You only need one thing to design your own Lego GBC:
1. Have an idea… or…
2. Find ideas. Where? In the industry, mechanical machines or ,why not, other GBC’s, take the mechanical rule and try to improve them. You can take some ideas here, here and here. All finished GBC modules around the web can be found in the LEGO GBC mudules index.
If you are new in the LEGO GBC building kind of thing, I strongly recommend to first rebuild some GBC modules form other creators. Here you can find and download some building instructions of LEGO GBC modules.
3. Always try before you start to understand completely how your idea will work and to make a mental picture of what you want to build. It all must be very clear so the solutions can be easily found. Build “like crazy” is not the best way to assemble a module, in fact it is almost impossible. Another thing is that a discarded mechanism from another site inspires you, and you know how it works and you’ve spent time working on it. Finally, keep in mind your parts availability.
4. Now it’s time to finally get down to work, always keeping well clear the basic parts of a module and its requirements. On the “What’s a LEGO GBC” page you can find the original requirements.
5. This requirements can be summed up in:
5.1 The transport speed of balls is one ball per second, and in groups or batches are transported by no more than 30 at once.
5.2 The height of the balls input to the module is 10 bricks high, a taller input height makes the module assembly difficult at an event, drastically reducing its compatibility.
5.3 The height of the balls output of the module is 10 bricks high, a lower output height limit their possible connection to other modules in an event. If the output is much higher, a drop system for the balls is recommended so they fall in a “civilizated” way.
5.4 The input container must have an approximate measure of 10 x 10 studs, measuring the inside at least 8 x 8 studs. Otherwise it will be difficult for the modules to hold 30 balls, which is the maximum that can be received at once (batch).
5.5 It’s convenient but not required to use a 9V motor compatible with the Power Functions system and the trains electricity transformers. To use the transformer with a PF motor a converter cable is needed.
5.6 Although not obligatory, it is highly recommended that the modules respect the dimensions of the original standards, ie using 32 studs long baseplates and its multiples. This makes much easier the connection between the modules.
6. Where to start? Well if point 3 is clear enough you will have a mindset and an idea of the most critical and will laborious parts of your module. This critical and laborious part is, almost always, the transport system, usually mobile. But first we will divide the module in parts for a personalized plan of attack to each part of our module.
6.1 Input Hopper: It may take the form of box, ramp, cockpit, corridor. It is the part which have to be able to store the batch of 30 balls. It is very important to fulfill the rule of 10 studs high so your module is compatible with that of others.
6.2 Output ramp: It may be from a slide, a tunnel, some tiles or even that the module has no piece exclusively for this function or you have gathered a structure dedicated to it.
6.3 Chassis: All GBC are usually supported with a series of pieces to the baseplate or table. These parts form the chassis or body of the GBC and ensure its structural integrity.
6.4 Mechanism: Very simple or very complex, it is the set of parts which come into contact with the balls or other movable parts whose function is the transport of the balls. According to the complexity of the module there may be several mechanisms which together form a subchassis which we will call system of transport.
7. Once the parts of our module are clear and the requirements to be fulfilled by each one are done, we can start building. We will take, as the default procedure, the one that is usually more logical and effective in most modules:
Design and implementation of the mechanism > Chassis > Input Hopper > Output System.
Once the mechanism is created, and surely many versions later, place it into the chassis or built the chassis around it, so that you can ensure that both input and output systems can be built with the correct height and the balls enter and exit the module correctly.
8. General recommendations for the construction of the module:
8.1 Try to be aware of all your pieces and always have the balls near you for testing
8.2 Never forget the rules or think the process will not be difficult. Do not let any aspect to the randomness thinking it would work.
8.3 Do not despair, alternate your work on various projects, whether other modules, modular buildings, cars or even something that is not Lego, wich allow you to free your mind.
8.4 Do not get frustrated, think that satisfaction is greater if the design and construction process has been hard.
8.5 Do not be lazy to dismount if you know how to improve one part. A modular design will help you in this task. That is one of the biggest secrets to make things work.
8.6 Do not ever think that everything will turn out right the first time.
8.7 Expect the unexpected, the balls are very capricious
8.8 How much you try a module will never be enough, so before thinking it is done get bored viewing how well it works becouse in the event it may not work…
8.9 You have to be very patient.
8.10 Give yourself time to the project, the rush is not good, if you have the module unfinished for two weeks in your work table, the most unexpected moment you can have a happy thought to let you finish it in a while. If you are 24 hours above him you may not find the solution.
8.11 The cavities, voids, “blind spots” and other hiding places are not your friends. The balls are hidden there. This is especially important for the mechanical parts of the modules. If a ball goes in them it can block the entire module and even break some parts. Make sure that balls can not be cast in any site to the mechanisms or below the module. The module does not have to work alone for a while, it has to make thousands of cycles, so ensure reliability is your mission.
8.12 Never think the recommendation 8.11 is fulfilled. 8.7 tells you.
8.13 Use an appropriate speed; a slow module will collapse all the Lego GBC circuit and its container will be saturated. A very fast module is usually unstable and ,on failure, balls can be shooted out far. Ask yourself that the motors have the combination of appropriate gear ratio for use at full power (9V)
9. Once you are happy with the performance and reliability of your module, have met several times the recommended 8.10 and after several redesigns, optimizations and improvements, it is the time to think about the aesthetic qualities and/or the theme, color, replacing parts or decorations covered.
10. Take your module to an event to be part of a circuit.