This keypad has 12 buttons, arranged in a telephone-line 3x4 grid. It's made of a thin, flexible membrane material with an adhesive backing (just remove the paper) so you can attach it to nearly anything.Tested in:Arduino NANO, UNO, Mega, Due,  GalileoRaspberry PiLaunch PadProduct Description:Application: Data or programmed inputPad 

The Hall Effect Magnetic Field Sensor 3144 is used to detect magnetic fields. When a magnet is near the sensor, it will output a logic low; otherwise it will output a logic high. Your robot’s microcontroller can read the output via a digital input pin. This sensor can be activated with small household magnets making it useful for a variety of purposes.

• Contact Capacity : AC250V 6A, DC 28V 12AAC 125V 15A, DC 28V 12A;Type : SPDT;Pin Quantities : 5
• Pin Size : 5 x 1mm/0.2" x 0.04"(L*W);Total Size (No Include Pin) : 19 x 15 x 15mm/0.75" x 0.6" x 0.6"(L*

When the future is dazzlingly-bright, this ultra-high-range luminosity sensor will help you measure it. The TSL2591 luminosity sensor is an advanced digital light sensor, ideal for use in a wide range of light situations. Compared to low cost CdS cells, this sensor is more precise, allowing for exact lux calculations and can be configured for different gain/timing ranges to detect light ranges from 188 uLux up to 88,000 Lux on the fly.

The best part of this sensor is that it contains both infrared and full spectrum diodes! That means you can separately measure infrared, full-spectrum or human-visible light. Most sensors can only detect one or the other, which does not accurately represent what human eyes see (since we cannot perceive the IR light that is detected by most photo diodes) This sensor is much like the TSL2561 but with a wider range (and the interface code is different). This sensor has a massive 600,000,000:1 dynamic range! Unlike the TSL2561 you cannot change the I2C address, so keep that in mind.

The built in ADC means you can use this with any microcontroller, even if it doesn't have analog inputs. The current draw is extremely low, so its great for low power data-logging systems. about 0.4mA when actively sensing, and less than 5 uA when in power-down mode.

This is a simple two wire cable. Great for jumping from board to board. 2-pin JST connector on one end, bare cable on the opposite end.

These are very thin variable potentiometers. By pressing down on various parts of the strip, the resistance linearly changes from 100Ohms to 10,000Ohms allowing the user to very accurately calculate the relative position on the strip. Can be used as an accurate positional indicator for CNC head positioning, variable user input (volume level input for example), straight user input (multiple button areas translate to given resistance levels), and many other applications.

Unit comes with adhesive backing. Connector is 0.1" spaced and bread board friendly.

10K Logarithmic Slide Potentiometer Log Slide Pot Potentiometer Module Dual G5M3

300 Degree Rotation Sensor Rotation Angle Potentiometer for UNO Rev3 Micro Controller

IR based reflective object/proximity sensor.

12v 1 Channel Infrared Switch Relay Driving Module Board Remote Controller.

LM2596s DC-DC step-down power supply module 3A adjustable step-down module LM2596 voltage regulator 24V 12V 5V 3V

This sensor is ideally suited to measuring liquid across it. The sensor outputs a pulse that is relative to the speed at which the internal pinwheel is being turned. This can be calculated by dividing the output pulse by 7.5, which produces the flow rate in litres per minute. This makes for a simple and effective method for monitoring watering/hydroponic systems as well as other fluid based control systems.

This DC/DC step-down voltage converter is based on MP2303, it converts input voltage between 4.5V and 28V into a smaller voltage between 0.8V and 8V, capable of driving a 3A load with excellent line and load regulation.

Note: Input must be >1.5V higher than output! The chip will get to high temperature protection mode when it work at a high-power conversion, without any cooling, it is able to output 3A current at 5V. But at higher output voltage, the current output capacity is lower than 3A, approx 2A.

Instructions
1. photoresistors module is most sensitive to ambient light, generally used to detect the brightness of the ambient light.
2. when the ambient light is darker than the threshold value is set, the relay is energized, the common terminal and the normally start is turned on, when external ambient light is brighter than the set threshold value, the relay is switched off, the common terminal and the normally closed end connected.
3. the public side, normally open, normally closed three ports, the equivalent of a dual-control switch, relay coil power, public end and often the beginning of conduction, radio, public end normally closed terminal conduction.

This Bluetooth module can easily achieve serial wireless data transmission. Its operating frequency is among the most popular 2.4GHz ISM frequency band (i.e. Industrial, scientific and medical). 
It adopts Bluetooth 2.1+EDR standard. In Bluetooth 2.1, signal transmit time of different devices stands at a 0.5 seconds interval, so that the workload of Bluetooth chip can be reduced substantially and more sleeping time can be saved for Bluetooth. 
This module is set with serial interface, which is easy-to-use and simplifying overall design/development cycle.