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The Amazing Electric Fish Detector

Build an inexpensive probe that can monitor and record electric signals generated by weak electric fish remotely .

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Build an inexpensive probe that can monitor and record electric signals generated by weak electric fish remotely and without having to rely on manual labor. There has never been research done on them over a long period of time in the wild, due to the conditions of the environment and the limited time researchers have. The idea is to have an array of probes that record over a period of time and can notify researchers of activity.

Rivers in Africa are teeming with fish constantly outputting all sorts of electric signals, and these signals can be used to identify the species, each having its own unique signal.” There has not been a long-term study on weak electric fish due to the researchers having limited time and needing expensive, heavy equipment. Thus, this project is aimed to construct an electric signal detector to map the environment and the behavior of African electric fish, such as their feeding and mating behavior. The ideal probe would be anchored to the river and float, recording all night and day for a few weeks depending on its full power consumption. With wireless communication to the researcher’s camp base, the probe records electric signals at 116 kHz sampling rate of the fish in a particular area of an African river. The probe will turn itself on when a signal is detected, and off when there is no signal for 10 seconds. The gain can be controlled by the microcontroller itself if the signal makes the device clip and rail out. The included temperature gauge in the probe records when a signal is picked up, and signals are stored on an SD card. The data then can be analyzed to better the understanding of the environment and behavior of African electric fish or discover new species.

There hasn't been a long term study of these fish due to the extreme conditions and expensive equipment field researchers use. The majority of the time the field researchers use a stick with a wire attached to it and walk around in the river until they detect a fish.

This can be disastrous as the river is littered with slippery rocks and can go from being 1/2 meter deep to 5 meters deep in an instant. Making it very dangerous for field researchers to conduct research at night. After a fish has been detected they capture it and conduct tests at their base camp along the river.

About weak electric fish:

Weak electric fish produce an electric field around them with special organs called electrocytes. Anything that is conductive will make the field lines concentrate around that object, and if it is more resistive the field will warp around it. Also, the study of these electrocytes and how they are stacked is how the first battery was designed and created by Volta.

These fish use this electric field to map their environment, find food, other mates, and potential predators. They are active during the day but are very active at night.

There are different signals these fish produce depending on how their electrocytes are arranged.

The probe has to be able to recieve all frequencies these fish can produce.

_116kHz.ino

Fish Detector Code....so far. Increases sample rate and stores a signal when one is detected.

ino - 10.60 kB - 07/11/2016 at 13:56

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  • 1 × Arduino Zero Sample Signal at 100kHz
  • 1 × Audio Cable Used for probe
  • 1 × PVC Pipe Used for probe
  • 1 × TLC2272 Op-Amp
  • 1 × 0.47 uF ceramic capacitor Highpass filter

View all 12 components

  • Log #4

    Michael Haag07/11/2016 at 13:53 0 comments

    We are trying to add a Temp Gauge, GPS, without having our sample rate drop. Also to make the enclosure smaller and more bouyent.

  • Log #3

    Michael Haag07/08/2016 at 15:14 0 comments

    We have decided to leave out a sleep mode due to only having inbetween 10-16% of processing time before our sample rate drops below 100 kHz/second. The reason we chose 100 kHz/second is because these electric fish can produce signals up to 50us.

    We have implemented a waterproof enclosure that has the Arduino Zero, and the Amplification circuit.

    For the enclosure, we used a 4" PVC pipe with a cap on one side where the antenna is and a screw off cap on top to have easy access to the circuits. On one end of the PVC it is weighted to keep our probe upright in the water.

  • Log #2

    Michael Haag07/01/2016 at 17:29 0 comments

    We decided to switch to the Arduino Zero for our microcontroller. Due to Beaglebones high power consumption of 2.5 Watts, it would be unrealistic to try and power this device for weeks.

    We are still going to store the data on a SD card and have the Arduino Zero's built in RTC (real time clock) be used to timestamp each signal stored. The Arduino Zero will be in sleep mode and an analog device that can pick up signals will wake it from sleep mode and begin recording. This is to save power and have the device's battery last as long as possible.

  • Log #1

    Michael Haag07/01/2016 at 15:47 0 comments

    We started with the Beaglebone Black with a custom shield that used a MCP3008 ADC converter and a instrumentational op-amp to pick up the signals and then feed the signal through a op-amp to amplify it further . We decided to use a Beaglebone due to its high processing rate and its Linux OS. The shield included a speaker to notify the researchers if a fish is near, and to sample the signal at 100k Hz and store the data on a SD card.

    The probe was made out of a 3 1/2" long , 1/4" thick PVC pipe with a 3 wire audio cable. I used hot glue to hold everything in place, and to make sure the probe is waterproof.

    After a signal is received we store it on the Sd card in hexdecimal format with a header that included the date and time of recording.

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