Add Some Public Interaction to Your Display!

What is an "Interactive Circuit"?  It's what I describe as any part of the display which your guests can control.  In our display, we have several buttons along our  Christmas fence which are lit and activated during the 45 seconds we have between musical sequences. 

This is how is works.  I'll explain how it's built at the bottom of this page.

During our intermissions, the LED above this button will light, (Separate LOR channel), indicating that the button is now active.

Pressing it will short out the 2 blue wires in this jack located on the back of the fence post.

The other end of the wire terminates in a standard 12 port telephone 'Bix Block'.

This block is hardwired to my 'interactive relay' box.

Whatever is plugged into the corresponding outlets, will now light.

In a nutshell, that's how it works.  If you'd like to build this yourself, here are some more elaborate instructions with a basic schematic. 

How to Build it

Having spent several years in the telecommunications field, I am fortunate to have access to a telephone surplus store where I pick up  A LOT of my parts.  Most of these parts (including the Bix block, which I feel is integral to this project) can be purchased at Home Depot and many other telecommunication suppliers.  Spend the time to track one down, and you'll be much happier with your results.

Before we begin, I want to mention that this project could be made much easier by running 110VAC right to the button, and then to the lights. The buttons are rated for 110, so it would work fine.  However, by doing this,  there is always a possibility of a switch malfunction which has the potential of sending 110 volts through a child.  I have knocked the control voltage down to 12VDC, and suggest you do the same.

Click the image for a basic schematic of this circuit.

There's nothing too difficult with the button itself.  I connect standard 26 gauge telephone wire to each pole of the switch, and to the diode as well.  The resistor knocks down the current to the diode.  The resistor value will be determined by the current from your transformer, as well as the rating of the diode.  A diode is polarity sensitive, so it will only work one way.

As for the post, I've just hollowed out for the switch, drilled through for the wire, and attached a standard RJ-11 telephone jack to the back, keeping all buttons standard with one another.  Each jack is wired red/green (switch), yellow (LED+), and black (LED-)

All the post wiring terminates in the Bix block.  If you look close, you can see I have the LED + and -, as well as the switch DC+ daisy chained together.  The switch DC- from each relay is not run through this block, but terminates at the transformer (see schematic).

I built a box with male and female RJ-11 jacks which I use for testing purposes. When you have a trouble on this type of circuit, (and you will), you just plug into the Bix or to the post wire at the Bix, and you will immediately know which direction the trouble is.  If it is outside, the same test can be repeated at the post to further determine the fault location.

The wiring from the Bix block and the 110VAC enter this box, and the 110VAC to the outlets leave.  I have 3 separate power feeds to these relays.  Again, see schematic.

You can see to the right of the outlets, I have also wired test circuits in parallel to the buttons.  These work off the same transformer, and replicate pressing a button.  Basically, it's no different than using the test box, but it allows me to turn a circuit on and leave it on. So bottom line, when a fence button is pressed, the corresponding outlet will work.  110VAC is switched in the yard, and only 12VDC has been controlled by the spectator, making it very safe.

With basic electrical knowledge, you shouldn't have a problem building this.  I may have omitted something, so please email me if you'd like anything clarified.