Bitcoin is an online currency which uses peer-to-peer technology for payment transfers. Its price is varying over time and if you have some investments in Bitcoins, you should keep an eye on it. Rui Santos suggests using ESP8266 programmable WiFi module to check Bitcoin price. The idea is pretty simple. He programmed WiFi module as HTTP client which regularly requests Bitcoin price by using JSON API.
ESP8266 is fairly to program. All you need is to flash it with NodeMCU firmware which then allows programming module with LUA script which is somewhat similar to Arduino concept. With only few lines of code you can connect to internet, control GPIO and do other crazy things. This following script can be used as base for other HTTP client projects like weather, finances or other extraction.
ESP8266 is really cheap (~$4) WiFi transceiver module that comes in many PCB configurations. WiFi module can be connected to other devices that can access and control it with AT commands, but fun part is that WiFi module can be used as stand alone device which can be programmed with LUA script which could perform simple tasks like connect to WiFi, control GPIOs and toggle LEDs or drive other devices.
Rui Santos have written a nice tutorial where he teaches how to set up a schematic of two LEDs connected to ESP8266 module. Then he demonstrates how to write a simple LUA script using ESPlorer Java based GUI and how to flash device with NodeMCU flasher. His example script enables WiFI module to work as web server where you can access it through web page and turn ON/OFF two LEDs by simply pressing buttons.
When working with power devices it is always good to know what is going on. Especially this is important when experimenting with unknown parameter devices like motors, inductors or batteries. Dorkbotpdx shared a power playground that would allow to run different things and have full control and feedback of process.
He used PMOS/NMOS H-Bridge configuration attached to Teensy-3.1 microcontroller board which runs FreeRTOS. There is a current sensor next to bridge which helps on experiments with PWM motor control, power line synchronization, battery charging/discharging. Four digit 7-segment LED indicator gives a simple visual feedback. This is a great tool for many interesting experiments.
If you are running website on a server you know that many things can happen. It can go down due several reasons and you may notice this only when try to connect or load webpage. In order to avoid long downtimes you need to set up alarm which would ring bells and whistles once it goes down. Kelsey shared a website down alarm project based on Tessel board.
Tessel board simply pings website every second and once trouble is detected it starts alarm which is a large red alarm light. Lamp was modified to be controlled from relay module which plugs directly to Tessel board. Speaking of Tessel boar it is an ARM processor based development board which runs entirely on Node.js. It already has built in WiFi module what makes it great tool for Internet of Things (IoT).