WRL-13804 Sparkfun ESP8266 Thing Dev Board from Core Electronics. Some are shown here if you prefer a more expanded pin selection and more room to work.ĪDA2471 Adafruit HUZZAH ESP8266 Breakout from Core Electronics. When building this project, you could of course use your own variant of ESP8266 microcontroller boards. The only real setup required for this chip is soldering on its header pins, which are included with the board. The weapon of choice is the WiFi Mini from Jaycar, a very compact microcontroller board built around the ESP8266. Since the focus of this project is not on the electronics and rather on the software that controls our overall IoT system, we have chosen not to build our own circuit based on the ESP8266 and have instead chosen a pre-built board that includes everything we need. If you have done anything with IoT before, you will no doubt heard of this little monster! It packs a capable microcontroller, GPIO pins, WiFi connectivity and compatibility with Arduino code into a package no bigger than an Aussie 20-cent coin. WiFi MicrocontrollerĪt the heart of our LED display is the ESP8266 microcontroller. Likewise, recording videos near the display can generate flickering in the video because of the difference in shutter speed to the LED multiplexing rate – keep this in mind if you plan to record videos. The downside of multiplexing in this way is that because LEDs are turned quickly on and off over time, it can create a jittery and slightly uncomfortable viewing experience if the LEDs are moved around. It is possible to trick the human eye into believing all LEDs are lit simultaneously if the multiplexing process is done fast enough – similar to how old CRT screens draw a scanline across the screen 60 times per second to create an illusion of a solid image. The next row is then enabled, and the process repeats. By applying a voltage to all LEDs within a row and then controlling which LEDs can sink current, a specific combination of LEDs can be lit. It is difficult to individually control large banks of LEDs by independently controlling the sources and sinks of each. LEDs, to light, need to have both a current source and a location to “sink” current to ground – in other, words, a complete circuit. This technique of driving large LED matrices has been explained in detail before in DIYODE, but here is a refresher if you’re curious! The matrix includes a AIP1640 chip capable of driving 16 columns of 8 segments, by multiplexing between each row and column. You should only be drawing less than half an amp of current at the most through a standard USB computer port before a dedicated 5V power supply should be used! Multiplexing the displayĪs a side note, using 128 microcontroller pins for driving one LED each is incredibly inefficient. Note that as you increase the size and therefore required power of your displays, you will need an appropriately powerful 5V supply to match the LED display. Here is Jaycar’s 32x16 large LED matrix, which could be used as a wall-mount IoT Display! Of course, there are countless other LED displays that you could use for this project. XC4623 Blue LED Dot Matrix Display for Arduino from Jaycar. XC3746 8x16 LED Matrix with I2C connection. We just need to feed in a I2C connection from our microcontroller and interface with it in code. We do not need to worry about the specifics of driving the display, since the AIP1640 chip mounted on the back of the board takes care of it for us. In terms of controlling this display, it’s very simple. While the display is quite small at only 72mm by 32mm, its the perfect size for a desk gadget that can provide periodical data updates. 128 LEDs is enough to display alphanumeric characters, making it perfect for a simple yet effective IoT-connected display. The LED Display we have chosen for this project is Jaycar’s 8x16 single-colour LED matrix. Let’s get into it! HOW IT WORKS LED Display The focus of this project is on the software itself, but both the electronics and software can be expanded to build functionality for your own DIY electronics gadgets. The electronics for this project is very simple, consisting of only a LED matrix and an ESP8266 module. This project will be a simple but highly expandable peek into the world of Internet Of Things, building our own IoT device with our own API calls and user interface! We’ll provide an introduction to how you can build your own streams of data from webservers, whether they are publicly available on the internet or sourced from your own devices. Last month, we looked at the Arduino MKR NB 1500 and it’s awesome power to unite the versatility of Arduino with the widespread coverage of Telstra networks. Internet Of Things, as the name implies, is a common description of combining software-driven data and control with hardware-based interfaces.
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