Emoncms Clients for Home Energy Monitoring

EmonCMS

EmonCMS is a powerful open-source web-app for processing, logging and visualising energy, temperature and other environmental data. This can be used to monitor the current consumption for your home using simple components.

Particle Photon

Photon is an tiny WiFi enablet IoT device made natively to be connected to the Particle.io device cloud. These units can be programmed, monitored and managed through the Particle.io DeviceCloud.

NodeMCU

NoeMCU is an open source IoT platform. It includes firmware which runs on the ESP8266 Wi-Fi SoC from Espressif Systems, and hardware which is based on the ESP-12 module. The term "NodeMCU" by default refers to the firmware rather than the dev kits. The NodeMCU is ment to be used with the eLua project, but can also be programmed with the Arduino IDE Environment with a few adjustments. See the Sparkfun ESP8266 Thing Hookup Guide for details.

TSL250

The TSL250R-LF is an optical light to voltage sensor that signals if there is light present or not. This will be used for triggering interrupts in the NodeMCU, and count the timing between the 1000pulses/KWh on the home power central.

Connections and Interrupt handling

The TSL250R-LF is connected to the 3.3V, GND and D1 terminals. The D1 connector is then setup for interrupt handling.

NodeMCU

  // Attach interupt for capturing light pulses on powercentral
  attachInterrupt(digitalPinToInterrupt(D1), onPulse, FALLING);

Note that GPIO0, GPIO2, GPIO6-11 and GPIO15 has dual meaning on the ESP module, and might affect startup, or operating mode of the module. Using D1 - GPIO5 in this project to avoid the problem all toghether. Started using D4 (GPIO2), but this affected bootup, and flashing, so if there was a powerfailure or reset the device would not boot. For more info search the web.

Photon

  // Attach interupt for capturing light pulses on powercentral
  attachInterrupt(D1, &onPulse, FALLING);

Interrupt filtering

For avoiding ripple in the interrupt triggering, and getting false readings there is made a small time validation in the onPulse() method

// The interrupt routine - runs each time a falling edge of a pulse is detected
void onPulse()                  
{
  unsigned long elapsedTime = micros() - pulseTime;
  if (elapsedTime >= MIN_ELAPSED_TIME)  //in range
  {      
    pulseTime = micros();       //used to measure time between pulses.
    // Put time calculations between interrupts here

EmonCMS Clients

HTTP Client

The HTTP client made uses the EmonCMS HTTP API, with the private API_WRITE_KEY from your EmonCMS account to update the values.

This client was made to run on the NodeMCU device

Particle Client

The Particle client uses the Particel DeviceCloud with WebHooks set up to talk to the EmonCMS HTTP API. The Webbhook must be set up using the private API_WRITE_KEY from your EmonCMS account

This client was made to run on the Particle Photon device

EmonCMS.org

Example for monitoing data representation on emoncms.org

Hosting your own EmonCms

For hosting your own local EmonCms instance, see my EmonCms Docker Project. This wrapps the official EmonCms docker relase with Let`s Encrypt and Nginx.

Secrets.h

In the .gitignore file there is put a file called Secrets.h. This is a .h file ment to keep passwords and other connection details like the emoncms API_WRITE_KEY. This will not be added to the git repository, but must be present alongside the .ino files to make the sketch compile. Here is an example on what this file can look like:

#ifndef SECRETS
#define SECRETS

// Define Secrets
#define API_KEY "1232343465dfgegergegrerg"
#define WIFI_SSID "ssid_wifi_name"
#define WIFI_PASSWORD "ssid_wifi_password"

#endif

*This file is only needed for NodeMCU devices, and not Photon devices, since the Photon should be set up with the correct WiFi settings in memory, and will use these to connect.