{"id":190,"date":"2018-10-16T02:42:50","date_gmt":"2018-10-16T02:42:50","guid":{"rendered":"https:\/\/www.appservgrid.com\/paw93\/index.php\/2018\/10\/16\/create-an-iot-sensor-with-nodemcu-and-lua\/"},"modified":"2018-10-16T03:15:03","modified_gmt":"2018-10-16T03:15:03","slug":"create-an-iot-sensor-with-nodemcu-and-lua","status":"publish","type":"post","link":"https:\/\/www.appservgrid.com\/paw93\/index.php\/2018\/10\/16\/create-an-iot-sensor-with-nodemcu-and-lua\/","title":{"rendered":"Create an IoT sensor with NodeMCU and Lua"},"content":{"rendered":"

In this post I want to show you how to create your own IoT sensor with the NodeMCU and the Lua programming language. The device called the NodeMCU makes it easy to start reading sensor data, sending it back to another location for processing or aggregation, such as the cloud. We’ll also compare the NodeMCU to the Raspberry Pi and talk about the pros\/cons of each for an IoT sensor.<\/p>\n

Introduction<\/h2>\n

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Picture Wikipedia<\/a> Creative Commons<\/p><\/blockquote>\n

NodeMCU 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.<\/p><\/blockquote>\n

via Wikipedia<\/a><\/p>\n

The device looks similar to an Arduino or Raspberry Pi Zero featuring a USB port for power or programming and features a dedicated chip for communicating over WiFi. Several firmwares are available (similar to an Operating System) for programming the device in Lua, C (with the Arduino IDE) or even MicroPython<\/a>. Cursory reading showed the Lua firmware to support the most amount of modules\/functionality including HTTP, MQTT and popular sensors such as the BME280.<\/p>\n

The documentation for the NodeMCU<\/a> with Lua is detailed and thorough giving good examples and I found it easy to work with. In my opinion the Lua language feels similar to Node.js, but may take some getting used to. Fortunately it’s easy to install Lua locally<\/a> to learn about flow control, loops, functions and other constructs.<\/p>\n

NodeMCU vs Raspberry Pi<\/h3>\n

The Raspberry Pi Zero runs a whole Operating System which is usually Linux and is capable of acting as a desktop PC, but the NodeMCU runs a firmware with a much more limited remit. A Raspberry Pi Zero can be a good basis for an IoT sensor, but also is rather over-qualified for the task. The possibilities it brings come at a cost, such as relatively high power consumption and unreliable flash storage, which can become corrupted over time.<\/p>\n

Its power consumption with WiFi<\/a> enabled could be anything up to 120 mA even with HDMI and LEDs disabled. In contrast the NodeMCU runs a much more specialised chip with power-saving features such as a deep sleep mode that can make the board run for up to a year with a standard 2500mAh LiPo battery<\/a>.<\/p>\n

Here’s my take:<\/p>\n

I’m a big fan of the Raspberry Pi and own more than anyone else I know (maybe you have more?), but it does need maintenance such as OS upgrades, package updates and the configuration to set up I2c or similar can be time-consuming. For IoT sensors, if you are willing to learn some Lua the NodeMCU can send readings over HTTP or MQTT and is low-powered and low hassle at the same time.<\/p><\/blockquote>\n

If you already have a Raspberry Pi and can’t wait to get your NodeMCU then you can follow my tutorial with InfluxDB here<\/a>.<\/p>\n

yep, saw your @pimoroni<\/a> EnviroPhat piece and thought it was Grafana to start with-this is my version pic.twitter.com\/YlRjuLMfBk<\/a><\/p>\n

\u2014 Alex Ellis (@alexellisuk) 2 September 2016<\/a><\/p><\/blockquote>\n

Tutorial overview<\/h2>\n