Since all sorts of spare parts and components accumulate over time, you should use small sorting and
storage boxes right from the start in order to keep track. This allows, for example, LEDs of all types with
3.3 V / 5 V, a diode or even a resistor assortment stored clearly. In order to carry out the Lego projects in
this book, you need, in addition to various LEDs and resistors, one or the other servomotor as needed to
drive or steer the in-house vehicle.
These are accompanied by paper adhesive labels and for holding cable ties in various lengths, adhesive
and insulating tape, heat shrink tubing in various sizes and superglue for labeling. For mechanical
connections you will need soldering and soldering wire but also occasionally threadlockers or screw /
luster terminals. In order to accommodate small parts such as LEDs, diodes, cables, etc. within Lego
blocks, it is sometimes necessary to use a (cordless) drill, mini-cutter or, better, a dremel, with which the
plastic stones can be easily processed. If the electronic components are to be firmly fixed with the Lego
module, a small drop of adhesive from the hot glue gun, which should not be missing from a well-
stocked electronic tool box, usually helps.
Self-made LED lamps
A Lego railway without lighting? Unimaginable for the advanced Lego engineer in the nursery. Lego itself
offers here a simple Aufstecklösung for the connection to the Power-FunctionSteine on
(shopAego.com/de-DE/LEGO-Power-Functions-LED-Lichter-8870, 7.50 Euro), which are mainly for the
Lego Railway models 7939 freight train. 7938 passenger train and 3677 freight train with diesel
locomotive are suitable. The problem with the whole thing, however, is that these LED power functions
are not available in the Lego shop despite a long wait and instead can be found at horrendous prices in
the Internet department stores. If you do not feel like paying more than double the Euros for such LED
bulbs in your Lego models, the LED bulbs simply build themselves. The easiest way to make Lego bricks
and Lego models with a home-made piece Connecting electronics is the installation of one (or more)
Control and dim LED diodes
For the control, ie the switching on and off or even the dimming, the LED diodes are all possibilities of
the electronics available: They can be operated manually, for example by a simple switch or
potentiometer as well as by a microcontroller in the form of an Arduino or a Raspberry Pi. Both shine
through a wide distribution in the Maker world and also provide sufficient interfaces to the outside
world, by means of which you can control the circuit.
In the example below, you either use the pins of the GPIO interface of the Raspberry Pi or the
connection rows of the Arduino to light up the LED diodes installed in the Lego brick. In addition to the
microcontroller, you only need a few things:
- LED diodes
- Board / Board
- Wires / connectors
All components are part of the basic equipment, if you want to deal with electronics. Most of these are
conveniently available in electronic basics that bring the most important things, such as multiple LEDs in
different colors and resistors in different sizes. Depending on the intended use and Lego model, you will
need a certain number of LED lamps and, depending on the desired color and voltage supply, the
appropriate number of suitable resistors.
No matter what color the LED diodes used have: diodes only allow the current in one direction, and
therefore the insertion direction in the circuit must be correct. The LED diode is known to have two
terminal legs that are of different lengths. The longer part is the positive terminal, which leads to the
power supply (3.3 V) or to the switching pin – the shorter leg is led towards ground (0 V) and provided
with a resistor. Since the current is limited by the resistor, a resistance of the order of 200 to 300 Q is
sufficient in this example. If the LED is to be permanently lit, it is connected to a constant current source:
In the case of a Raspberry Pi, connect the positive terminal of the LED directly to pin 1 (3.3 V), the wire
from the resistor is connected to pin 6 (GND, ground) connected. If the LED diode is to be switched via
microcontroller instead of the switch, use one of the available GPIO connections instead of pin 1 (3.3 V).
The Arduino also has its own pin connections for the power supply – should the LED be switchable.
Lego Modding with Drill and Dremel
The implantation of smaller circuits such as an LED traffic light should not be a problem for the
inexperienced because of its compact design – if necessary you will initially use an additional Lego
module for the test in order to practice drilling machine and Dremel handling. Basically, the optically and
technically appropriate Lego module must first be selected for the installation of electronics of all kinds.
Anyone who does not immediately find the right stone in his Lego box can, as you know, also go on the
Internet on the search.
After selecting the desired module, it must be determined exactly where the electronics – for example
an LED – should be installed. So that the necessary for the operation of other components, such as
connection cable, series resistor, etc., can also be accommodated in the selected block, it is usually
necessary to previously edit the block mechanically. In this case, a file, a rasp or a scraper blade for
machining barely sufficient, the ABS plastic (acrylonitrile-butadiene-styrene) is very stable and resistant.