Screw Terminals with 3.5mm pitch 2 pins. Comes in 2 or 3 positions and havethe really cool feature of slide-locking together to form any size you need (4,5, up to 20 without problems). Rated up to 125V @ 6A. Terminal can accept 30 to20AWG wire. 3.5mm/138mil pin pitch will not fit\'standard 0.1" perf boards butthis is the most common pitch...
This adapter allows you to connect a barrel jack connector to bare wires. One end has screw terminals and the other has a 5.5x2.1mm, center-positive male barrel jack. If you need to connect bare wires to a barrel jack on an Arduino or a development board, this might be the simple solution.
Miniature Single Pull Single Throw switches. These are high quality Omron type B3F momentary on switches. This switch has a very large 5mm tall button. Perfect as an embedded switch behind an enclosure wall. Rated up to 50mA.
Single row of 30-holes, female header with swiss round machined pins. These units have very high quality round pins to accept and retain machine pin headers much better. Can be cut to size with a pair of wire-cutters. Standard .1" spacing. We use them extensively in the Olimex development boards. They mate very well with break away headers.
LEDs - those blinky things. A must have for power indication, pin status, opto-electronic sensors, and fun blinky displays.This is a very basic 5mm LED with a red lens. It has a typical forward voltage of 2.0V and a rated forward current of 20mA.
If you are sourcing a ultrasonic ranging module , the HC-SR04 is good choose . Its stable performance and high ranging accuracy make it a popular module in electronic market .Compared to the Shap IR ranging module , HC-SR04 is more inexpensive than it . But it has the same ranging accuracy and longer ranging distance.