Many projects are never really done. Sometimes it’s because they never really worked right to begin with. A lack of money, time, or brainpower (although rarely admitted) is usually to blame. Other times, you’re compelled to revisit a project you thought was finished because new technology makes it possible to improve upon your design. We have a couple of great projects this month that are the result of redesigns.

Charlie Krauter went back to the drawing board to correct the problems that made his undergraduate senior project come up short (p. 12). He intended to build an efficient liquid piston steam engine based on a computer model that would pump water using few moving parts. When it failed, what bothered him the most was that he couldn’t figure out why it didn’t work. Charlie decided to build a low-cost supervisory control and data acquisition system. His CAN bus system turned his project into a success.

In “Intelligent Sensor Head,” Andrew Smallridge discusses how he redesigned a Bowen ratio data acquisition system to offer better stability and accuracy (p. 60). He was inspired to revisit the temperature sensor conditioning and acquisition subsystem by the introduction of inexpensive, high-performance analog building blocks. Moreover, he kept the overall cost in check because he didn’t need a hardware development platform and he used free software development tools. The project is built around a Maxim MAX1463 signal processor and a Microchip PIC18F252 microcontroller. The result is impressive.

Larry Cicchinelli had similar results when he went back to work on a previous logic analyzer project (p. 54). This month, he walks us through the design of his new eight-channel, single-board logic analyzer (SBLA). He set a tall order to fill; the most significant goal was to fit all of the circuitry on a single PCB that would be easy to build. Larry met his goal, and the result is a hard-working piece of test and measurement equipment that’s a must-have for anyone who deals with complex digital circuits.

Even when you say you’re finished with a project, chances are you’ve already made a mental list of potential upgrades. These designers have shown that a redesign can yield big results. To borrow an oft-repeated sentiment from Tom Cantrell, as long as the march of silicon keeps up the pace, just about any project can be improved upon.

jennifer.huber@circuitcellar.com