Bike Direction Indicator – مؤشر اتجاه الدراجة

بسم الله الرحمن الرحيم

Step 1: Introduction

This article focuses on the use of super inexpensive wireless modules that can provide one-way communications capabilities over a reasonable distance.

These modules are also very tiny, allowing you to incorporate a wireless interface into virtually any project.

These modules make use of ASK modulation.

Step 2: Theory – ​ASK (Amplitude Shift Keying)

In Amplitude Shift Modulation the amplitude (i.e. the level) of the carrier wave is changed in response to the incoming data signal. This is sometimes called Binary Amplitude Shift Modulation as there really are only two levels to be concerned with:

  • Digital 1 – This drives the carrier at full strength
  • Digital 0 – This cuts the carrier off completely

Step 3: Antenna Design

One wavelength at 433MHz is 69.24 cm. As this is a pretty long antenna it is more practical to use a half or quarter wave antenna.

Most experimenters use a quarter wave antenna which works out to about 17.3 cm .

It is common to coil the wire on one or both antennas to reduce the size. We can experiment with antenna coils by wrapping the wire around a pencil or pen.

Step 4: Application – Bike Direction Indicator

The application is a use case of the 433 Mhz modules.


  • joystick is used to indicate direction, right, left, stop, and emergency indications
  • The directions data are transmitted asynchronously when events occur
  • The receiver wakes up on Joystick events and make actions by Lighting up the wanted LEDs array
  • The receiver includes an OLED display
  • An MPU6050 a 3-axis Gyroscope with Micro Electro Mechanical System(MEMS) technology may replace the Joystick
  • The gadget is to be installed firmly on a bike

Three boards are designed for this application

  • 433 MHZ tx board
  • 433 MHZ rx board
  • 2 LEDs arrays

Step 5: 433 MHZ TX Board

The 433 MHZ TX module is simple to interface to our ATTINY85 µController.

Step 6: 433 MHZ RX Board

The 433 MHZ RX module is simple to interface to our ATTINY85 µController.

Step 7: LEDs Array Board

A simple array of SMD RED LEDs.

Step 8: PCBs Assembly

Simple boards means simple assembly.

Step 9: Coding

The Code uses the fantastic RadioHead library.

Step 10: Enjoy

A 19 seconds Video is joined to this article.

الحمد لله رب العالمين

Antenna Design (Clone) – (تصميم الهوائي(نسخ

بسم الله الرحمن الرحيم

Step 1: Introduction

Antenna design is not an easy task.

To simplify things, we will CLONE the well known chineese module 2.4 GHZ nRF24L01+.

The nRF24L01+ is a single chip [2.400 – 2.4835GHz] transceiver suitable for ultra low power wireless applications.

Step 2: Documentation

Nordic semiconducteur provides a reference design for the nRF24L01+ chip. It prodives the recommended components too.

Cypress provides an extremely useful article to design a 2.4GHZ antenna.

Our PCB footprint is based on Cypress guidelines.

Step 3: PCB Antenna Footprint

I just followed the Cypress guidelines to draw the footprint. Becareful with dimensions (mils not mm).

Step 4: Schematics

I just reproduced the Nordic Semiconductor reference design in Kicad editor.

Step 5: PCB Design

Kicad is used to route this simple board.

Step 6: PCB Assembly

Becareful with the soldering iron.

Be patient.

Step 7: Enjoy

To test the newly designed Module with its integrated antenna, we used our “Yet Another Remote Controller Board“. Our module fits and replaces the totally cloned chineese equivalent.

الحمد لله رب العالمين