DS1923 Hygrochron Temperature + Humidity Logger
The only iButton that logs relative humidity — 0–100 % RH alongside temperature, from one sealed can.
Temperature alone does not explain condensation, mould growth, corrosion or a delaminated tablet coating — humidity does, and the DS1923 is the only device in this family that measures it. Both channels are logged to the same 8 KB memory against one timestamp, so you never have to correlate two devices' clocks after the fact. Humidity resolves to 0.04 % RH at 12-bit, temperature to 0.0625 °C, and 64 bytes of on-chip calibration data let the software correct both channels. Chosen for pharmaceutical storage, museum and archive monitoring, electronics warehousing and any dispute where "it got damp" has to become a number.
The only one that measures humidity
This is not a better temperature logger — it is a different measurement. The other three tell you the temperature history; only the DS1923 also tells you the moisture history, on the same timestamp, from the same sealed can. If your damage claims involve condensation, mould, corrosion, caking or swollen packaging, temperature alone will never settle the argument and no amount of accuracy on the other models will help. Note the narrower −20 °C lower limit: for deep-frozen goods, use a DS1922L or DS1925 instead.
Key features
- Logs BOTH temperature and humidity in a single rugged iButton.
- Capacitive-polymer RH sensor: 0–100 %RH range, ±5 %RH accuracy, down to 0.04 %RH (12-bit) resolution.
- Temperature to 0.0625 °C (11-bit), better than ±0.5 °C after software correction.
- 8 KB log, 1 s–273 hr sampling, independent temperature and humidity alarms; two-level password protection.
- Hydrophobic filter shields the sensor from dust, droplets and condensation; NIST-traceable calibration.
Specifications
| Chip / compatibility | DS1923 · family code 41h · digital humidity + temperature |
|---|---|
| Memory | 8 KB data log = 8192 readings (8-bit) or 4096 (16-bit) + 512 B user SRAM + 64 B calibration memory |
| Operating temperature | −20 to +85 °C · 0.5 °C (8-bit) or 0.0625 °C (11-bit) · ±0.5 °C software-corrected (−10…+65 °C) |
| Options | Humidity 0–100 % RH · 0.6 % RH (8-bit) or 0.04 % RH (12-bit) resolution · both channels share one timestamp |
| Protocol | Sample rate 1 s to 273 h; delayed or alarm-triggered start; two-level password protection |
| Package | F5 stainless can with vapour-permeable seal — keep away from condensing water and solvents |
Inside the stainless can
A 0.25 mm solid stainless shell, a UV-stable polypropylene grommet isolating lid from base, and the die bonded inside. Lid = data contact, base = ground return.
Which logger should you order?
The four Thermochron / Hygrochron loggers side by side — specifications per the Analog Devices datasheets.
| DS1921G | DS1922L | DS1923 | DS1925 | |
|---|---|---|---|---|
| Measures | Temperature | Temperature | Temperature + humidity | Temperature |
| Range | −40 to +85 °C | −40 to +85 °C | −20 to +85 °C · 0–100 % RH | −40 to +85 °C |
| Accuracy | ±1 °C | ±0.5 °C | ±0.5 °C · ±5 % RH | ±0.5 °C |
| Best resolution | 0.5 °C | 0.0625 °C | 0.0625 °C · 0.04 % RH | 0.0625 °C |
| Log capacity | 2048 readings | 8192 readings (8 KB) | 8192 readings (8 KB) | 125,440 readings (122 KB) |
| Fastest sample rate | 1 min | 1 second | 1 second | 5 min |
| Histogram | Yes — 63 bins at 2 °C | — | — | — |
| Password protection | — | Two-level | Two-level | Two-level |
| Family code | 21h | 41h | 41h | 53h |
| Choose it when… | Volume cold-chain shipments, lowest cost per trip | Process validation, fast excursions, tight accuracy | Condensation, mould, corrosion — RH matters | Long ocean freight, year-long unattended missions |
Ordering information
| MOQ | 100 pcs |
|---|---|
| Lead time | 3–7 days for stock items, 10–15 days for OEM |
| Packing | Bulk ESD bags (100–200 pcs/bag, 2 bags/carton); blister or header cards for retail on request |
| Samples | Free samples for volume buyers — courier at cost |
| Payment | T/T bank transfer; other terms negotiable for repeat orders |
| Shipping | DHL / FedEx / UPS air express; sea or rail freight for pallet volumes |
| Customization | ROM ranges · housing colours · laser logo · private label |
Typical applications
Frequently asked questions
Is the DS1923 the only iButton that measures humidity?
Yes. Within the Thermochron/Hygrochron family the DS1923 is the only device with a humidity channel: 0–100 % RH, ±5 % RH accuracy, resolving to 0.6 % RH at 8-bit or 0.04 % RH at 12-bit. Temperature and humidity are written to the same 8 KB log under a single timestamp, so the two curves are already aligned when you read them out — no correlating clocks between two separate devices.
Can the DS1923 go into a freezer or get wet?
Its logging range starts at −20 °C, so for deep-frozen goods (−30 °C and below) choose a DS1922L or DS1925 instead. On moisture: the humidity sensor needs vapour to reach it, so the can is not sealed the way a plain temperature logger is — avoid condensing water, immersion, solvents and aggressive cleaning agents. Prolonged saturation above 90 % RH can also shift the reading until the sensor dries out.
Related products
DS1921G Thermochron Temperature Logger
The workhorse cold-chain logger: 2048 timestamped readings plus a built-in histogram, −40 to +85 °C.
DS1922L High-Resolution Temperature Logger
±0.5 °C accuracy and 0.0625 °C resolution, sampling as fast as once per second.
DS1925 High-Capacity Long-Mission Logger
125,440 timestamped readings — 15× the DS1922L, enough for a year-long mission at one point per 5 min.