Another MIDI controlled lighting rig.

Design Concepts
1

Alo. :slight_smile:

I’ve been running an idea over in my head of a light bulb rig where each bulb can be turned on or off via a midi message. As far as I can tell, I would need a core module (naturally) and a dout module with a ULN2803.

I have a few technical questions though.

  1. Do I interface the ULN2803 to the 74HC595N in the dout module or can I just put the ULN2803 into the socket without needing a 74HC595N?

  2. Do the +/- points of the bulb or the bulb socket just connect to the dout output pins/ground pin?

  3. Is there a way to have the bulbs turn off after a period of time? i.e 500ms or 1s. Would this be software or hardware based?

I’m sorry if the answers to these questions are obvious, just thought i’d get a definitive answer.

Thanks very much :slight_smile:

2

Hi,

  1. Do I interface the ULN2803 to the 74HC595N in the dout module or can I just put the ULN2803 into the socket without needing a 74HC595N?

The ULN2803 is just a driver for the load (in your case lamps). You’ll have to connect them after the 595. Just as mentioned here: http://www.ucapps.de/midio128/relay_example.pdf

  1. Do the +/- points of the bulb or the bulb socket just connect to the dout output pins/ground pin?

No… see the link above. Just substitute “relay” with your lamps. But also take care on the max. load of the ULN outputs. See here: http://www.ucapps.de/midio128/uln2803.pdf

greets

DOC

  1. Is there a way to have the bulbs turn off after a period of time? i.e 500ms or 1s. Would this be software or hardware based?

Both would be possible. It’s easier with software. Doing it by hardware means you’ll have to connect a timer (555 for example) between every 595 and the ULN. 

3

Thanks alot for your reply Doc, straightened things out for me.

I’ll keep you guys posted on what i do with this :slight_smile: