33 high intensity LEDs are controlled with a AVR ATtiny2313 microcontroller. Four flashing patterns that can be set manually or cycle through. Uses an AVR ATtiny2313 microcontroller.

Table of contents

Details

The emergency strobe light consists of 33 high intensive 5 mm LEDs and control circuit. It has four sequences, and can be set on a single sequence or to cycle through every fifth second. When selecting a sequence manually it is stored in EEPROM and continues on power-up. If an external controlling unit is plugged in; the internal sequences will stop and the external unit is in control. This makes it possible to synchronize multiple units. LEDs are driven by a PWM output, module is powered by 9-24V.

Video

Sequences

  1. Flashing with fade
  2. 3 x strobe, pause
  3. Random pause strobe
  4. Strobe

I/O

Inputs

  1. PD.0 : Automatic mode change
  2. PD.1 : Manual mode change
  3. PD.2 : External controller: available
  4. PD.3 : External controller: pulse constant
  5. PD.4 : External controller: pulse fade

Outputs

  1. PB.0 : Mode 1
  2. PB.1 : Mode 2
  3. PB.3 : LEDs (PWM)
  4. PB.5 : Mode 3
  5. PB.6 : Mode 4
  6. PB.7 : External Mode

D-Sub 9-pin

  1. 12/13.8 V +
  2. 5 V +
  3. GND
  4. Trigger on/off
  5. Trigger fade on/off
  6. Trigger common +
  7. External controller available (N.O)
  8. External controller available (N.O)

Photos

Drilling holes and installing LED holders
Mounting LEDs and resistors
Mounting more LEDs
Mounting and soldering LEDs and resistors
Wiring up LEDs
Working on the enclosure lid
Controller board
Testing controller board
Enclosure done, with lid open
Controller board mounted to the lid
Closeup of LEDs and resistors
Backside of module
Front of strobe module

Source code

Schematic drawing

Schematic drawing of the emergency LED strobe

Parts list

  • 1 × AVR ATtiny2313-20PU, DIL-20, 20 MHz, 18 I/Os
  • 1 × Capacitor, aluminium electrolytic, 10 µF, 25V
  • 2 × Capacitor, aluminium electrolytic, 47 µF, 25V
  • 1 × Capacitor, ceramic, 1 nF, 100V
  • 1 × D-sub soldering cups, 9 pin male
  • 1 × DIL socket, 20-pin, 7.62mm
  • 2 × DIL socket, 6-pin, 7.62mm
  • 1 × Enclosure, plastic (1591), 120x80x59mm
  • 1 × Fuse 5x20 mm, 1 A, fast-acting
  • 1 × Fuse holder, open, PCB, 5x20mm
  • 1 × Fuse holder, open, PCB, Protective cover
  • 2 × Heatsink, 27.3K/W, 19mm, attachable, TO220
  • 4 × LED 3mm, Red, 2.1V, 20mA, 1.0mcd, 38°
  • 1 × LED 3mm, Yellow, 2.0V, 20mA, 2.5mcd, 38°
  • 33 × LED 5mm clear, Blue, 3.4V, 20mA, 7.200mcd, 20°
  • 5 × LED holder 3mm, Black plastic
  • 33 × LED holder 5mm, Black plastic
  • 2 × Metal bracket, 15x50mm
  • 2 × Optocoupler, single, CNY17F-3, DIL-6
  • 32 cm2 PCB, stripboard, 100x160mm, 160cm2
  • 1 × Power jack, panel, 2.1mm, plastic housing
  • 10 × Resistor, carbon film, 0.25W, 330 Ω, 5%
  • 33 × Resistor, carbon film, 0.25W, 560 Ω, 5%
  • 2 × Resistor, carbon film, 0.25W, 4.7 kΩ, 5%
  • 5 × Resistor, carbon film, 0.25W, 10 kΩ, 5%
  • 3 × Resistor, metal film, 0.6W, 1 kΩ, 1%
  • 2 × Spacer, round unthreaded, 3mm, Ø6mm, Delrin
  • 10 × Straight pin header, female, Single row, 2.54mm
  • 10 × Straight pin header, male, Single row, 2.54mm
  • 1 × Switch, toggle, 1-pole, micro, on-off-(on)
  • 1 × Switch, toggle, 1-pole, micro, on-on
  • 2 × Terminal block, pluggable, 3.5 mm, 2-pin screw female
  • 2 × Terminal block, pluggable, 3.5 mm, 2-pin vertical male
  • 1 × Transistor, NPN, 100 mA, 45V, 0.5W, BC547B
  • 1 × Transistor, PNP, 3 A, 100V, 40W, BD242C
  • 1 × Voltage regulator +5V, 2 A, L78S05CV