Thermal fishing bob

This variation on the [thermal flashlight](/tool/thermal-camera) uses a cheaper **thermistor** instead of a non-contact IR thermometer ($20), but can only detect the temperature of things the sensor is literally **touching**. ## Questions [questions:thermal-fishing-bob] ## Activities [activities:thermal-fishing-bob] **** The circuit looks like this: Read here for build instructions by Sophia (RISD), using a thermocouple taken from a cheap medical digital thermometer: ![in-bottle]( Here is one, assembled: ### Concept The idea is to put this in a waterproof container with the the thermistor poking through the outside (but not letting water in) and to "cast" this into a waterway while taking a long-exposure photograph. This will create a "light painting" where the colors describe the temperature of the water at that location. Eymund Diegel has been doing some good sketches of this, focusing on a version where you drag the package around on the bottom of the canal, but the light is on the surface of the water (this will allow mapping of bottom temperatures, but will require more waterproofing). ![eymund-sketch]( **** (The following was copied from [the thermal photography page](/wiki/thermal-photography) and should probably be [posted as an activity](/post?tags=activity:thermal-fishing-bob&title=Build a DIY "thermal fishing bob"). The thermal fishing bob project develops a DIY technology to visualize changes in water temperature, which can [indicate water pollution via industrial sources]( or [sewage]( The fishing bob is designed simply enough that anyone can build it and its components can be easily obtained from Home Depot and Radio Shack. ### Project Goals: To produce a cheaply made, easy to use piece of technology to track temperature changes in water. And to produce a product that can be easily altered to suit many innovative needs. ### Research URL’s: First iteration of the Thermal Fishing Bob developed in Sara Wylie’s class at RISD: Second iteration of the Thermal Fishing Bob developed at 2014 Barnraising: First long exposure pictures with the fishing bob: [First Field test of the Fishing Bob]( [Research Notes on development workshops MIT]( [Barnraising]( [Northeastern University]( [Research notes on towing the tool]( [Next steps on developing the tool]( ### Building Your Own #### How To Guide ThermalBobHowTo.pdf The fishing bob’s tech is sealed within a waterproofed translucent container, a Koolaid mix container will do, with only the thermistor poking out the bottom (sealed around the edges with hot glue). The fishing bob is then wrapped in foam so that it floats, attached to a reel so it can be pulled, and dropped in the water. The thermistor reads changes in temperature and the LED within the fishing bob causes the fishing bob to change color in accordance with the temperature. The readings are recorded on the Arduino inside, which can then be read once it is plugged into a computer. While the fishing bob is being dragged across the water long exposure photos are being taken to create a “light painting” of the temperature gradient. One neat way to make these long exposure images is to use [glowdoodle]( from MIT. ### Materials * translucent plastic containers that can be easily sealed for waterproofing such as a takeout soup container or Koolaid mix container * 9 wires * [thermistor]( * [breadboard]( * [Arduino Uno]( * [3 Color LED]( * 9V batteries and holder * [2 100 Ohm resistors]( * [1 180 Ohm resistor]( * [1 10k resistor]( * hot glue gun * packing tape * wire strippers * scissors * small flathead screwdriver * foam * fishing/kite reel * [Arduino to USB cord]( * computer ### Thermal Fishing Bob Arduino Sketch ### Next Steps: I am currently working with Sara Wylie on a project to make the thermal fishing bob towable behind a kayak. In previous testing the fishing bobs tended to submerge and become water damaged so we are working on a prototype that would be set into a floatation device. One concept is to wrap two fishing bobs in foam and set them into the legholes of a child’s floatie, duct taping them into place. The first test was successful, the fishing bobs stayed in place above the water and there was no noticeable water damage. A second idea is to attach three fishing bobs to a foam sled/boogie board with thermistors of differing lengths to take a 3D image of the thermal gradient. This idea has yet to be tested. A third idea is to utilize ideas from the coqui to transform the thermal fishing bob into a conductivity fishing bob. This idea is still in the brainstorming stage, but we will be building a prototype soon. ### Images [![Untitled.png](]( Thermal plume along the Charles River [![Screen_Shot_2015-05-05_at_8.32.34_AM.png](]( Fishing bob made at MIT workshop from a soda cup [![Screen_Shot_2015-05-22_at_7.20.43_PM.png](]( Thermal fishing bob circuit [![Untitled3.png](]( Fishing bobs ready to go [![Screen_Shot_2015-05-12_at_5.59.31_PM.png](]( Fishing bob being lowered into the river [![Screen_Shot_2015-05-12_at_6.00.36_PM.png](]( [![Screen_Shot_2015-05-04_at_4.44.30_PM.png](]( First prototype of towable fishing bob **** ### Arduino code ### Updated Arduino code from 2013 Barnraising ...

Author Comment Last activity Moderation
samrider "@sekjal. I was amazed by the use of Lego. I wanted to ask you if it was possible to make a wall riding car similar to one shown by @Mathew or this ..." | Read more » about 5 years ago
lperovich "Here's a picture of one of the riffle-ish boards (currently called "fishnet"): " | Read more » over 7 years ago
warren "Ooh, i love the christmas tree ornament; didn't know those were available in plastic: Do you have some pics or plans for the riffle-based board?..." | Read more » over 7 years ago
lperovich "Thanks for the suggestions everyone (@warren, @mathew, @liz, @DavidMack)! I've tried a number of things in the past few months and wanted to post a..." | Read more » over 7 years ago
lperovich "Thanks @DavidMack! I added some comparison summary data and plots to the post. " | Read more » almost 8 years ago
DavidMack "EPA Charles river buoy for comparison: " | Read more » almost 8 years ago
liz " This whole folder is fantastic - @eymund is a craftsman " | Read more » almost 8 years ago
liz " " | Read more » almost 8 years ago
liz "The Beer ball was in fact the original idea Summer 2012 -- do you have photos of Eymund's original prototype handy? I'll try to find them. It's fan..." | Read more » almost 8 years ago
warren "OMG I forgot about that post! One of my faves. Awesome, @mathew! " | Read more » almost 8 years ago
mathew "I know you're looking for a sphere, but I'd instead look for a hydrodynamic shape that can be pulled without a ton of actual "bobbing." on the thin..." | Read more » almost 8 years ago
warren "Hi, I think the enclosure could be a lot smaller, if you build on some of the other work folks have done on thermal fishing bob designs, for exampl..." | Read more » almost 8 years ago
DavidMack "first thing that comes to mind is a beer ball--do they even make those anymore? also look at "floating pool lights" Maybe you can get them wholes..." | Read more » almost 8 years ago
cfastie "These are compelling results. Would you conclude that: With these sensors, You would have to stay in one place for about 10 seconds to get a rea..." | Read more » almost 8 years ago
ajawitz "I've been slowly building a "buoyancy-driven underwater glider" robot, as an extension of the thermal fishing bob concept. It now has a dedicated ..." | Read more » almost 8 years ago
ajawitz "Now that this project is taking on a life of its own, I figured it was time to give it, its own research note at-" | Read more » almost 8 years ago
lperovich "Nice tests! A few comments: Good catch on the 3.3V/GND errors in the diagram. Here's the updated image: "The input code and the LED code need..." | Read more » almost 8 years ago
warren "Oh, great -- did you see some of my suggestions in ? ..." | Read more » almost 8 years ago
warren "Hi - I posted a link to a very cheap and tiny Arduino-compatible board called the Digispark, which could let you miniaturize everything - http://pu..." | Read more » almost 8 years ago
warren "Oops, digispark: " | Read more » almost 8 years ago
warren "Hi, just wanted to confirm that you're using multiple thermistors to get multiple depth measurements, and not to speed up your temperature readings..." | Read more » almost 8 years ago
warren "have them update in serial fashion Hi - just wanted to connect the dots here between @kh_machine, @neilhendrick, @kgrevera, and @lperovich - We d..." | Read more » almost 8 years ago
ajawitz "I might have a temporary workaround for the control issue... At least until we can incorporate some kind of autonomous navigation... According t..." | Read more » almost 8 years ago
ajawitz "UPDATE 6/29/15: I've managed to build most of the "buoyancy engine" with a large syringe, 3D printed parts, threaded drive bolts and metal "BBs"..." | Read more » almost 8 years ago