Skip to Content
  1. All products
  2. 🧠 Controllers & Systems
  3. 3x4 Matrix Telephone-Style Keypad – 12-Key Rugged Tactile Input for Arduino & Access Control
  4. 🧠 Controllers & Systems
मूल्य सूची: Retail Price (B2C) मूल्य सूची
मूल्य सूची: Retail Price (B2C) मूल्य सूची
3x4 Matrix Telephone-Style Keypad – 12-Key Rugged Tactile Input for Arduino & Access Control

3x4 Matrix Telephone-Style Keypad – 12-Key Rugged Tactile Input for Arduino & Access Control

(0 review)
FeatureDetails
Configuration3x4 Matrix (12 Keys)
LayoutTelephone Style (1-9, *, 0, #)
Button TypePlastic Push-Buttons (Tactile)
Connector7-Pin Male Header (2.54mm Pitch)
Contact Resistance< 100 Ω
DurabilityHigh-Impact ABS Plastic
Price
₹ 186.44 ₹ 186.44
(Tax included)

Product Description The ACS712 30A Current Sensor Module provides an economical and precise solution for AC or DC current sensing in industrial, commercial, and communications systems. Based on the Hall-effect principle, the module features a copper conduction path located near the surface of the die. When current flows through this path, it generates a magnetic field which the Hall IC converts into a proportional analog voltage. The 30A variant is specifically designed for high-power applications such as motor control, load detection, and overcurrent protection. Its primary advantage is the 2.1 kV RMS electrical isolation between the high-current conduction path and the low-voltage sensor electronics, ensuring safety for microcontrollers like Arduino and ESP32.

Key Features

  • Bi-Directional Sensing: Capable of measuring both positive and negative current flow up to 30 Amperes.

  • Galvanic Isolation: The conduction path is electrically isolated from the sensor leads, protecting your control circuitry from high-voltage spikes.

  • Low Internal Resistance: The 1.2 mΩ internal conductor ensures minimal power loss and prevents the sensor from heating up during high-load operation.

  • Analog Output: Provides a linear voltage output centered at VCC/2 (2.5V for a 5V supply) at zero current, simplifying signal processing.

  • High Bandwidth: Supports up to 80 kHz sensing, making it suitable for monitoring fast-switching power supplies and PWM motor drivers.

Technical Details

  • Scanning Logic: Operates on a row-column matrix; pressing a key shorts one row pin to one column pin, which is detected by the MCU.

  • Contact Material: High-conductivity silver ink traces ensure reliable signal transmission and low contact resistance.

  • Debouncing Requirements: While the membrane has a fast response, software debouncing is recommended for clean signal detection.

  • Pin Configuration: 7 Pins total (4 Rows: R1, R2, R3, R4 and 3 Columns: C1, C2, C3).

  • Actuation Force: Requires a gentle 150g to 400g of pressure for a tactile, reliable keypress.

  • Voltage Flexibility: Passive device that works with any logic level (1.8V, 3.3V, 5V, or 12V) provided by the host controller.

  • Storage Temperature: Stable storage capabilities from -40°C to +80°C.

  • Humidity Resistance: Designed to operate in environments with up to 90% non-condensing humidity.

  • Lead Length: Features a flexible ribbon cable extension (approx. 80mm) for versatile internal wiring.

  • Key Pitch: Standard spacing between keys for comfortable finger operation.

  • Matrix Type: Passive switch matrix; requires no external power to the keypad itself, only to the logic pins.

  • UV Resistance: High-quality graphic overlay is resistant to fading under indoor lighting conditions.

  • Standard Interface: Directly compatible with the standard "Keypad.h" library in the Arduino IDE.

  • Impact Resistance: Flexible PET layers absorb minor shocks without damaging the internal conductive traces.

  • Industrial Utility: Widely used in vending machines, specialized calculators, and access control prototypes.

Prototyping and Engineering Tips from Robogears

  • 9V Battery Use: This is a passive matrix switch and does not consume power. You can use it in 9V circuits (like a standalone lock), but ensure your microcontroller pins are protected. Never connect 9V directly to the ribbon pins as they lead to your MCU's logic pins.

  • 18650 Cell: Perfect for low-power battery devices. Because the keypad only conducts when a button is pressed, it is ideal for "wake-on-interrupt" circuits that save 18650 battery life.

  • IC & Capacitor Tip: For high-security projects, use an IC 74C922 Keypad Encoder to convert the 7-pin matrix into a 4-bit BCD output, saving MCU pins. To reduce noise in long cables, add a 0.1uF ceramic capacitor near the MCU's input pins.

  • Related Products: We recommend pairing this with our 16x2 I2C LCD Displays, Solenoid Door Locks, and Arduino Uno R3 for building digital security systems.

Package Includes

  • 1 x 4x3 Matrix Membrane Keypad (12-Key).

Disclaimer Image is for ilastration purpose only 2-3 lines. Do not fold or sharply bend the flexible ribbon cable near the connector or the keypad entry point, as this can break the internal silver traces. Ensure the mounting surface is clean and dry before applying the adhesive.