Tag: Arduino

LED Microscope Lights

I have owned this stereo microscope since I was a teenager. At first used for examining rocks and minerals in my collection, it has found many uses over the years, mostly used during assembly and inspection of various bits of electronic gear. It has been a workhorse microscope, well used, and well loved.

An American Optical model 40 stereo microscope
An American Optical model 40 stereo microscope

Despite this it bit me!

I know the feeling all too well, that little 60Hz nibble of 120Vac electrical power, a feeling anyone who has worked with electricity like I have recognizes instantly. Somewhere in this microscope 120Vac power is shorted to the frame.

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A Gas Modulator

The usual drill… A problem that can be solved by a bit of circuitry. In this case the gals in the lab were having trouble controlling the mix of gas to their cultures. They needed to feed much less CO2 to the mix, where the off-the-shelf flow gauges and needle valves became difficult to use much under one liter-per-minute.

Gas Modulator
A controller to modulate CO2 into a laboratory gas mix

Simple solution… Build a gas modulator, something that could turn on the gas some percent of the time, allowing easy control of small amounts of CO2 to the mix. A timer and a gas solenoid… Easy.

There is nothing particularly interesting about the circuitry. A seven segment display, a few switches, and a power transistor to control an external solenoid. All very basic. It is the controller that is new, at least for me. An Arduino provides the programmable part of this project.

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