I was looking at some photos and realizing how much perfboard I have used in recent years. I routinely find myself building small circuits, and that process almost always begins with grabbing a bit of perfboard from the supply stash.

Perfboard Construction
Hand wired point-to-point wiring on perfboard
Perfboard is the basis of point-to-point wiring and has been around since well before I started in electronics as a young teenager. It is generally a small circuit board with holes drilled in a 0.1″ grid.

The holes are usually about 0.042″ and will accommodate a wide range of electronic components without modification. Cheap perfboard will have no copper pads or traces, good perfboard will have a pattern of copper traces and pads to which you can solder your components. Better yet is perfboard with plated-thru holes and pads on both sides.

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Taming a Rotary Encoder

The rotary encoder is a popular input device for many microcontroller devices. A knob that can be used to increase or decrease a setting with a nice tactile click for each increment. You can even get an integral pushbutton, just rotate for the setting then press the same knob to enter. With some clever programming you can create a one device user interface using only the encoder.

GenPIC Development Setup
The development setup in use generating the first software release for the GenPIC utility PCB

I have integrated a rotary encoder in the GenPIC utility board. With the combination of an LCD display and the rotary encoder you have all the ingredients for a functional user interface arranged neatly for a panel mount unit.

In the past I have simply set an interrupt to fire on the edge of one channel, then sampled the opposite channel to detect the direction. With the addition of a small delay to debounce the result. This worked well in previous devices, but this time I encountered trouble, the direction sampling was erratic, the value going up when it should have gone down and vice-versa.

Breaking out my logic analyser I found out why, this particular encoder proved to be somewhat noisier than I had seen in the past, with notable periods of bouncing signals.

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