Sensor that can pick up insect activity

Question

Hi Everyone,

This is my first post so I wasn't to sure where to put this, this looked like the best place.

Anyway, I have a project I want to do where I use an Arduino to detect insects, specifically whiteflies.

My problem is I'm not sure what type of sensor would be best suited for this application, since whiteflies are extremely small, I wanted to make use of a sonar setup to detect them when they swarm, but I am unsure if the resolution on a sonar module would be enough to detect them. This will happen in a closed greenhouse area so I'm not concerned about picking up unknowns and things.

I would like to be able to detect them at a range of about 100mm min and 500mm max, and they measure around 1-2mm each, at the bear minimum I would like to know that there are a couple flying around the location of the sensor, I do not need to know how many, and I would be happy if the sensor would be able to pick up only if there is a reasonable number.

So if anyone has any suggestions please speak up.

Thank you

jw0752 · Answer

Hi Josephus,

I had some time tonight so I bead boarded a simple circuit using an LED, a phototransistor,and an OP Amp. I hooked an oscilloscope up to the output of the Op Amp so I could monitor any signal that might be generated. I put a dark cover over the phototransistor with a darkened f-stop in front of it to give it tunnel vision. Opposite it on the circuit board I had a yellow LED also inside a cover with its output shining directly at the f-stop in front of the photo transistor. I used a piece of thread as the simulation of one of your insects. The thread was 0.26 mm wide. When I put the thread quickly through the space between the LED and the phototransistor it triggered the oscilloscope and recorded the signal.

Here is a picture of the circuit I used and the piece of string.

Here are pictures of the bread board and sensor setup. If you click on the pictures they will get bigger.

The last picture is a bitmap of what the oscilloscope saw when the thread was dragged past the gap between the LED and the Phototransistor. While this may or may not be the way you want to go it at least shows you a proof of concept.

John

jw0752 · Answer

Hi Josephus, Chances are that these insects have a wing beat frequency. If you can determine what that frequency is and select for it, then perhaps you could hear them with a sensitive microphone at a distance of 10 to 50 cm. I am not sure how you would tie this back to an Arduino but just detecting them is the first step. Another possibility would be to set up LEDs shining towards photo transistors. When a fly crosses the beam you would get a blip on the output of the photo transistor. You could collimate the LEDs so that each phototransistor could only see one LED. This would be similar to the sensor beam used on automatic garage door openers to sense objects under the door. This would be much easier to tie back to an Arduino as the blips in the output of the photo transistors would be detectable by an input pin if amplified. They actually use a technology similar to this in some smoke detectors. I will keep thinking and let you know if any other ideas come to mind. John

jw0752 · Answer

Hi Paul,

It came with a breadboard that I got from one of the Chinese Suppliers. It clips to the end of the bread board and has jumpers so you can select 5 volts or 3.3 volts for each of the upper and lower rails. I really like the way it works as I can pull power or ground from either side of the breadboard. It also has a push button power switch on the board. I power it with a 9 volt AC adapter that is designed for use on an Arduino. If you search E-Bay for Bread Boards it will probably pop up. I think the board and the power supply cost like $5.

John

D_Hersey · Answer

A bug zapper and a current sensor or microphone? [non-non-destructive testing]

gadget.iom · Answer

Thanks John

Just ordered one.

For anybody else who's interested, this is the one I've just purchased: http://www.ebay.co.uk/itm/MB102-Breadboard-Power-Supply-Module-Board-3-3-5V-For-Solderless-Bread-Board-/130907915844

jw0752 · Answer

Hi Sayed, It has been a couple of year since I posted this but I believe that I used an ISL28218 Op Amp a regular LED housed in a black rubber tube and a TEPT5600 TEPT5600 photo transistor also housed in a black rubber tube The black rubber tubes are important to act as collimators which keep outside light from contaminating the sensor This is similar to the technology that is used in smoke detectors to detect combustion particles in the air John

Sensor that can pick up insect activity

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