Prototyping with Modules

Developing a new application nowadays is often done with a modular approach as a first step.

And this can be done in many ways.

As a first proof of concept, it is quite common to just use a solderless breadboard and jumper wires. Ideas can be tested out very fast. Changes are done within seconds, and without any additional tools such as a soldering iron. Through-hole technology devices are widely available either as single components, or in kits for parts such as resistors, capacitors, and many other electronic components.

Figure 1: Solderless breadboard and jumper wires (922327-ND). (Image source: Digi-Key Electronics)

Additionally, the broad availability of modules for different functions like accelerometers, gyroscopes, and wireless connectivity, is making it easier to use the breadboard for more complex projects.

Using SMD components when no module is available is still tricky for breadboards, but it becomes possible with these adapters. The adapters transform a SMD component into a through-hole device which can be used with breadboards. The adapters are available for a broad variety of SMD packages, starting from different SOT packages, over a variety of SOP and QFP packages, down to BGA packages. There are even adapters available for different SMD resistors or capacitors, and different connectors like micro USB or microSD cards.

To get a prototype to be more robust in comparison to a breadboard design, it’s possible to adapt the project to a perforated board, which are available in different shapes and sizes. By simply connecting the devices with some hook-up wires and soldering the devices and wires to the board, the prototype is ready to be demonstrated.

Another approach might be to use one of the different available expansion boards such as an Arduino shield, Raspberry Pi HAT or BeagleBone Cape. A big advantage of these platforms is the broad availability of information and variety of projects released with it. Still, there are some things to consider when using these standardized extensions.

Figure 2: TQFP/LQFP80 to DIP adapter (PA0110-ND)

For example, the Arduinos and clones have a clearly defined header pinout, as well as readily identifiable pins for the power supply and ground.

However, the secondary usage of some pins for I2C can cause issues. Some processors used have the I2C as a secondary function on analog pins, some on digital pins. Additionally, some Arduinos use a different logic voltage level of 3.3 V instead of 5 V. Also on the Arduino, there is a header pin available to identify the used logic level voltage.

While all the different Raspberry Pi SBCs (exempt of the retired A and B models and the compute module) feature a compatible 40 pin header, this may be an issue with some clones. General compatibility is normally a given, but secondary functions might differ.

This, however, is not a major issue. It just means that shields, HATs, and other expansion boards might not always be 100% compatible with related MCU boards or SBCs, and it’s important to check the pinouts between the modules being used.

If a matching set is selected, building a prototype with these professional build extensions can save a lot of development time. Software examples, tutorials, and videos are usually provided, and technical support is often available. At the very least, it’s possible to get support from the various communities.

All of these approaches help to reduce the time to market by making the proof of concept and prototype phase faster, which saves time for concentrating on other aspects of the development process.

About this author

Image of Michael Marwell

Michael Marwell is Manager, Digital Technical Marketing for Digi-Key in EMEA. He started his career after his German Dipl.-Ing. (FH) as a Hardware Development Engineer for Access Control Systems, followed by different Application Engineering Roles for Suppliers and Distributors. In his free time, he likes photography and tinkering with electronic devices.

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