# Arduino ADS1115 pH Sensor Interface ## Description Arduino-compatible pH probe interface using a high-impedance analog buffer and ADS1115 16-bit I2C ADC for improved pH measurement sensitivity. ## Project Details - **Owner:** sudaraka - **Created:** 5/20/2026 - **Last Updated:** 5/21/2026 - **Visibility:** Public ## Key Components ### J1 — [0731000105](https://www.flux.ai/adrian95/0731000105~u8d.md) - Manufacturer Part Number: 0731000105 - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.molex.com/content/dam/molex/molex-dot-com/products/automated/en-us/salesdrawingpdf/731/73100/731000105_sd.pdf?inline - Part Type: Connector - Manufacturer Name: Molex - Role: Sensing (Shunt) - Role Details: BNC connector for pH probe; center goes to high-impedance buffer and shield is biased to VBIAS rather than ground. **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J2 — [Pin Header 01x08 2.54mm Vertical](https://www.flux.ai/vasyl/pin-header-01x08-254mm-vertical~95x.md) - Part Type: Connector - Role: Sensing (Shunt) - Role Details: Header exposes VCC, GND, SDA, SCL, ALERT, ADDR, AIN2, and AIN3 for Arduino and extra sensors. **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] - 5 [pin 5] - 6 [pin 6] - 7 [pin 7] - 8 [pin 8] ### J3 — [Pin Header 01x03 2.54mm Vertical](https://www.flux.ai/adrian95/pin-header-01x03-254mm-vertical~cp4.md) - Part Type: Connector - Role: Sensing (Shunt) - Role Details: Through-hole connector for external waterproof DS18B20 temperature probe: pin 1 VCC/red, pin 2 DQ/yellow or white, pin 3 GND/black. - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] ### J4 — [Pin Header 01x02 2.54mm Vertical](https://www.flux.ai/jharwinbarrozo/generic-pin-header-01x02-2p54mm-vertical~4uy.md) - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Role Details: Through-hole Arduino digital GPIO header for DS18B20 1-Wire data; pin 1 DS18B20_DATA to Arduino D2/D3, pin 2 GND reference. - Role: Sensing (Shunt) **Pins:** - P1 [pin 1] - P2 [pin 2] ### U2 — [MCP6002-I/P](https://www.flux.ai/adrian95/mcp6002-ip~t3o.md) - Role: Amplification - License: https://creativecommons.org/licenses/by/4.0/ - Package or Case Code: DIP781W56P254L950H533Q8N - Manufacturer Part Number: MCP6002-I/P - Manufacturer Name: Microchip - Datasheet URL: https://ww1.microchip.com/downloads/en/DeviceDoc/MCP6001-1R-1U-2-4-1-MHz-Low-Power-Op-Amp-DS20001733L.pdf - Part Type: Operational Amplifier (OP-AMP) - Role Details: Through-hole DIP-8 dual CMOS rail-to-rail op amp: channel A buffers high-impedance pH probe center, channel B buffers the 2.5V probe reference/bias. **Pins:** - VDD [pin 8] - VINA- [pin 2] - VINA+ [pin 3] - VINB- [pin 6] - VINB+ [pin 5] - VOUTA [pin 1] - VOUTB [pin 7] - VSS [pin 4] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/sudaraka/arduino-ads1115-ph-sensor-interface~qs](https://www.flux.ai/sudaraka/arduino-ads1115-ph-sensor-interface~qs).* --- *Generated from [https://www.flux.ai/sudaraka/arduino-ads1115-ph-sensor-interface~qs](https://www.flux.ai/sudaraka/arduino-ads1115-ph-sensor-interface~qs)*