# Science exhibition projects with Arduino and ESP32: 8 ideas that teach something > Eight science exhibition projects run from USB: plant thirst meter, weather station, sound distance, tilt, light, water quality, sun tracker, reaction time. [HTML version](https://soldr.ai/blog/science-exhibition-projects-arduino-esp32) 8 November 2026 · Soldr **Short answer:** the best exhibition projects measure something real and show it live: soil moisture, air pressure, distance, tilt, light, water quality. Below are eight that run from a USB power bank, use parts that plug into a breadboard, and each come with a link that opens Soldr with the build described. Pick one, then explain the science behind the number on the screen. Judges and visitors remember a project that does something while they watch, and a student who can explain why it works. These ideas are built around one sensor each, so the science is clear. Each lists the sensor, what it teaches, and a ready prompt. All of them stay on low voltage, powered from USB. ## 1. Plant thirst meter A capacitive moisture probe in a pot and a small OLED that shows how dry the soil is, with a "water me" message below a threshold. **Teaches:** how water changes the soil's electrical properties, and why a capacitive probe lasts longer than bare metal. [Open this build on Soldr](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20plant%20thirst%20meter%20with%20an%20ESP32%2C%20a%20capacitive%20soil%20moisture%20sensor%20and%20a%200.96%20inch%20OLED%20that%20shows%20the%20moisture%20level%20and%20a%20water%20me%20message%20when%20the%20soil%20is%20dry) ## 2. Mini weather station A [BME280](https://soldr.ai/docs/components/bme280) sensor reading temperature, humidity and air pressure on an OLED. **Teaches:** how air pressure falls with height (carry it up the stairs and watch), and what relative humidity means. [Open this build on Soldr](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20mini%20weather%20station%20with%20an%20ESP32%2C%20a%20BME280%20sensor%20and%20a%200.96%20inch%20OLED%20that%20shows%20temperature%2C%20humidity%20and%20air%20pressure) ## 3. Speed of sound distance meter An [HC-SR04](https://soldr.ai/docs/components/hc-sr04) ultrasonic sensor showing distance in centimetres. **Teaches:** echoes and the speed of sound. Distance is half the round-trip time multiplied by the speed of sound, and the sensor's datasheet range is 2 cm to 4 m. [Open this build on Soldr](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20distance%20meter%20with%20an%20Arduino%20Uno%2C%20an%20HC-SR04%20ultrasonic%20sensor%20and%20a%2016x2%20I2C%20LCD%20that%20shows%20the%20distance%20in%20centimetres) ## 4. Gravity and tilt meter An [MPU6050](https://soldr.ai/docs/components/mpu6050) motion sensor showing the tilt angle as you rotate the board. **Teaches:** an accelerometer measures gravity, about 9.8 m/s² straight down, and the angle comes from how that splits between the axes. [Open this build on Soldr](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20tilt%20meter%20with%20an%20ESP32%2C%20an%20MPU6050%20motion%20sensor%20and%20a%200.96%20inch%20OLED%20that%20shows%20the%20tilt%20angle%20and%20a%20bubble%20level) ## 5. Light and distance experiment A [BH1750](https://soldr.ai/docs/components/bh1750-gy-30) light sensor reading lux as you move a torch closer and further. **Teaches:** light from a small source spreads out, so the reading drops quickly with distance. Record readings at several distances and plot them. [Open this build on Soldr](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20light%20meter%20with%20an%20ESP32%2C%20a%20BH1750%20light%20sensor%20and%20a%200.96%20inch%20OLED%20that%20shows%20the%20light%20level%20in%20lux%20and%20logs%20readings%20to%20the%20serial%20monitor) ## 6. Water quality comparison An analog [TDS sensor](https://soldr.ai/docs/components/tds-sensor) comparing tap water, filtered water and salt water in cups. **Teaches:** dissolved salts make water conduct electricity, and conductivity gives an estimate of total dissolved solids. Present it as a comparison between samples, not a drinking-water test. [Open this build on Soldr](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20water%20quality%20comparison%20with%20an%20ESP32%2C%20an%20analog%20TDS%20sensor%20and%20a%200.96%20inch%20OLED%20that%20shows%20a%20reading%20for%20each%20water%20sample) ## 7. Sun-following panel Two light sensors either side of a small card "panel" on an [SG90 servo](https://soldr.ai/docs/components/sg90), which turns towards the brighter side. **Teaches:** feedback control, the same idea a real solar tracker uses. Power the servo from its own 5 V supply with a common ground, as the servo maker advises. [Open this build on Soldr](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20sun%20following%20panel%20with%20an%20Arduino%20Uno%2C%20two%20LDR%20light%20sensors%20and%20an%20SG90%20servo%20that%20turns%20a%20small%20card%20towards%20the%20brighter%20side) ## 8. Reaction time tester An LED that lights after a random wait, a button, and an LCD showing your reaction time in milliseconds. **Teaches:** human reaction time, averages and variation. Collect results from visitors at the stall and show the spread. [Open this build on Soldr](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20reaction%20time%20tester%20with%20an%20Arduino%20Uno%2C%20an%20LED%2C%20a%20push%20button%20and%20a%2016x2%20I2C%20LCD%20that%20shows%20the%20reaction%20time%20in%20milliseconds%20and%20the%20best%20score) ## Keeping the stall safe - **Power from USB**, from a power bank or a laptop. None of these projects needs mains wiring, and none should use it. - **No battery charging at the stall.** If you use a lithium cell, charge it at home, supervised, never unattended. - **Keep water away from the board.** In the water and plant projects, only the probe goes in the water or soil; the board and wiring stay dry and to one side. - **Tape down loose wires**, so visitors' hands don't pull them out. ## How to present it - State the question ("Does air pressure change between the ground floor and the roof?"). - Show the live reading, and change something so visitors can see it respond. - Explain the sensor in a sentence or two, using the datasheet facts on its reference page. - Show your recorded results: a table or a simple graph. - Say what surprised you, and what you'd improve. Each link above opens a build with the parts, wiring and code, which you can change before you start. For more ideas aimed at students, see [AI-based electronics projects for students in India](https://soldr.ai/blog/ai-based-electronics-projects-for-students-india). If your board doesn't show up when you plug it in, see [CH340 and CP210x drivers](https://soldr.ai/blog/ch340-cp210x-driver-com-port). Parts on Compoden: [ESP32-DevKitC](https://compoden.com/products/esp32-devkitc-development-board-black-wifi-bluetooth-module), [Uno R3](https://compoden.com/products/uno-r3-ch340g-atmega328p-board-arduino-compatible), [capacitive soil moisture sensor](https://compoden.com/products/capacitive-soil-moisture-sensor-v20-corrosion-resistant-analog-probe), [BME280](https://compoden.com/products/bme280-sensor-module-temp-humidity-pressure-i2cspi), [HC-SR04](https://compoden.com/products/hc-sr04-ultrasonic-sensor-module-5v-distance-2cm-400cm), [BH1750](https://compoden.com/products/gy-30-bh1750fvi-light-intensity-sensor-module-for-arduinoesp), [TDS sensor](https://compoden.com/products/analog-tds-water-quality-meter-v10-sensor-for-arduino). Sign in and get 100 credits free.