MQTT
IoT switch using relay operated by micropython based NodeMCU
IoT is gaining market rapidly. In recent years, many appliance, automobile manufactures have started adding “connected” features in their product line. Most basic IoT implementation you can think of is, switching on|off an appliance over internet. Let us see how this works and how you can build a IoT switch under 7 USD. You need […]
Multi topic IoT subscriber model
In a typical IoT model, you have many IoT sensors publishing data to IoT broker. You may want to collect data from all these IoT nodes in a database for visualization and further analytics. I have couple of IoT nodes installed in two houses in two different cities. And I collect data from all IoT […]
Air quality monitor using GP2Y1010AU0F sensor on micropython based NodeMCU
I had purchased GP2Y1010AU0F sensor about 6 months back. Finally, found time to hook it with NodeMCU controller. Firstly, let me list things you need. NodeMCU (ESP8266) controller (~300₹). GP2Y1010AU0F dust/smoke sensor(~450₹). 150k ohm resistor. 220 µF capacitor. breadboard with some connecting wires. Here is the connection schema of circuit. Since solution is based on […]
Transmit weather stats from DHT22 using MQTT on micropython
In my previous article about DHT22 sensor, I had used arduino based programming to collect and transmit weather stats over MQTT. But that time I was wondering, how can I make it flexible by having WiFi, sensor and MQTT parameters configurable. Now, with micropython, I can prepare a simple json config file having all parameters […]
Publish IoT messages from micropython based client
Micropython is quite capable firmware to build prototypes and do experiments. Paired with ESP8266 micro controller board, it builds a perfect IoT client, which can be further interfaced with variety of sensors, motors, relays etc. Fundamental of IoT is data collection from sensors and connected IoT nodes. You can also establish machine to machine communication […]
Publish IoT data in Influxdb and visualize in Grafana
I had build an IoT enabled weather station. Now let us build a nice platform to store time series data coming out of DTH22 (weather sensor) on NodeMCU and visualize it into Grafana. I have installed and configured influxdb and Grafana onto my raspberry pi which also hosts my MQTT broker. Weather station code transmits […]
Monitoring aquarium temperature using DS18B20
I have a aquarium with two parrot fishes and few other species. Parrot fishes live happily within 25 to 32 degree Celsius. If temperature goes out of limits then it effects metabolism and behavior of fishes. Even though aquarium heater has thermostat I thought to observe temperature and record it over time. For this you […]
IoT enabled Smart doorbell
How useful would it be if you are notified on phone with the photo of visitor on door moment doorbell rings 🙂 Let us build a low cost and simple solution without intercepting anything on 220v supply of doorbell. Things you need 1) NodeMCU board. 2) sound sensor with digital output(it a simple mic hooked […]
Reliable machine to machine communication using MQTT QoS
MQTT messaging provides three levels of quality of service. Depending upon the requirement QoS levels can be selected for various services. QoS level 0 This is the default QoS level when QoS is not explicitly set. This is simplest form of MQTT message where client publishes the message to broker and there is no acknowledgment […]
IoT ready relay to operate 220v AC home appliances
When I am away from home during long vacations I felt need of having control of some lights back at home, specially during Diwali holidays to turn on lights at night. I had already interfaced my 4 channel relay with raspberry and NodeMCU and control it via ssh terminal on raspberry and serial port of […]