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CMT2156 Self-powered Wireless Switch Module

SKU: TEL0146

DFRobot’s CMT2156 Self-powered Wireless Switch Module needs no battery. It converts pressing kinetic energy to electricity via electromagnetic induction, transmitting 433MHz wireless signals. Maintenance-free, it suits wireless doorbells/pagers. A receiver (e.g., official Gravity 433MHz receiver supporting EV1527 decoding) is required. Notes: Don’t press the power button when connected to DC; at least one dip switch must be up to avoid chip damage.

Angled shot of self-powered wireless switch with coiled wire and internal circuitry.-DFRobot product sku:TEL0146 image.

Downloadable Resources

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  • Tech Specs
  • Blog
  • Certifications
    • 1. Getting Started

    The crucial safety measures for module usage, focusing on proper power supply connection, dip switch settings, and pressing frequency to prevent chip damage.
    2. Receiver Configuration Guide

    This guide provides detailed instructions on configuring the DFRobot Gravity digital wireless switch receiver, including mode switching and pairing techniques, helping users optimize their receiver setup for varied applications.
    3. Usage Example for Arduino - Wireless Signal Reception and Pairing
    Reference

    This article delves into two switch modes for signal transmission: 'press, store energy, bounce, transmit' with energy storage and 'press, transmit, bounce, transmit', highlighting their workflows and impact on signal emission.

    Specification

    Parameter Value
    Working Frequency 433Mhz
    Transmission Rate 10kbps
    Encoding Format EV1527
    Output Power 13dBm
    Modulation Method OOK
    Power Generation Energy 600uJ
    Module Size 47x25x11mm(LWH)/1.85x0.98x0.43”
    Press Down Force Typical 1800g
    Action Method Automatically rebound after pressing down
    Action Distance 2.6mm (end point)
    Press Frequency no more than 3 times per second, long-term rapid press will cause energy accumulation and cannot be consumed in time, and eventually burn the chip
    Stable Transmission Distance Indoor 40M
        - Distance Test Condition: Straighten the wire antenna of the transmitting module, and for the receiving module, use Gravity: Digital wireless switch receiver(433MHz)

    Pinout

    Name Function
    1. DC input terminal The DC power input terminal, 3.3V-5V, can transmit signals directly after being connected to the DC power supply. Used to pair with the receiver;
    2. DIP switch Key value selection, dial up to select, from right to left is D0~D3, One must be dialed up when using
    3. Power Push Button Generate energy when pressed
  • RoHS RoHS
  • REACH REACH

    • FAQ

    • Which resistor is the bleed resistor in the 433MHz Self-powered Wireless Switch?

      The R2 and R4 are the bleed resistors in our schematic.

    • Which jumper pads need to be soldered to enable message sending on button press/release for the Self-powered Wireless Switch (433MHz)?

      Please solder these two pads marked in the picture:

    • Long press reduces TX range? Check energy storage leakage or signal damping.
      If you press the button and release it quickly when you use it, you don’t need to consider this issue. To ensure that the stored energy will not accumulate and cause the chip to burn out, a bleeder resistor is added to the system. In the "press, store energy, bounce, transmit" mode, the stored energy will begin to bleed slowly after the button is pressed. If it takes a long time, this part of the stored energy will be slowly exhausted by the bleeder resistor. If you have to press it down for a period of time before transmitting the signal during use, you can remove the bleeder resistor at the energy storage terminal. However, it must be noted that in this state, if a DC power supply is used to power the module (DC power supply is required for pairing learning), the energy storage capacitor will be in a state of full energy after the DC power supply is disconnected. Then a bleeder resistor must be connected to discharge the energy storage capacitor to below 1.5V. If the power generation switch is not discharged at this time, the chip will be burned directly when you press down the button. And when the bleeder resistor is removed, it is strictly forbidden to press the power button quickly in a continuous manner. The discharge resistors are R4 and R2. R4 is used to dissipate the energy generated when the button is pressed, while R2 is used to dissipate the energy generated when the button is released.
    • What should be noticed when using this self-powered wireless switch with receivers from other manufacturers?
      You need to pay attention to whether the receiver supports EV1527 decoding and 10Kbps rate. EV1527 encoding and 10kbps is a very common standard.

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