Das zweite Türchen

The products behind the doors of the advent calendar have been carefully selected and placed in a certain order. Since the first electronic experiments are best carried out on a breadboard, the breadboard (see Blog of 01.12), in the world of makers you can't avoid occasionally reaching for the soldering iron.

However, before soldering the pin bars to an expensive Micro Controller or Display as a beginner, you should make your first experiences on a simpler and cheaper object. That's why I first practiced before I soldered the pin bars on the difficult WiFi LoRa32 Board after a long break: on the DIY Christmas tree Kit with many resistors and LEDs as well as some capacitors and transistors. At this point I would like to share my experiences.

My Equipment


You shouldn't save on the soldering iron, but for our project "soldering little legs" it doesn't have to be an expensive, adjustable soldering station. For soldering tin, I prefer the thin wire with a diameter of 0.56 mm. By the way, Solder is usually a tin-lead alloy whose melting point is between 180 °C and 260 °C and thus lower than that of the main components. Rosin is added as Flux. Do not inhale fumes. Suction devices must be used in the professional sector. I blow away the fumes during the soldering process.

Once something has gone wrong or a defective component has to be removed, a desoldering pump is required. But don't expect too much: you can't desolder a complete pin bar with it. It works best if you can pull out the component after heating the solder.

The blue part on the left in the picture is a bending aid for Resistors, etc., And the flat-nose pliers, we need to cut off the excess wire of the components after soldering. On a wet sponge you can occasionally clean the soldering tip (the cheap household sponge is not really suitable). And the left sponge comes into play if we want to fix the components on the board before turning them over for soldering.

Our Test Object


The two boards of the Christmas tree are still on top of each other. They are different because they end up being put together.


It is very helpful that the two boards are printed with symbols and labels. There we assemble the components to solder them later on the back.

We start with the resistors for two reasons: on the one hand they are flat and do not stand in the way of the other components or the soldering iron later, and on the other hand they are the cheapest components. Each board has three resistors a ' 1 kΩ (KΩ=kilo Ohm) and 10 kΩ, only one board has an additional 2.2 kΩ resistor.

Description

Value

Ring 1

Ring 2

Ring 3

Ring 4

R1, R3, R5

10 kΩ

Brown

Black

Orange

Gold

R2, R4, R6

1 kΩ

Brown

Black

Red

Gold

R7

2.2 kΩ

Red

Red

Red

Gold



There are two tricks for temporary fixing: first, bend the wires outwards after plugging them in, and second, fix the components with the kitchen sponge before turning them over.


Now it's getting hot! Please touch the soldering iron on the handle and heat the wire of the component with the tip. Then hold the solder wire from the few centimeters unwound roll of solder against the wire until enough solder has flowed. First remove the solder, then the soldering iron. Review result. A small cone around the wire? Hole closed on the board?

All good. And if not - we still practice and still have a lot to do. So that the long wires do not interfere further, they are taken off after soldering.

Trick question: Have you plugged the resistors in the right way? It does not matter!

But watch out. Polarity is important for the next components. We want to solder three electrolytic capacitors on each board. Electrolytic capacitors have a significantly higher capacity than "normal" capacitors of the same size, but therefore, it is essential to pay attention to Plus and Minus. On the board we see a shaded field and a free field with a small plus sign at the respective places.

On the component itself we see two legs of different lengths (as we also have on the LEDs) and on the housing on the side of the shorter leg see a white bar, the oversized minus sign. When bending, remember that the capacitor should be flat on the PCB.


Three transistors each with a round and a flat side are printed on the board so that you can not do much wrong when plugging in. But please do not use force. The housing remains at a small distance from the board (see rear Transistor) due to the distance of the holes.


Now it goes to the 18 LEDs per board. As noted earlier, LEDs are also components with polarity. The longer leg is again the positive pole, called Anode. And the shorter leg is the negative pole, called cathode. On the side of the cathode the housing is flattened, but with the small LEDs you can hardly see or feel it.

The LEDs are plugged in so that the longer leg is inserted through the rectangular solder pad and the shorter leg through the round solder pad. All cathodes point to the tree top.


While plugging through, I noticed that the LEDs can be pushed through the holes with a little pressure due to a small thickening on the legs. In this position, the LEDs can then be bent perfectly outwards. One last inspection-the shorter legs point towards the tip – and off we go. And while we are doing so well, the switch and the small power socket are soldered to the base plate.

In the end, it gets a little more fiddly if you don't have a helping hand. The two boards should be pushed into each other and then soldered with the base plate, i.e. in the right hand the soldering iron, in the left the soldering tin, but who holds the boards tightly on the base plate?

I pulled the two parts apart again and fixed one with a rubber band. Please also pay attention to the polarity here. The power supply of the Christmas tree lighting is provided via the base plate.


Then insert the second PCB with correct polarity and solder with the base plate. Ready? Not quite yet. Finally, the LED for the tree top is soldered. Who opts for the supplied USB cable as power supply, is now ready. Otherwise, the supplied battery holder for three Mignon (AA) batteries  is fastened under the base plate with the 2 screws and nuts and the 2 wires, correspondingly shortened, soldered.


I wish you a lot of fun with your soldering project and with the slightly different Christmas decoration.


Specials

6 comments

Bernd Albrecht

Bernd Albrecht

@ maurilio fiorito: Unser italienischer Freund hatte uns auf einen Übersetzungsfehler im IT eBook aufmerksam gemacht. Danke dafür. Wir haben den Fehler korrigiert.

@ Heinz Köppe: Die von Ihnen gewünschten Angaben finden Sie im Datenblatt auf der Produktseite. https://cdn.shopify.com/s/files/1/1509/1638/files/DIY_Weihnachtsbaum_Kit_Datenblatt.pdf?6283934366688661570

Heinz Köppe

Heinz Köppe

Wenn ich etwas baue, sollte es nicht nur die Geschicklichkeit fördern, sondern auch das technische Wissen erhöhen. Dazu gehören nähere Angaben über die Bauteile. Was sind das für Transistoren , wie belastbar sind die Widerstände usw.. Wie können LED mit nur zwei Anschlüssen drei Farben anzeigen und eine Erläuterung der Funktion der Schaltung wäre auch interessant.

maurilio fiorito

maurilio fiorito

forse ho sbagliato qualcosa, ma tre alberi su tre hanno accesa solo la punta. Il book però scambia la saldatura dell’anodo con il catodo, quindi ho saldato tutti i led al contrario?

Franz Twelsiek

Franz Twelsiek

@Straube SO ENDSTEHEN WAKELKONTAKTE; NACH 48 JAHRE SISTEMELEKTRONIK WEISS ICH WOHL WO VON WIR ELEKTRONIKER REDEN. OFFENER KUPFERDRAHT DARUM ZINN & DANN LUFTFEUCHTIGKEIT NACH DREI JAHREN KÖNNEN SIE DAS BAUTEIL RAUSZIEHEN !

Daniel Straube

Daniel Straube

super erklärt und schön dpkumentiert.. ist mal gelungen. @twelsiek : das mit dem abschneiden vor dem löten finde ich schwachsinn und hab ich noch nirgends gesehen

Franz Twelsiek

Franz Twelsiek

Ich habe gelernt, den Draht vor dem Verlöten abzukneifen als Schutz für Korrosion zwischen Kuper und Zinn.

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