Production line stop alarm inside
An inside view of the casing with AT90S2313 microcontroller, optocouplers and LEDs wired up.

This module was built for a production line at my previous workplace, its purpose was to serve as a single alarm system controller for an entire production line. It monitored up to eight machines, each with its own alarm timer. If an alarm was triggered; a one second signal was given with the horn. That input would then be muted, and not give any more alarm until the current alarm situation had been cleared for a minimum of seven seconds.

Table of content


All inputs was electrically isolated from the production equipment with optoisolator.

Input pins

  1. PB.0 Equipment #1 alarm signal
  2. PB.1 Equipment #2 alarm signal
  3. PB.2 Equipment #3 alarm signal
  4. PB.3 Equipment #4 alarm signal
  5. PB.4 Equipment #5 alarm signal
  6. PB.5 Equipment #6 alarm signal
  7. PB.6 Equipment #7 alarm signal
  8. PB.7 Equipment #8 alarm signal

Output pins

  1. PD.4 Siren/horn

Schematic drawing

Production line stop alarm circuit
Schematic drawing for production line stop alarm; with AVR AT90S2313. Reset switch and resistors (2.2k) for optocouplers not shown.

Source code


Simple alarm circuit to monitor up to eight inputs, written with BASCOM-AVR.

Master Releases

0 0 0 v1.0 Visual Basic 5 months ago

Image gallery

Parts list

Project: Production line stop alarm by Thomas Jensen is licensed under CC BY-SA 4.0 with attribution required.

Similar resources

  •   Created Mar 16, 2004
  •   Last modified 5 days ago
  • Project status: Given away