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Development of microcontroller based systems for science

Several projects involve the use of microcontroller systems to design new instrumentation and sampling devices. The systems are based on the open source Arduino microcontroller and the popular BASIC Stamp modules from Parallax.

Breadboard development for keypad input to underwater sampling system

Connecting solenoid valves to pump. The valves were from stcvalve.com model#2V025 and in 2014 Adafruit.com stocks valves that are better and simpler

 

MOSFETS to control solenoids

Nautilus - an autonomous reactive underwater sampling system.

Collecting samples from remote areas or over extended periods of time require specialized equipment. Much of this equipment is not commercially available so we need to design, build, and test this equipment.

Early schematics and plans of NAUTILUS - an autonomous underwater sampling system

AquaDox - Underwater Dissolved Oxygen Reader

Working underwater, we need to be able to read the values of temperature, light level, and oxygen sensors. AquaDox allows us to read the sensor values while underwater, freeing the instrument from any cables and allowing the scientific diver to react to current conditions.

Here is AquaDox connected to a benthic flux chamber in the Florida Keys. A "magic wand" is used to turn on the sensor, and also log the data that can be downloaded at the end of the experiment.

The dissolved oxygen level is displayed in real time so we know what the conditions are within the chamber and when the experiment is completed.

Interior electronics of AquaDox is based on an arduino microcontroller. An annotated version is on flickr.
AquaDox deployed on reef sand in the Florida Keys. The LCD panel is visible which displays sensor data.

Pumping volumes are displayed on the LCD and stored in EEPROM for later downloading along with an error file if generated. The actual flow of water pumped is measured usign a flow meter downstream of the pump. In 2014 Adafruit.com has a simple to interface flow meter that would work much better

The electronics including the LCD and keypad are controlled by an arduino (arduino code here) with an 8-bit shift register to extend the number of pins. Very important to decouple power and include smoothing capacitors as the pump pulls significant current when turning on

I used the "INTERRUPT" function to continually monitor for a STOP signal in case it all went horribly wrong. The entire pump was enclosed in a Pelican case 1500 with holes drilled in the sides to attach filter holders that contained 47mm diameter filters.