Brett Davis of Legacy Circuits, Inc and contract engineer for PCB Solutions, continues to write about his perspectives onDesigning & Manufacturing Custom Fabricated Electronics From Conception to Market. Part one of this series can be found on PCB Solutions Blog

One of the first challenges in this project was the lack of documentation on the components that I had no control of. When a lay person thinks of solenoids, valves, pumps, etc., they generally think they just work; no big issue. The box says it is a 24V solenoid valve, it just needs 24V, or the pump has a 12V starter, then just provide 12V, you all know the drill.

As a designer, we need more information. So after we signed the agreement at the price agreed upon, the customer and I engage in the following discussion:

ME: “Where can I get the documentation for the solenoids, valves and pump”

Customer: “You don’t need any documentation. It is a 24 volt Y-valve, 12 volt solenoid, and just a 12 volt starter on the pump. We may be able to get a 12 volt Y-valve, but we rather use the 24 volt version because of cost.”

ME: “Voltage is only part of the equation. How much current does each of these devices require to operate?”

Customer: (crickets chirping)

ME: “Okay, can I get some of these parts to get the information I need?”

Customer: “Sure, we can get you the information you need to buy what you need.”

ME: “Fine, who do I give the invoice to?”

Customer: “Aren’t you paying for them? Wasn’t that included in you pricing?”

The conversation continues in a similar fashion for all aspects of this project. What did I get into?

After a week going back and forth with the customer on the finer details and component issues, we added an addendum to the contract stipulating they would cover the industrial component costs (valve, solenoids, etc.) whereas I would cover the embedded component costs needed for development. At this time all of the main embedded components were also defined and accepted by the customer, so with all of the hardware now specified and available, the real development could begin.

The lesson learned at this point was to DEFINE who was responsible for providing what components, and get the details of the components at the time of the quoting process rather than after. Some design changes were needed once I learned about what I was dealing with which had some small impacts on the schedule, but I was able to overcome the challenges.

The adage “The Devil is in the Details” is very true here. I unfortunately made several assumptions based on my experience with solenoids, relays, and motor controls, which were all wrong in this application. Also, the expectation of the customer was that I would know all aspects of his industry or at least the basics, just as mine was he would understand the basics of mine. We were both miles away from understanding the reality of what we would be attempting, but patience on both of our parts brought about a common vision as to the direction we would be going.