Arduino 433 MHz Wireless Module

433 MHz Wireless Module
The 433 MHz wireless module. Transmitter: top-left. Receiver: bottom-right.

This post provides a quick reference for the 433 MHz wireless module, which is widely used in combination with the Arduino. The VirtualWire library is one possible way of utilizing the module.

Before you get started make sure you have attached antennas to both, transmitter and receiver. The wavelength can be calculated using the following formula.

$$\lambda = \frac{c}{f}$$

For $f=433\text{ MHz}$ this leads to $\lambda = 0.6923\text{ m}$.

Wiring

Transmitter

VCC 3.5 – 12 V Power supply
ATAD Arduino pin 12 Serial data
GND GND Ground (0 V)

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Smart Home Security Camera

This post explains the technical background of the security camera system, shown in the following movie. The post will answer the questions: How to detect a thief, how to take a photo, how to get notifications on your phone, and whether the system would work in reality.

For cutting the movie I made use of iMovie.
iMovie was used for editing.

Links and Quick Facts

The source code is not publicly accessible. For the development I used this configuration.
Buy the system for your home / shed / garage.
Movie background music: LCMC music
Additional information about me.

Technical Details

How to Detect a Thief?

In order to detect a thief I made use of an acceleration sensor that I placed at the apartment’s door. The sensor listens for significant changes in the measured x-acceleration. This technique was so precise, that even the slightest knock triggered the motion detection.

bool motionDetected(float tolerance) {
  readMPU6050SensorData(&mpu6050Data, MPU_addr);
  int16_t accX = mpu6050Data.acceleration.x;
  return (accX > boundaries.max + delta * tolerance || 
    accX < boundaries.min - delta * tolerance);
}

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