Smart Mosquito Trap with CO2 and UV Attraction using ESP32

Mosquitoes find people largely by sensing exhaled carbon dioxide, which is why CO2-baited traps outperform simple UV zappers — but commercial CO2 traps are expensive imports. This project builds an affordable smart version from student parts: a drip-fed baking-soda and vinegar chamber generates a steady CO2 plume, a violet UV LED ring adds the visual lure, and a low-noise 12 V fan creates the suction that pulls approaching mosquitoes into a mesh catch chamber they cannot escape. An IR beam-break sensor across the intake counts each capture, and the ESP32 logs hourly counts to flash memory, shown live on an OLED with a daily total. An LDR enables the trap automatically at dusk and parks it at dawn, and a bait-low estimate reminds the user to refill the chamber. It is a complete embedded system — chemistry, airflow, sensing and logging — in one demonstrator.

1. At dusk the LDR crosses its threshold; the ESP32 wakes the trap, starts the fan and powers the UV ring.
2. The drip valve meters vinegar into the baking-soda chamber at a set rate, releasing a continuous CO2 plume from the outlet tube.
3. Mosquitoes following the CO2 gradient reach the intake, where the UV ring and fan airflow pull them into the mesh catch chamber.
4. Each insect crossing the intake breaks the IR beam; firmware debounces the signal and increments the capture count.
5. Counts accumulate per hour in flash memory; the OLED shows live count, nightly total and system status.
6. At dawn the LDR parks the system — fan and UV off, drip valve closed — and the bait estimator updates remaining charge.

Tech stack:

• ESP32 dev board
• 12 V DC fan · 395 nm UV LED strip
• IR beam-break sensor module
• LDR light sensor · 0.96 inch OLED (I2C)
• Baking-soda/vinegar CO2 chamber + drip valve
• Arduino IDE · C/C++ firmware

• [CO2 bait generation] Drip-fed baking-soda + vinegar reaction chamber produces a steady CO2 plume mimicking human breath — the primary long-range mosquito attractant.
• [UV lure ring] 395 nm UV LED strip around the intake adds the short-range visual cue that draws mosquitoes into the suction zone.
• [Suction capture] 12 V DC fan creates intake airflow into a mesh catch chamber; captured insects cannot fly back out against the airflow.
• [IR catch counter] Beam-break sensor across the intake throat counts each capture; the ESP32 debounces and logs hourly totals to flash.
• [Dusk-to-dawn automation] LDR light sensing runs the trap only when ambient light falls below threshold — bait and battery last through the nights that matter.
• [OLED dashboard] Live catch count, tonight's total, fan status and bait-level estimate on a 0.96-inch display.
• [Bait refill reminder] Firmware estimates CO2 charge depletion from runtime and flags refill on the display before the plume fades.

• Working smart mosquito trap prototype (trap chamber, fan, UV ring, CO2 generator, ESP32, sensors)
• Complete firmware source with counter, automation and logging
• Assembly diagram and airflow path documentation
• Bait mixing and drip-rate setup procedure
• Project report PDF (background, mosquito behavior basis, system design, testing)
• PPT presentation for final review
• Viva Q&A preparation document (IR sensing, LDR, debouncing, embedded logging)

• Capture effectiveness is placement- and species-dependent; no catch-rate figure is claimed — the report provides a buyer-run field-test procedure (count vs. a control location over 7 nights) instead of invented results.
• The CO2 charge lasts roughly one night per fill (expected); it is a consumable the user refills, not a fit-and-forget device.
• UV LEDs attract some non-target night insects too; the catch chamber is non-selective by design.
• Indoor bedroom use is discouraged — the trap is designed for verandas, courtyards and outdoor seating areas.
• The vinegar/baking-soda reaction is mild but the chamber must stay upright and away from children and pets.