:: Wireless Stage Light Controller ::

Thread Starter


Joined Oct 27, 2006
final year masters project in UK... ive already done alot of the work for it, i have a visual basic application i built to communicate hex numbers to two recievers (wired at the moment) and the reciever PIC's processes what ive sent, and decides how bright each output should be ... (240AC powered bulbs)

At the moment i want to use 12v BULBS to test it all out on, at the moment i have pics controlling outputs on or off via visual basic...

im doing the power side of the circuit and playing with TRIACS... im getttin out my depth in terms of power electronics, i hope i can get help here...

any1 had use of ZERO CROSS DETECTORS... i.e. circuitry to let me know when the AC signal passes zero, i want this to interrupt my pic and then start a timer (dependant on brightness value) and turn on the triac after this delay

and also bridge rectifiers... some ckts i see 4 diodes and some are 2... i want the ac signal to be sent to a 5v reg...after a transformer giving me ~10v ac...to 5v dc...

any help?


Joined May 16, 2005
The full wave rectifier is made from either four diodes or two diodes. The four diode version does not require a center-tapped transformer, the two diode version does.

There are many versions of the zero crossing detector available on the internet. I have a vague memory of one on a chip, but can't find my notes on it now.

Thread Starter


Joined Oct 27, 2006
The ckt for the transformer i had in mind was this...

the TRAINAGLE SYMBOL grounds (signal grounds...) where do i connect this up to?

i have three wires coming in... L/N/E from the plug... i have no idea where and how to ground my signal side of the circuit..


Also im using a variac at the moment, at 12v AC...so basically im supplying the voltage at the OUTPUT side of the transformer, is that ok or will i have problems with my test setup when i want to use a transformer and a 240v ac supply?



Joined Dec 2, 2005

The three wires are most likely Line, Neutral, and Earth.

Line is black and is connected to the 'hot' side of the circuit breaker. Neutral is 'white' and is bonded to the Earth (Green) at the load center. Usually, it is a good idea to NOT connect the power supply ground (triangle symbol) to the green wire (building ground). It is usually a good idea to keep the DC supply isolated from the 'mains'. This is how your schematic shows things.

One thing when using a variac to keep in mind is that the 'mains' voltage (unless you use a isolation transformer) is NOT isolated from the circuit you are working with....BE CAREFULL!