A membrane matrix keypad is a type of input device that consists of a flat, flexible membrane with a grid of conductive traces printed on it. When a user presses one of the keys on the keypad, the membrane is depressed, causing the two conductive traces beneath the key to make contact and close a circuit. The keypad sends a signal to a microcontroller or other control system, indicating which key has been pressed.

A 20-key membrane matrix keypad typically has a grid of 4 columns and 5 rows, resulting in a total of 20 keys. The keypad can be used to input numerical or alphabetical data, or it can be used to trigger certain actions or commands. Membrane matrix keypads are commonly used in a variety of applications, including in consumer electronics, appliances, and industrial control systems. They are inexpensive, easy to use, and durable, making them a popular choice for many applications.

Use this awesome 20 key, 4x5, membrane keypad for all your Arduino input needs! It is easy to use, flexible, light-weight and looks professional.

• Contact resistance of 500
• Insulation resistance 100M
• Key Operating Force 150-200N
• Rebound time 1 (ms)
• Life of 100 million (times)
• Operating Temperature 60
• 1.The electronic characteristics:
• Circuit Rating: 35V (DC), 100mA, 1W
• Contact resistance: 10Ω ~ 500Ω
• (Varies according to the lead lengths and different from those of the material used)
• Insulation resistance: 100MΩ 100V
• Dielectric Strength: 250VRms (50 ~ 60Hz 1min)
• Electric shock jitter: <5ms
• Life span: tactile type: ≥ one million times
• 2.The mechanical properties
• Operating pressure: Touch feeling: 170 ~ 397g (6 ~ 14oz)
• Switch travel: touch-type: 0.6 ~ 1.5mm
• 3.The environment parameters
• Operating temperature: -40 to +80
• Storage temperature: -40 to +80
• Temperature: from 40,90% to 95%, 240 hours
• Vibration: 20G, max. (10 ~~ 200Hz, the Mil-SLD-202 M204.Condition B)