Build your own Wireless Network detector using PIC12F629

What This Is

This project is for a small electronic unit that allows the user to sense the presence and relative signal strength of wireless hotspots. It can be worn as a pendant or carried in a pocket. It is “always on” and communicates the presence and signal strength of an in-range hotspot by way of sequences of pulses – like a heartbeat you can feel. The stronger and faster the “heartbeat”, the stronger the wireless signal detected.

sensor guts illustrated

It does not actually authenticate or otherwise interact with a hotspot in any way. It is a 100% passive device, meaning it transmits nothing — it can detect hotspots, but cannot be detected itself.

How It Was Made

This project consists of a microcontroller, some custom interface electronics, a small vibe motor, and an off-the-shelf Wi-Fi detector – the one I used is by D-Link and is keychain-sized.

Here is the sensor I used, and some pictures of the construction. Details of the design will follow.

How It Works

The microcontroller periodically “presses” the button on the detector to initiate a reading. Then the microcontroller “reads” the output from the indicator LEDs on the detector, and uses this as the basis for pulsing out a signal on the vibe motor, which the wearer can feel.

In this way, the unit keeps you updated on the presence and signal strength of a wireless hotspot in your vicinity. No pulses means no signal. Short pulses means a weak signal. Faster, more frequent pulses means a stronger signal. This feedback is very much like a heartbeat, and is extremely intuitive to interpret.

How To Make Your Own

First of all, I use a microcontroller in this project. If you aren’t familiar with terms like 12F629 or .HEX files and how to blast them into a PIC, you will have trouble with this project.

The D-Link sensor I used works like this — press the button and the LEDs light up in a “scanning” pattern while it looks for a signal. It can be in this scanning pattern for up to a few seconds. Afterwards, it lights up either one, two, three, or four of the green LEDs to indicate relative signal strength. If there is no signal detected, a single red LED is lit. The LED(s) remain lit for a few seconds, then the sensor shuts off.

If your chosen sensor works differently, you will need to adjust the electronic interface and the program in the microcontroller accordingly.


READ  "Mini-Beacon" miniature programmable LED Flasher that is based around a PIC12F629 microcontroller

For more detail: Build your own Wireless Network detector using PIC12F629

Current Project / Post can also be found using:

  • pic ethernet
  • Build your own Wireless Network detector using PIC12F629

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