ESBS - Strasbourg

Lighting device

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Lighting device

1. Introduction

To make the characterization of our biological system we developped a lighting device which can be controlled from a computer. The goal of this device is to create red and infrared pulses which period and duration are fixed by the user in a computer interface.

The lighting part of the device is composed of two parts:
• A LEDs band which is composed of four red LEDs put alternately with four infrared LEDs and used to enlighten a tube
• A box subdivided into a 3-by-3 matrix of compartments, each one containing a red and an infrared LED and used to enlighten independently nine biological materials

These two parts are represented on the following scheme:

2. Printed circuit board

We designed the printed circuit board with Kicad, a free PCB design tool. You can download Kicad at this address:

Here you can download the PCB file of the circuit:

The following picture explains the different components used:

And here is the list of the corresponding components used:

• A1, A2, A3, B1, B2 , B3, C1, C2 and C3: LEDs connectors
• B1: LEDs band connector
• Q1: quartz 4 MHz
• PIC: Microchip PIC 18F452
• MAX: MAX232
• DB9: DB9 connector
• PB: reset button
• P1: power connector (9 V)
• P2: 78L05L voltage regulator (5 V)
• R1: LEDs resistors (100 Ω)
• RC1: resistor (10 kΩ) and capacitor (100 nF) for the reset
• C1: quartz capacitor (33 pF)
• C2: power decoupling capacitor (33 nF)
• C3,C4,C5,C6: MAX232 capacitors (10 µF)
• C7: 78L05L capacitor (330 nF)

3. Microcontroller software

The microcontroller used is a Microchip pic 18F452 which is easily programmable in C language with MPLAB combined to a C18 compiler. The link between the computer and the microcontroller is carried through the serial port.

Here you can download the hex file of the program:

And here are the source files of the software:

4. Computer software

We developped the computer software with Microsoft Visual C++. You can download Express version at this address:

The following picture illustrates the software interface:

Here you can download the software:

And here are the source files: