reverse engineering and enhancing mosquito moth led suction trap

There was the hum of mosquito, a bite and an itch

i had to do something about it..

cheap USB mosquito trap (amazon search)

reasonable price and performance

some teardown photos

a series of LED's and motor powered by 5V / USB

bad resistor replaced by a wire

cant really tell why the dense bar barrier
maybe it helps to keep the insects when powered off

but its just adding pressure against the fan
and anyhow if its off then it doesn't catches flies

two common fan types are

static pressure - designed to push air

and high air flow - designed to move air

both have different properties such as

number of blades and different angle of attack

usually you would use a static pressure fan to push air against heat sink
in order to achieve it the blades need to be closer to each other
so that air couldn't flow back

and high air flow fan to ventilate open space
in order to achieve it the blades needs to be further away from each other
to catch and move more air

small dc motor probably cheaper to manufacture

power consumption suggesting

it can run from a small solar panel or batteries 

multiple LED's 

LED's wavelength - checked with spectrometer

some suction numbers using anemometer

half of the trap covered with a piece of fabric

increase the suction to a possible measurement point 

it actually seems to work better without the white bar barrier

which makes sense knowing how fans work

already possible to lower the BOM parts 

while enhance the trap efficiency by a 100%

and less pressure on the fan

meaning decreases in power consumption

final trap mod

after seeing the possibilities for improving the trap

i thought about building my own DIY version

using items i had in my home

its a 12V version powered by an ac dc transformer 

CPU fan + telescoping air guide

3W 400nm star heatsink LED

dc dc for driving the LED
or even better a drop down 2W resistor
to generate heat to further attract the mosquitoes

a piece of mosquito net 

plastic storage box - also good for defusing the light

and the round cover assists the air flow

couple of wooden stick and some hot glue

some suction numbers

further reading

first a note of caution:

Harmful effects (taken from wiki)

In humans, excessive exposure to UV radiation can result in acute and chronic harmful effects on the eye's dioptric system and retina. 

The risk is elevated at high altitudes and people living in high latitude areas where snow covers the ground right into early summer and sun positions even at zenith are low, 

are particularly at risk.[49] Skin, the circadian system, and the immune system can also be affected.[50]

The differential effects of various wavelengths of light on the human cornea and skin are sometimes called the "erythemal action spectrum".[51] 

The action spectrum shows that UVA does not cause immediate reaction, but rather UV begins to cause photokeratitis and skin redness 

(with lighter skinned individuals being more sensitive) at wavelengths starting near the beginning of the UVB band at 315 nm, and rapidly increasing to 300 nm. 

The skin and eyes are most sensitive to damage by UV at 265–275 nm, which is in the lower UVC band. At still shorter wavelengths of UV, damage continues to happen, 

but the overt effects are not as great with so little penetrating the atmosphere. The WHO-standard ultraviolet index is a widely publicized measurement of 

total strength of UV wavelengths that cause sunburn on human skin, by weighting UV exposure for action spectrum effects at a given time and location. 

This standard shows that most sunburn happens due to UV at wavelengths near the boundary of the UVA and UVB bands.

Aedes aegypti (Diptera: Culicidae) Vision: Spectral Sensitivityand Other Perceptual Parameters of the Female EyeLYNDA E. MUIR,12 MALCOLM J. THORNE,* AND BRIAN H. KAY

1J. Med. Entomol. 29(2): 278-281 (1992)

ABSTRACT From measurements of the mean ommatidial diameter (17.2 /xm) and mean interommatidial angle (6.2°) of the eye of female Ae. aegypti (L.), a minimum resolvableangle of 12.3° and an eye parameter of 1.6 /urn were calculated. The eye had relatively pooracuity but high overall sensitivity to light. Electroretinographs revealed spectral sensitivityranging from ultraviolet (323 nm) to orange-red (621 nm), with sensitivity peaks in theultraviolet (Amax323—345 nm) and green (Amnx523 nm) wavelengths. The retina is capable of some wavelength discrimination.

KEY WORDS Insecta, Aedes aegypti, vision, spectral sensitivity