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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

Build log14 reports

  • nilsv1.0.01 months ago64.144h 40m

    USB enumeration failed until I added the 5.1k CC resistors. Check the errata.

    • swapped LDO for AP2112K
    • 3D-printed lid in PETG
  • kenjiv1.0.02 months ago42.026h 39m

    Worked first try. Reflowed with a hot plate at 190°C.

  • tomasv1.0.02 months ago43.664h 55m

    Printed the enclosure in PETG at 0.2mm, fits with no sanding.

  • luciav1.0.02 months ago45.084h 47m

    Substituted a cheaper mic; SNR is noticeably worse but usable.

  • wesv1.0.03 months ago43.103h 36m

    Printed the enclosure in PETG at 0.2mm, fits with no sanding.

  • ilyav1.0.03 months ago53.492h 42m

    Boot loop until I flashed with the 2.1 partition table. Docs could say this louder.

  • nilsv1.0.04 months ago64.495h 16m

    Running for three weeks continuously, no issues.

  • ilyav1.0.04 months ago57.585h 11m

    One cold joint on the ground pad — needed flux and a bigger tip.

  • ilyav1.0.04 months ago47.762h 35m

    Boot loop until I flashed with the 2.1 partition table. Docs could say this louder.

  • hexbytev1.4.04 months ago51.832h 53m

    Second build. Took half the time now that I know the order of assembly.

  • amarav1.0.05 months ago50.733h 40m

    Running for three weeks continuously, no issues.

    • swapped LDO for AP2112K
    • 3D-printed lid in PETG
  • sam-kv1.0.05 months ago56.755h 48m

    Running for three weeks continuously, no issues.

  • priyav1.4.05 months ago44.455h 30m

    Worked first try. Reflowed with a hot plate at 190°C.

  • priyav1.0.05 months ago48.556h 31m

    Worked first try. Reflowed with a hot plate at 190°C.