Introduction: DIY RF Beacon

Hey guys,

I am back with an all-new instructable. Let's get started.

What is RF Beacon?

An RF beacon is a wireless device that marks a fixed location and allows direction-finding equipment to locate it. It transmits a continuous or periodic radio signal with limited information content — for example, its identification or location — on a specified radio frequency, which is picked up by direction-finding systems on ships, aircraft, and vehicles to determine the location of the device. Occasionally, the beacon function is combined with some other transmission, like telemetry data or meteorological information.

Step 1: Materials Required

  • 1k ohm resistor (R5 R6 R7)
  • 10K ohm resistor (R1 R3 R4 R8)
  • 100K ohm resistor (R2)
  • 10nF capacitor (C2 C3 C4)
  • 10uf capacitor (C1)
  • 2N3904 (Q1 Q2)
  • 555 timer (IC1, IC2)
  • RF module (433 MHz)

Step 2: Circuit Schematic

Step 3: Working

The RF beacon consists of three main units; A low frequency 555 oscillators, audio (high frequency) oscillator, and an RF 433MHz module.

The first unit, a low-frequency oscillator, creates a pulse at a frequency of approximately 1Hz which has an extremely large duty cycle (close to 99.9%). This signal is then inverted thanks to Q1 in the form of NOT gate, this creates a pulse with a duty cycle near 0.01%.

The low duty cycle pulse is connected to the RESET of an audio 555 oscillator. When the output from the low-frequency oscillator stage (after Q1) becomes 0V, the audio oscillator (IC2), is disabled and the result is no audio signal being produced. When the output of the low-frequency oscillator becomes VCC then the audio oscillator (IC2) is enabled and produces an audio able tone. This signal is inverted and then fed into the RF module which emits a tone on the 433MHz spectrum which can easily be picked up by receivers.

Step 4: Generating GERBER for PCB Fabrication

I have designed the schematic using KiCAD. Export GERBER files which have to be sent to the manufacturer in order to manufacture the PCB.

Step 5: PCB Fabrication

I have uploaded Gerber files to LIONCIRCUITS

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Okay, guys. I can share the Gerber files as well if anyone requires it. Feel free.