A control module for a green, yellow and red stack light, and signalling horn. Uses an AVR ATtiny2313 microcontroller.

Table of contents

Details

This is the rack box alarm handling unit. It controls the stack light, strobes and horn. Six different signals can be displayed, depending on the alarm situation. If mute is active; no signals is given. The power transistors for the stack light used to be located inside the module, hence the heat-sink. They have been moved to a separate power transistor unit.

Video

Signals

Situation Green Yellow Red Strobe Horn
Flashing 0.1
Rack temp Steady Flashing Yellow 1 s
SIOS alarm Flashing Yellow 1 s
Serial offline Flashing Steady Yellow 1 s ⭐
Module offline Steady Flashing Red 1 s ⭐
Supply error Flashing Red 1 s ⭐

⭐ 0.1 s when muted

I/O

Inputs

  1. Signal 1
  2. Signal 2
  3. Signal 3
  4. Signal 4
  5. Signal 5
  6. Signal 6
  7. Mute

Outputs

  1. Stack light green
  2. Stack light yellow
  3. Stack light red
  4. Strobe yellow
  5. Strobe red
  6. Horn
  7. Life-signal (to Module stability monitoring unit 2)
  8. Life-light

D-Sub 25-pin

  1. +5V
  2. 0V
  3. Strobe yellow
  4. Strobe red
  5. Horn
  6. Life-signal
  7. Signal 1
  8. Signal 2
  9. Signal 3
  10. Signal 4
  11. Signal 5
  12. Signal 6
  13. Mute signal
  14. Stack light green
  15. Stack light yellow
  16. Stack light red

Source code

Photos

Cutouts in plastic enclosure
Inside module
Testing the module
Module complete
Module installed in the Rack box project
External power transistors for the stack lights
Stack lights, and a bottle of Ballantine’s
Inside the module
Inside the module

Schematic drawing

Schematics for the stack lights controller

Parts used

  • 1 × AVR ATtiny2313-20PU, DIL-20, 20 MHz, 18 I/Os
  • 1 × Capacitor, aluminium electrolytic, 10 µF, 25V
  • 2 × Capacitor, ceramic, 22 pF, 100V
  • 1 × Capacitor, ceramic, 1 nF, 100V
  • 1 × D-sub soldering cups, 25 pin male
  • 1 × DIL socket, 20-pin, 7.62mm
  • 1 × Enclosure, plastic (1591 FL), 120x65x40mm, flange
  • 1 × Fuse 5x20 mm, 400 mA, fast-acting
  • 1 × Fuse holder, open, PCB, 5x20mm
  • 1 × Fuse holder, open, PCB, Protective cover
  • 1 × Heatsink, 6K/W @ 10W, 37.5mm 49g
  • 1 × LED 5mm coloured clear, Green, 2.1V, 20mA, 30mcd, 10°
  • 1 × LED 5mm, Green, 2.0V, 10mA
  • 1 × LED 5mm, Orange, 2.0V, 20mA
  • 1 × LED 5mm, Red, 2.0V, 20mA
  • 1 × LED holder 5mm, RTC51, black plastic
  • 96 cm2 PCB, stripboard, 100x160mm, 160cm2
  • 1 × Quartz crystal oscillator, 4 MHz
  • 11 × Resistor, carbon film, 0.25W, 330 Ω, 5%
  • 8 × Resistor, carbon film, 0.25W, 4.7 kΩ, 5%
  • 7 × Resistor, carbon film, 0.25W, 10 kΩ, 5%
  • 7 × Transistor, NPN, 100 mA, 45V, 0.5W, BC547B