Build a Simple Dedicated Tester

Whether you’re planning a small controller for your own use or an electronic device for mass production, you need to keep “testability” in mind. So, it’s a good idea to make a dedicated tester for your product part of its initial design.

Such a tester can ensure your device is functioning smoothly in your workshop—before it ships to a customer.

A dedicated tester (with the white panel) simulates inputs and loads for an embedded controller. A breakout box (with the red terminals on the panel) allows access to every interface line.

In the upcoming May issue of Circuit Cellar, columnist and engineer George Novacek discusses how to build a simple and inexpensive dedicated tester for a product.

“According to old engineering wisdom, every new project should begin with test design,” Novacek says in his column. “If you don’t follow this advice, your product may have features that are too awkward, too time-consuming, or impossible to test. You always need to keep testability in mind. Ultimately, it improves reliability, reduces manufacturing cost, minimizes field returns, speeds up production, and reduces the cost of repairs.”

Engineers certainly have access to a broad range of general testing equipment, from oscilloscopes to signal generators and analyzers.

“While these instruments are sufficient for testing, working with them solely may be slow and cumbersome,” Novacek says. “Imagine an embedded controller with a number of input and output devices, all of which need to be monitored while different signals are injected for the test. That’s where the dedicated tester comes in. Companies with deep pockets can purchase various types of automatic test equipment (ATE), but this may be too expensive for a small operation. Or, it may not be practical because of the complex setup for a low-volume production. Building a dedicated, inexpensive tester can solve the problem by ensuring an efficient and repeatable test.”

Check out the May issue of Circuit Cellar for more of Novacek’s guidance on why and how you should build a dedicated tester.

Novacek plans to continue examining product testability in upcoming issues, addressing topics that include the design of hardware and software that enables a product to be efficiently tested.