# RF seemingly complex project

#### ace hardware

Joined Apr 20, 2007
6
Please be gentle with me. I am new to all of this, but I have an idea I need help with.

I am trying to develop a wireless circuit that will allow me to randomly light up 12 different lights at one at a time with a cut off switch attached to each one. Hopefully this is enough to get us started. Please someone point me in the right direction to get this idea off the ground

#### thingmaker3

Joined May 16, 2005
5,084

Do you want to randomly send a wireless signal to one of 12 recievers, or do you want to send a random control number to a reciever with 12 outputs?

Do you require a psuedo-random generator? One light only, or a group of randomly selected lights?

Is the cutoff switch on each light wireless as well, or manual?

Is the cutoff switch an over-ride or a reset?

Are the lights low-power LEDs or 480VAC mercury-vapor floodlamps?

#### ace hardware

Joined Apr 20, 2007
6
I will endeavor to answer the questions to the best of my ability.

The lights will be low power LED.

I would like to randomly send signal to one of 12 receivers. Then when that one is turned of by the switch that is wired to them, another of the lights will automatically be picked at random to come on. When that light is switched of another is automatically picked at random to come on. These light can come on more than once during the scenario or not.

This should allow only one light at a time to burn.

The switch can be an overide or a reset either one. Hopefully this is enough info. If not, I wll try again.

Thanks
ace hardware

#### thingmaker3

Joined May 16, 2005
5,084
So... when my LED lights I push a button. My light goes dark and one of the other eleven light at random. Sounds like part of a fun game, simply insert human activity between light and button-pushing.

Anyway... You'll need twelve circuit boards, each of which has a power supply, the LED and driver, a transmitter, a reciever, and a pseudo-random generator.

Rather than use 12 different frequencies, I suggest transmitting a number code. The recieveing units can decipher the number into "me" versus "not me."

#### recca02

Joined Apr 2, 2007
1,214
can we not use a random binary no generator (i dont know how to do that)
and a demux?

#### kubeek

Joined Sep 20, 2005
5,656
I would use some processor as the central unit, which will make the random decisions and ocassionaly send a code to the lights through RF transciever.

Each light would have its reciever and decoder.
Now you can choose the coding technic, either use one code to switch on and another to switch off; or you can use first time on, second time off, third on (...)
I would suggest using the first method, because it is more flexible and reliable.

The program in the control unit will most likely do:
get new random numbers for the delay to wait and number of the light
wait for the random time
switch transmitter on
send the ON code to the light - keep repeating the code few (hundred) times
switch transmitter off
go to beginning

#### kubeek

Joined Sep 20, 2005
5,656
Or do you need the lights to be switched off manualy, and send it to the central unit? That probably isn´t worth doing by RF, it will cost a fortune just to develop it.

#### ace hardware

Joined Apr 20, 2007
6
I do need the light to be switched off manually. How much of a fortune would we be talking to develop it?

#### thingmaker3

Joined May 16, 2005
5,084
Wild guess: $250 USD for components to make twelve units. Breakdown:$6 or $7 USD each for monolithic RF tranciever chips$7 or $8 USD each for microcontroller chips$5 or \$6 USD each for LEDs, regulators, and miscellaneous stuff
Rounded up to nearest convenient value

Does not include etching equipment, misc. tools, programmer for microcontroller, batteries, or beer. Assumes all work done by unpaid person.

#### kubeek

Joined Sep 20, 2005
5,656
It will also take a lot of time to develop it.

Does it really need to be wireless? Are the power wires lead to a common point? If yes, then the lights could comunicate through the "power bus", or you could add another wire for serial comunication..

#### thingmaker3

Joined May 16, 2005
5,084
With hardwiring, price would drop by a factor of ten or more. Only one microprocessor would be needed, and no RF components.

#### ace hardware

Joined Apr 20, 2007
6
It definitely needs to be wireless.

So, to make sure we are all on the same page, we have our micro-processor (MP) that controls everything.

A signal is sent to one light turning it on; when the switch for that light is "tripped" the light goes off and a signal is sent back to the MP which then sends a signal to another light at random. This continues for a specified period of time (also controlled by MP but not randomly).

Question: How large would a box containing 1 of these lights with all of its components have to be? How compact can we make it?

I appreciate the help thus far--it seems I can see the (12) lights at the end of the tunnel.

Ace Hardware

#### windy

Joined Apr 19, 2007
26
I have a question for you.

Is this a project for inside use?

will hiding these boxes be part of the project?

Will they be within hearing range?

How much distance will these units have to transmit

#### thingmaker3

Joined May 16, 2005
5,084
Okay. Thirteen boxes. One has power supply, uProc and Xcvr. Other twelve have power supply, Xcvr, light and button. With no uProc in the twelve boxes, the One box must use twelve different frequencies. You might consider something similar to Texas Instruments CC1150 chip.

Assuming power supply for the twelve light units is a battery, size can be a little larger than the battery.

#### ace hardware

Joined Apr 20, 2007
6
Transmitting no more than 65 feet.

Inside or Outside use--It is important that this be easily transportable once assembled.

Hearing range? All components will be within 65 feet of each other.

Hiding the boxes not necessary.

THINGMAKER3--Thanks for hanging with me. You're moving me down a pretty cool road here. Keep checking this thread if you dont mind--I'll be back for more no doubt.

ALL OTHERS--All input or suggested possibilities are welcome

ace hardware

#### kubeek

Joined Sep 20, 2005
5,656
So another bunch of queries:

Do you know what the power source will be for the lights and for the controller? If yes what are they?
Do you prefer uProc in each light or using 12 frequencies?
What about using IR communication, would that be possible?

What is your budget for the whole setup?

#### ace hardware

Joined Apr 20, 2007
6
Lights will need to be battery powered--a small, long life battery of some kind.

The control box Can be just regular AC/DC powered thru a cord and surge protector.

uProc vs. Freq--I'm open to suggestion. Size and price do play a part--both need to be as small as possible
Reliability is also a big deal.

IR will work IF it will work. I need something reliable and long lasting that will do all of the things previously discussed. In my (very limited) mind, it seems that RF would be more reliable.

Budget is open(12 light pods and 1 controller) Lets be as economical as possible. Of course I'm not looking to waste or have overkill as far as the components that are used--but quality and durability are necessary.

The interest is appreciated.

ace