The internet has made circuit development from home easier than ever before. This benefits engineers in a huge way by offering a venue for them to turn their ideas into physical working reality. Regardless of whether you are independent or employed by a company, there are many advantages to developing a prototype on your own.
Did you ever have that idea that your employer scuffed about however you saw the value enough to pursue it externally? Realize that you may have signed an agreement which forfeits patent rights to your employer. If you use their software or a license that they pay for or even a work computer then you may lose all rights to the patent. For employees who want to branch out with an idea, there are many software packages that allow you to capture a schematic and then transition it into a board layout and physical prototype. Unlike the days of old where you would invest thousands for design software, many website now offer free or low cost packages for developing physical circuitry.
Having recently created prototypes, I have decided to write a series of blogs that reveal the options for development as well as to guide you through the process. This first blog introduces the subject of developing prototype circuits from home. Future blogs will elaborate on the subjects introduced in this writing.
The story is told from the power circuit point of view however it is applicable to many types of circuits. Power is typically more intense from a physical aspect as well as for heat dissipation thus making layout a bit more challenging. Also, power often requires the development of custom magnetics. These complications make power a good subject for turning the virtual into the physical.
As an independent engineer or hobbyist who desires to create a working prototype, your options are not limited as much as they once were. The industry has provided flexibility in development software as well as physical prototype board development. This allows you to develop a concept into a patentable product. You can also produce working prototypes for clients who purchase your engineering skills. This process can all be completed via your keyboard over an internet connection.
Prototype development breaks down into several different sections. There is the schematic layout, board layout, and physical production.
Schematic development is well served when coupled with an evaluation software. This allows you to test run the circuit from a virtual perspective prior to spending hours building it only to discover it doesn’t’ work. Simulation software also allows you to overstress components without destroying them.
Several semiconductor manufacturers have developed online tools for schematic development and electrical evaluation. Some manufacturers such as Fairchild  and Texas Instruments  allow you to work online. Others such as LTSPICE  require you to download software. This is an advantage as you can continue to develop in the absence of an internet connection.
These evaluation packages hold value for the supplier as well as the customer. For the supplier, the software uses models based on its products. This encourages you to use their parts. For users, nobody knows the product better than the developer. The models are based on actual laboratory development and test data. Other options include the ability to use existing development boards or create a custom board to meet your needs. Furthering these packages is the ability to develop magnetics and board layouts complete with Gerber files. These services were outlined in reference .
Although readymade solutions are available through manufacturers, there are many times that a custom circuit must be made. The discussion now focuses on custom designs that require you to create your own schematic, choose your own components, and lay out your own board. In some cases you may also have to develop your own custom components such as magnetics. For this discussion, a model has to be developed for a spark gap in order to simulate an automotive ignition.
Board layout is the next phase of development. Electrical circuitry as depicted on a schematic is far different from the actual physical prototype. This is why it is important to have a connection between the electrical schematic and the physical board. National Instruments has developed a schematic layout and evaluation tool known as Multisim . This package transitions easily into their board layout software Ultiboard . Other board layout software packages are available from Eagle and Altium. Board software for “Fred in the Shed” home developers will be covered in more detail in a future blog.
Physical production of a circuit is where the rubber hits the road. Virtual simulation can only take you so far. A working prototype offers the ability to measure the circuit. This provides insight that goes beyond the limitations of physical models. Customers often desire a physical model. There are board stuffing services that save you time and money in development. If you use parts that they purchase in large quantities, you may receive a discount through them. Other services require advanced kitting of parts.
In order to create a working circuit, a physical board must be populated with components. This has created an industry of board makers and stuffers that cater to the smaller volume market. The market has gone worldwide. Prototypes can be turned in a matter of days due to electronic data transfer and overnight shipping. The process is not always a smooth one. Therefore, the discussion requires a more specific blog relating to this process.
The subject of physical prototype development involves several aspects including schematic development, board layout, and physical production. Each of these subjects has been introduced at a high level. Future blogs will go into detail on each subject. The goal is to relate the experiences of creating and receiving a prototype so that you can turn your patent into a reality or maybe just have the coolest hobby based circuit. From a personal standpoint, writing outside of my career improved my skills as an application engineer. Having a defined goal to create a prototype circuit will give you a reason to learn a new software or design technique while improving your engineering skills. It also gives you a skill to fall back on between times of employment. Who knows, it may eventually free you from cubicle life where you too can design circuits as deer prance by your window.
- PowerEsim website
- SMPS Power Design
- Ridley Engineering Power 4—5-6 software design
- Fairchild webdesigner website
- SwitcherPro(TM) Switching Power Supply Design Tool
- National Instruments Multisim schematic design and evaluation tool
- National Instruments Ultiboard board layout tools
- You Need a Power Supply Designed by When?