Rack box project

From CaveLab
This page is kept for historical interest. It may document projects or methods that are obsolete and/or no longer relevant. The information here is not kept up-to-date.

This project was terminated when I moved out of my first apartment.
Rack box 13. April 09

The rack box is the center for many of the modules I build, inside is the controlling units for lights, heat, stack light, fan, sound alarms and serial communication. The rack box is a 19" standard rack box, even though very few of the modules inside are standard. The construction is in steel and everything is grounded, this gives good protection from radio frequent noise. 220V is connected to the rack box through a net filter, this is distributed to four power supplies; 5, 12, 13.8 and 24 volt.

All fuses, power supplies and modules are monitored and the rack box will sound an alarm if anything should fail. Many of the modules inside are surveillance and monitoring units, and not actively in use. This is true for e.g. Main monitoring unit, Module stability monitoring unit 2 and Signal and lights controlling unit. Four DB-9 connectors supplies the rack box with signals from the outside. In addition to that, multiple serial cables run to modules like Online monitoring unit 2 and Online serial interface device.

The rack box has an emergency shutdown function that cuts the main power to the system, this has to be triggered manually from either the Rack status panel or inside the box. In the future modules like a smoke detector could trigger the emergency shutdown automatically. The Emergency shutdown unit controls the emergency function, it's 12V power supply is not influenced by the emergency shutdown. An external power supply is used for detecting total power loss, this supply is also monitored by Main monitoring unit.

Today the rack box is getting crowded, with now over 15 modules. I'm installing more and more modules on-site with battery eliminators and internal voltage regulators. This is true for e.g. Light sensor, Mood light controller and Mood light.


This video is also available on YouTube.
This video is also available on YouTube.


Rack status panel

Rack status panel has LEDs for pretty much every situation that can occur in the rack box. Lights, alarms, fan, mute etc. can also be controlled from the panel. Emergency shutdown can both be triggered and reset from Rack status panel. It's made of a desk box with a aluminum front plate, this is stiff and provides and does not bend when buttons are pushed.

The panel is connected to the rack box using three contacts, one 9-, 25- and 37 pins D-sub cable. If one of the cables are disconnected or the fuse burns out the alarm will sound, the panel is monitored by Multi-purpose module 1. Digital emergency interface module is installed inside the Rack status panel and connected to the computer using a DB9 serial cable. All voltages (5, 13.8 and 24) is available via lab plugs. The alarm (Alarm unit) can be activated/deactivated using the key. When the alarm, or away mode is active all LEDs are turned off and none of the buttons work.


The rack box alone without any alarm, lights etc. has a power consumption of 13 watts. When the stack lights or the interior light is on the power consumption rises to about 20 watts. The rack box is protected with a net filter and a UPS, the UPS prevents the system from going offline if a power loss occurs.


An external 12V power supply is used for detecting total power loss, meaning that the system is running on battery backup (UPS).