hydra/ph-probe
18-bit pH and temperature logger with a proper guard ring, USB-C, and a two-year coin-cell sleep current of 4µA.
v1.4.0rp20404-layer · 30×74 mm$42.80 BOM3h buildCERN-OHL-P-2.0updated 15 days ago
| Ref | Part | Qty | Unit | Ext | Source |
|---|---|---|---|---|---|
| U1 | RP2040 Raspberry Pi · Dual M0+ microcontroller | 1 | $0.80 | $0.80 | |
| U2 | MCP3421A0T-E/CH Microchip · 18-bit delta-sigma ADC with PGA | 1 | $3.60 | $3.60 | |
| U3 | INA333AIDGKR TI · Micro-power instrumentation amplifier | 1 | $4.15 | $4.15 | |
| J1 | BNC-50 Amphenol · BNC jack for the pH electrode | 1 | $2.40 | $2.40 | |
| R1-R4 | RT0402BRD071ML Yageo · 1MΩ 0.1% thin film | 4 | $0.18 | $0.72 | |
| PCB | JLC04161H-7628 JLCPCB · 4-layer 30×74mm ENIG, blue mask | 1 | $3.20 | $3.20 | |
| One complete build | $14.87 | ||||