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
liz "This is a great question about bulk ordering. @mathew can you comment on this? " | Read more » almost 8 years ago
ajawitz "I just can't resist the temptation to build one myself! Even though the DIY version is probably useless in an ocean environment, it just looks so ..." | Read more » almost 8 years ago
ajawitz "Dan's response in the accompanying thread to this note in the discussion forum gave me an idea about retrieving the Glider in an ocean/large lake e..." | Read more » almost 8 years ago
ajawitz "i wonder if it really would make sense then to base the navigation controls off of a flight controller IMU like the one I've been (very slowly) dev..." | Read more » almost 8 years ago
danbeavers "Probably just pressure would be sufficient. I am not certain but there is probably a constant relationship between pressure change rate and speed/..." | Read more » almost 8 years ago
mathew "If flow/water speed and pressure/descent was being measured too then those measurements could be used to generate approximate locations between GPS..." | Read more » almost 8 years ago
danbeavers "I reviewed the design and there is no port and starboard control. That could be accomplished by changing the center of gravity to the left or righ..." | Read more » almost 8 years ago
ajawitz "In that case, perhaps a better question would be about using the sensor pod as a platform for RIFFLE or other Open Water tools? The only problem w..." | Read more » almost 8 years ago
danbeavers "I believe it would be better to just store the data and use dead reckoning between fixes. That assumes you get GPS on each surfacing. " | Read more » almost 8 years ago
neilhendrick "The thermister in use has a Thermal time constant <= 15 seconds, which is fine for some applications. However, to get a faster measurement, a di..." | Read more » almost 8 years ago
warren "Another approach could be to increase the transfer of heat by using a high surface area like the heat dissipating fins on a computer's CPU: You ..." | Read more » almost 8 years ago
cfastie "In a sense these sensors all have zero lag. As soon as the the materials that make up the sensor reach ambient temperature, the sensor will tell yo..." | Read more » almost 8 years ago
neilhendrick "Warren, Agreed. The thermister changes temperature when it is in your mouth, or submerged in water, faster than in air, because water is a better t..." | Read more » almost 8 years ago
warren "Hi - I think the sensing speed is affected by both: how well the thermistor is in contace with the water how much thermally conductive material i..." | Read more » almost 8 years ago
kgrevera "I will be attending! " | Read more » almost 8 years ago
neilhendrick "I will be attending! " | Read more » about 8 years ago
kgrevera "I will be attending! " | Read more » about 8 years ago
kanarinka "I got the email notification @warren. So super awesome to see the progress on this " | Read more » almost 9 years ago
donblair "Yay! @mathew: Great! And we already have a pretty nice relevant smt board design -- coin cell powered, with an RGB led and a piezo buzzer: http..." | Read more » almost 9 years ago
warren "@dorncox and I "riffed" on this idea today in Somerville... can we call it the Riffle Cricket, maybe, referencing that cricket chirps encode the ai..." | Read more » almost 9 years ago
mathew "I've been offline for the past four days or I would have been all "THIS! THIS!" immediately. because this is awesome! soooooooooo cool. We should..." | Read more » almost 9 years ago
amysoyka "Are you using a spark labs kit? " | Read more » almost 9 years ago
warren "@kanarinka and I chatted about this idea also at PDF, including found an audio version you could leave a voicemail with at the server to submit dat..." | Read more » almost 9 years ago
warren "Wow, very cool. Does the Arduino monitor it via a light sensor? I also want to test the new callouts feature: @mathew, did you get a notification ..." | Read more » almost 9 years ago