Introducing: ChipSnip Sensors
Your ChipSnip kit contains a set of sensors. The sensors below produce an analog signal that changes in amplitude based on an external stimulus.
What is an analog signal? You probably look at an analog signal indicator every day, especially if you use a modern cell or smart phone. The indicators for cell and WIFI-signal contain bars that tell how strong your signal is. The higher the number of bars lit up, the higher the signal from your nearest cell tower or indoor WIFI router. Another indicator, for your battery, tells us how strong the battery's electric potential is, typically as a percentage of its maximum or "full" level. Analog signals have a range of values that can be measured to any level of precision, only limited by your sensing equipment.
The force sensor produces an analog output proportional to the amount of force applied to the round end of the sensor.
Reflective Infrared (IR)
The Reflective IR sensor has an infrared emitter on the left (by the socket) and the IR detector itself on the right. An object close to the IR emitter/detector will reflect infrared light from the emitter into the detector. It can sense short distances between an object and the sensor.
Be careful using this sensor, infrared light is emitted by many, especially incandescent, light systems and the sun. Expect ambient infrared light to be a component of the analog signal along with anything reflected off the IR emitter. Also different materials reflect IR light differently. A white sheet of paper will reflect IR light very well, but black denim will barely reflect any IR light at all.
Also called an "accelerometer", this sensor can help you measure the amount of acceleration placed on it. Acceleration due to gravity will always be present and this senor can give you an idea of how it is positioned relative to the ground. It can also help you know if something is moves or bumps the sensor or anything it is attached to. Smart phones and tablets use these to rotate your screen or determine picture orientation and such.
This little sensor indicates the intensity of light shining down upon it. It is useful for measuring the ambient light in the room or detecting if something is uncovered. Sensors like these are often used to adjust display lighting so it's not too bright at night or too dim during the day.
This sensor provides an output proportional to the temperature of the thermistor in the center of the board. It does not report temperature in degrees Fahrenheit or Celsius...that's a task left to the computer.
You can change the output signal by warming or cooling it. Holding it in a warm hand will cause the output to slightly increase from room temperature and holding ice very close will cause it to drop considerably. Protect the thermistor from getting wet to prevent electricity from flowing across the two metal leads and making your output inaccurate.
It's like an on/off momentary push button, but not mechanical. It senses the presence of a body that has the capacity to hold an electric charge...like your body via your finger.
Unlike the others sensors, this one is not analog. It's digital, meaning the output signal is low or 0 volts until a capacitive object, like your finger, becomes close enough to the boxed area and 'flips the switch' causing the output to suddenly jump to high voltage (3.3 volts on the Raspberry Pi). The output returns swiftly back to 0 when you remove your finger.