
Serial.println(" ");
// This sends the request to the IFTTT server
client.print(String("POST ") + url_google_drive + " HTTP/1.1\r\n" +
"Host: " + host + "\r\n" +
"Connection: close\r\n\r\n");
delay(500); // Delay for web traffic; maybe not required.
}
void loop(void){
// Loop forever. Read the sensor and post based on the delay values set above.
// The blue onboard LED will blink between ToF reads.
// Read the ToF. Distance in mm returned.
for (int x = 0; x < 10; x++) { // Quick toggle blue on board LED to show measurement being taken.
digitalWrite(led, !digitalRead(led)); // toggle state of the on board blue LED. Shows program is running
delay(100); } // endfor quick toogle Blue LED
VL53L0X_RangingMeasurementData_t measure;
Serial.println("-------------------------------------");
Serial.println("Reading a measurement... ");
lox.rangingTest(&measure, false);
// Convert to inches because the USA, for some reason, doesn't want to adopt the metric system...
Range_inches = measure.RangeMilliMeter/25.4;
Run_number = Run_number + 1;
// Scale and normalize the Min Max levels to 0% to 100%. Clip the range in case of a the Max fill limit was exceeded or a misread.
Percent_full = ((Range_inches - Min_level) / (Max_level - Min_level)) * 100.0;
if (Percent_full > 100) {
Percent_full = 100.00;
}
if (Percent_full < 0) {
Percent_full = 0.0;
}
//Serial.println(String(Range_inches)); // Debug use
// Is the ToF Sensor reading 'anything' for a distance?
if (Range_inches > 100 ) { // Something's weird. Ranging error. The ToF sensor is NOT over 100 inches fron the food. EVER!!!
Status = "Run:" + String(Run_number) + "__ERROR:_***_Out_of_Range_***";
} else { // ToF made a successful reading so log the food level
if (Percent_full >= Caution_alarm) { // above CAUTION LEVEL, All's good
Status = "Run:" + String(Run_number) + "___GREEN---GOOD";
} // endif GREEN---GOOD
if (Percent_full < Caution_alarm && Percent_full > Critical_alarm) { // CAUTION Zone, YELLOW---REFILL_SOON
Status = "Run:" + String(Run_number) + "___~~~YELLOW---REFILL_SOON~~~";
} // end if YELLOW---REFILL_SOON"
if (Percent_full <= Critical_alarm) { // CAUTION Zone, RED---REFILL_ASAP"
Status = "Run:" + String(Run_number)+ "___!!!_RED---REFILL_ASAP_!!!";
if (logging == 1) { // is logging turned on? Maninly for debug... Typically would be set = 1
// Set up IFTTT Webhook Channel to send the SMS.
// Use WiFiClient class to create TCP connections for IFTT SMS
WiFiClient client;
const int httpPort = 80;
if (!client.connect(host, httpPort)) {
Serial.println("connection failed");
return;
}
url_SMS = "https://maker.ifttt.com/trigger/" + TRIGGER_NAME_SMS + "/with/key/" + MAKER_SECRET_KEY+ "?value1=" + String(Percent_full);
Serial.println("Critical Level: Sending SMS with payload:.");
Serial.println(url_SMS);
Serial.println(" ");
client.print(String("POST ") + url_SMS + " HTTP/1.1\r\n" +
"Host: " + host + "\r\n" +
"Connection: close\r\n\r\n");
//Serial.println("GOOGLE DRIVE URL:");
//Serial.println(url_google_drive);
delay(500); // pause for webservices
}
} // endif RED---REFILL_ASAP
}
// Serial print to the monitor for debug
Serial.println(String(Range_inches) + " inches down / " + String(Percent_full) + "% full");
Serial.println("Status: " + Status);
// Create the request for IFTTT Google Drive and M2X updates
url_google_drive = "https://maker.ifttt.com/trigger/" + TRIGGER_NAME_google_drive + "/with/key/" + MAKER_SECRET_KEY + "?value1=" + String(Percent_full) + "%" + "&value2=" + Status;
url_M2X = "https://maker.ifttt.com/trigger/" + TRIGGER_NAME_M2X + "/with/key/" + MAKER_SECRET_KEY + "?value1=" + String(Percent_full);
// This sends the request to the IFTTT server.
//Serial.println("Requesting URL..."); // debug
//Serial.println(url); // debug
if (logging == 1) { // is logging turned on? Maninly for debug... Typically would be set = 1
//Serial.println("Logging is ON.");
// Set up IFTTT Webhook Channel to update a Google sheet with the activity.
// Use WiFiClient class to create TCP connections for IFTT Webhook logging
WiFiClient client;
const int httpPort = 80;
if (!client.connect(host, httpPort)) {
Serial.println("connection failed");
return;
}
client.print(String("POST ") + url_google_drive + " HTTP/1.1\r\n" +
"Host: " + host + "\r\n" +
"Connection: close\r\n\r\n");
Serial.println(" ");
Serial.println("IFTTT url payload to Google Drive:");
Serial.println(url_google_drive);
Serial.println(" ");
delay(500); // pause for webservices
// Set up IFTTT Maker Channel to update a AT&T M2X Server with the activity.
// Use WiFiClient class to create TCP connections for IFTT Webhook logging
//WiFiClient client;
//const int httpPort = 80;
if (!client.connect(host, httpPort)) {
Serial.println("connection failed");
return; }
client.print(String("POST ") + url_M2X + " HTTP/1.1\r\n" +
"Host: " + host + "\r\n" +
"Connection: close\r\n\r\n");
Serial.println("IFTTT url payload for M2X:");
Serial.println(url_M2X);
} else {
Serial.println("Logging is OFF.");
} // endif/else logging
for (int x = 0; x < Seconds_between_posts; x++) { // Delay for next measurement.
digitalWrite(led, !digitalRead(led)); // toggle state of the on board blue LED. Shows program is running
delay(1000); } // endfor delay for read measurement
}
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