Alto Aviation Capacitive Touch Control

Capacitive Touch - Uniform RGB Lighting

Project Description

It all starts with a phone call. We have customers that call us from all over the world!

The goal of the first conversation is to determine exactly what the customer is looking for. We use this information to come up with a design plan. This design plan details the look and finish / materials to be used, type of communication protocol that will be implemented and the methods we will use to build it. The most important piece of information that starts the conversation is a sketch of what the customer is looking for. This could be a detailed drawing or a simple napkin sketch.

Our customer was able to provide us with a beautiful rendering of the touch keypad assembly.

With this drawing we could now have a very productive conversation. This rendering allows me to think about all of the requirements, from the different color uniform lighting to the mechanical shape and thin form factor that is required. This rendering also made it obvious to us that the customer needed some type of mechanical housing to pull off the full look and feel that they are looking for. Since the electronics / graphic and lighting overlays and the mechanical housing designs all must fit together perfectly, it is very important that all of this design work is done simultaneously. Once we discussed all of the aspects of the design requirements, we put together a design plan. This design plan basically summarizes our conversation and shows the customer our true understanding of what is required for their new product.

For this project, we put together the following design plan:

1) We are going to use our PCB type capacitive touch keypad. This means the PCB will have the touch pads on the top surface of the PCB and all of the necessary electronics on the back side of the PCB.

2) The customer wants to use RGB LEDs to uniformly light the graphic overlay. This meant that we could use our LEDs that have the all 3 color (red, green, and blue) dies in one led. Doing this would save a considerable amount of space. Our lighting layer is a special laser etched or imaged layer that allows the light to uniformly glow underneath the graphic overlay. The thickness of this lighting layer would be 1mm.

3) The graphic overlay will be made so that it is scratch resistant and have opaque and translucent inks. The customer is interested in using glass or polycarbonate for the material. The thickness of this will be 0.030” or 1mm chemically strengthened glass.

4) We will have to use a special mechanical mounting method in order to assemble this correctly. Male or female PEM ( fasteners can be used.

5) The communication method will be half duplex RS-485 as well as standard low side driver control using NPN transistors.

6) A custom GUI interface will be used for the setup and demo control of these capacitive touch keypads. The customer has a trade show that they are attending in a couple of weeks and needs some way of showing all of the keypads working together as well as being able to change the colors of the lighting. This same windows application software can be used to do acceptance testing of future production keypads.

7) A mechanical design review is needed to determine the best mechanical mounting method for the different private jet interiors. A GoTomeeting ( will be conducted so that the customer can see my Solid Works 3D Cad desktop as I design different possible solutions.

8) The mechanical parts must be aluminum so that they can be polished and plated with precious metals, like gold, silver, chrome etc. We will use the FDM process for initial prototypes and then have one of our partners’ 3D print metal parts.

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