Gabriel:
I tend to agree with Steve.

A real good solution I have found for a project such as you are talking about is to use the cool part called the TDA8444. This little beauty gives you eight DAC channels in one 16-pin package. And even better it takes just two microcontroller pins plus a small amount of I2C interface software to talk to it.

The DACs are 6-bit resolution so you get 64 levels of control. That should be perfect for lighting control.

Here is a link to Philips information page for this device.

http://www.semiconductors.philips.com/pip/TDA84...4P_N4.html

Good Luck
Michael Karas


PS...It seems like the solution you were talking about using a single R2R ladder and a 4051 mux would only allow you to support one lighting channel at a time unless you equipped each output with a sample/hold chip. The TDA8444 is a much better choice. Each output will hold its programmed output voltage until a new value is selected.
MJK