Lifts & It's indications

Many a times we in the industry, limits ourselves due to overwhelming nature of the proprietary items combined with lack of money to do the renovation and modernization works to upgrade these old yet working systems.
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One such item is the old boiler lifts. One of the many problems with these lifts is that for indications they use 24 volts DC which lights those small bulbs and on number of occasions those bulbs fuse. On top of that these special kinds of long glass incandescent bulbs don't sell much in the market. 
 At the heart of the solution lies a Raspberry Pi computer and the lift cage indications are totally replaced by a sophisticated 4*16 LCD panel which shows temperature, clock , floor number and audio announcement for the floor numbers like that we find in the modern capsule lifts – Otis or Kone lifts.


Schematic:
Normally in an elevator system when the carriage arrives at a landing it throws a crowbar which in turn actuates a number of switches. These switches may be on the +24volt side or on the ground side. In our case it's the ground side. That means the 24Volt indication lamps has the +24volt side already connected and ready , when the switch actuates, it sends the ground connection to the bulb to switch it on. Similarly when the carriage moves past that landing ,the crowbar releases the switch and the ground connections and the bulb goes off.

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Program:
The program is built upon easy python scripts. 
$> sudo apt-get install mpg321
To run the program from the command line ...
$> sudo python lift_light.py &


Alternate Software:
To get rid of mp3 files we can train our Raspi to use a synthesizer program to speak up.
Now complete the installation by adding the following softwares.
$> sudo apt-get install espeak
To know about manual of espeak.
Now run the python program