With the approach of Christmas every year I try to do something new, just that this year I tried to involve my daughter.
Starting data were:
Christmas image to put in the terrace possibly be different from those made in previous years.
The realization study that came out is summarized in the scale drawing below
an elongated star composed of eight concentric stars.
At this stage I have absolutely put brakes on his fantasy, and although I personally would have made different choices I wanted him to hear her the whole project.
The realization phase has resulted in the choice of materials, as a fundamental element support, it must be cheap and stiff enough to be self supporting.
A few days later she returned to the house with the back of an old wardrobe demolished, although the material (MDF) not suitable to go outside I decided not to make her aware of thinking how he must have shot between relatives and friends to be able to find it, I, however, imposed for "security reasons" the final covering with a sheet of transparent nylon. The cloth would protect the material from the weather and the lights from infiltration of water and would insulate the parts subjected to mains voltage from accidental contacts.
After playing the real-scale drawing on the material he has begun to drill along the lines with a tip such as to allow the insertion of the lights.
In the photo the female engineer / performer / director of the opera works while fixing the LEDs with hot glue, The photo is deliberately poor quality for privacy reasons, it was only important to the action and not the recognizability of the subject.
That is the work that she could do, Now the electronic part for me, firstly a premise, all LEDs are the result of Christmas chains do not work that I have been given away with the phrase "if you can see something overcharged so I throw them", after thanking the I set aside for the following year when they definitely come in handy.
These lights are so cheap that it's not worth losing time, given the cost should buy some new ones to make the tree.
Turn the lights Indoor specifically because their controller is easily recyclable.
Once removed from its plastic wrap and freed of the wires of the lights it appears more or less so
Small variations in the arrangement of components and in size are always possible, each manufacturer realizes how he wants.
Heart of the circuit is the integrated comb that is seen to escape on the side weldings, they are virtually identical as external connections, vary the play of light as a function of the symbol printed on the ticket.
The complete diagram is this
Four diodes 1N4007 rectifying the voltage and make button, a limiting resistor 150K He pin 10 the integrated circuit which has in its interior a Zener diode for limiting the voltage and an external electrolyte stabilizes.
A resistor 1M It serves only to detect the passage through zero in such a way as to give the internal clock and sync with the circuit network.
Almost never find all four SCR for the sole reason of saving a few pennies multiplied by hundreds of thousands of pieces give a good gain. They are normally found with only one pair of SCRs, mounted in two outputs or odd or even depending on the manufacturer, damage as a result of lower cables that make up the chain with savings in the amount of copper used and the same SCR, without giving great aesthetic differences from the end user perspective.
Missing SCR can be cannibalized from other coupons or purchased, the characteristics are 400V e 100mA .
In my case my daughter has scheduled eight independent channels so I have to use two controllers in tandem.
As up to two with four outputs I found I'm not been forced to add the two missing adding the SCR not present in schedina.
In the pictures you can see two different printed for the same circuit.
Here the particular insertion of the two SCR in question with positioning is not perfectly aligned with the other to exploit the existing runways, I also had to make two small holes to easily weld the missing outputs to the related SCR by means of small wire portions.
Once the new closed container made from an old box that I have no idea what it originally contained'm ready for connections
The end result is this
while this is what I did by himself last year with the same system
hoping that this article may be of help and stimulus for other ideas remember that the same circuits I also used them to 24V alternating taken from the transformer of a chain outer reducing in proportion to the value of the two resistors, also meeting the safety requirements where you should or want to respect them.