Representational state transfer (REST) is a software architecture that is widely used for web applications. In this project, we'll bring this architecture to Arduino so you can control an Arduino board via WiFi using a standard communication scheme. This way, you won't have to start from scratch at every new project and you'll be able to create complex wireless applications!
This cyber-tronic looking sensor hides a secret behind it's glimmering eye. Unlike most temperature sensors, this sensor measures infrared light bouncing off of remote objects so it can sense temperature without having to touch them physically. Simply point the sensor towards what you want to measure and it will detect the temperature by absorbing IR waves emitted. Because it doesn't have to touch the object it's measuring, it can sense a wider range of temperatures than most digital sensors: from -70°C to +138°C It takes the measurement over an 90-degree field of view so it can be handy for determining the average temperature of an area.
Your microcontroller probably has an ADC (analog -> digital converter) but does it have a DAC (digital -> analog converter)??? Now it can! This breakout board features the easy-to-use MCP4725 12-bit DAC. Control it via I2C and send it the value you want it to output, and the VOUT pin will have it. Great for audio / analog projects, such as when you can't use PWM but need a sine wave or adjustable bias point.
If you want to take your project portable you'll need a battery pack! For beginners, we suggest alkaline batteries, such as the venerable AA or 9V cell, great for making into larger multi-battery packs, easy to find and carry plenty of charge. If you want to go rechargable to save money and avoid waste, NiMH batteries can often replace alkalines. Eventually, however you may want to upgrade to the shiniest new technology - rechargable lithium ion/polymer batteries. In this guide you will learn all about these batteries, and how to properly use them in your projects.
A power supply is a device that supplies power to another device, at a specific voltage level, voltage type and current level. While it sounds simple, power supplies have a lot of little hang-ups that can be very tricky for the uninitiated. This tutorial will try to help explain all about power supplies.
Thermocouples are best used for measuring temperatures that can go above 100 degC. This is a bare wires bead-probe which can measure air or surface temperatures. Most inexpensive thermocouples have a vinyl covering which can melt at around 200 degC, this one uses a fiberglass braid so it can be used in high temperature measurements such as heaters and ovens. This is a handy guide which covers thermocouple use including an Arduino library and example code.
A thermistor is a thermal resistor - a resistor that changes its resistance with temperature. Technically, all resistors are thermistors - their resistance changes slightly with temperature - but the change is usually very very small and difficult to measure. Thermistors are made so that the resistance changes drastically with temperature so that it can be 100 ohms or more of change per degree! This guide will teach you how thermistors work, and how to wire them up and use them with your favorite microcontroller.