HemiPhysioData vs Chronographer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
HemiPhysioData
This app collects raw and processed sensor data from your Apple Watch, including accelerometer and gyroscope readings. It allows you to select activities, preferences, and then exports the data as a CSV file to your iPhone for analysis. Ideal for tracking movement and Range of Motion (ROM) measurements.
- Collects raw and processed sensor data
- User-friendly activity selection
- Exports data as CSV files
- Supports accelerometer and gyroscope
- Configurable sampling rate
- Haptic feedback for logging alerts
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HemiPhysioData serves as an Apple Watch app designed to gather both raw and processed data from the watch's built-in sensors, such as the accelerometer and gyroscope. Its user-friendly interface allows users to effortlessly select different activities and preferences. The collected sensor data, along with additional specified values, is then neatly stored in a CSV file. These CSV files can be easily transferred to the user's iPhone for further processing and analysis. The app is specifically tailored for individuals seeking to collect movement data or Range of Motion (ROM) measurements, with the added benefit of utilizing the data for analytics and machine learning. Users have the flexibility to choose the activity type, movement type, sampling rate (samples per second), and indicate which wrist they wear the watch on, as well as whether it's their dominant or non-dominant side. Some details on screenshots: UID: Predefined twenty users (U01-U20) Activity: Movements (upper limb), Walking, Running, Misc Move Type: It corresponds to the selected activity Interval-Hertz: Samples per second (up to 100 samples per second) Dominant Side: Enable it when watch is on wrist of dominant arm Right Wrist: Enable it when watch is on right wrist Haptic-Feedback: When enabled, the user can set the ‘Starts In’ time and the logging ‘Duration'. The user gets the alert when the logging starts (when the starts-in time finishes) and ends (when the duration finishes). Use this option to log activity related data only. It saves from data cleaning later. Logged Files: Shows all saved CSV files on watch. The user can select a file to send to the iPhone or delete from watch. The following sensor data of the Apple Watch (WatchOS) is saved in the CSV file: - Device Motion Processed Data: roll, pitch, yaw, rotation rate x, rotation rate y, rotation rate z, gravity x, gravity y, gravity z, user acceleration x, user acceleration y, user acceleration z, quaternion x, quaternion y, quaternion z, quaternion z. -Accelerometer Raw Data: Acceleration x, y, and z
Chronographer
This app helps you meticulously track the accuracy of your mechanical watches. It records time differences, calculates detailed performance metrics, and visualizes trends with charts and histograms. You can also manage your watch collection, log daily wear, and analyze positional variations.
- Track mechanical watch accuracy
- Calculate detailed performance metrics
- Visualize accuracy with charts and histograms
- Manage watch collection with notes and photos
- Log daily watch wear
- Analyze positional variation
- Export watch data
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Chronographer is for people who enjoy mechanical watches. It does two things: 1. Tracks your watches’ long-term accuracy 2. Records wrist time Chronographer can work with your whole watch collection. Give each watch a name and, optionally, a longer description. Select a picture from your Photos library and add additional notes, such as the watch’s specifications, purchase details, and service history. All information is stored in iCloud and automatically synchronized between your devices. To track a watch’s accuracy, periodically collect data points comparing its indicated time to the current correct time. Chronographer tracks offsets (the difference from the correct time) and daily rate (how many seconds it gains or loses per day). It uses this information to create graphs and histograms that help you visualize your watch’s performance over time. Chronographer also calculates the following metrics: • Average Offset • Max. Positive Offset • Max. Negative Offset • Last Offset • Net Gain/Loss • Best-Fit Rate • Average Rate • Fastest Rate • Slowest Rate • Last Rate • Rate Variance • Best-Fit Rate Drift You can log the watch (or watches) you wear each day. Chronographer’s wrist time tracking feature lets you see which watches you wear the most and how long it’s been since you’ve worn each one. You can use Chronographer to identify positional variation. When you record a data point, include the position (dial up, crown up, etc.) that the watch was stored in. Then, you can restrict the charts and metrics to specific positions and compare the results. Chronographer includes a large digital clock to help when you set your watches. For more information, including a detailed user’s guide, see https://www.rmfrance.net/chronographer
Screenshots
Verdict
The clearest difference is review sentiment: HemiPhysioData at 100% against Chronographer's 50%. HemiPhysioData also leads on iOS requirement (13.2 vs 18.6). Chronographer's advantage is update cadence (every 2 months vs every 18 months). On price, ads, in-app purchases and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
HemiPhysioData ships an update every 18 months, Chronographer every 2 months. The most recent releases landed on June 4, 2026 and August 9, 2026 respectively.
| Parameter | HemiPhysioData | Chronographer |
|---|---|---|
| Price | Free | Free |
| Rating | — | 3.0 (4 ratings) — better |
| Positive reviews | 100.0% of reviews — better | 50.0% of reviews |
| Number of ratings | — | 4 — better |
| Update frequency | Every 18 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPod, Apple Watch — better | iPhone, iPad |
| Requires iOS | 13.2 — better | 18.6 |
| Further details — not scored | ||
| Size | 2 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | Moez ur Rehman | Robert France |
Customer experience
HemiPhysioData
Chronographer
In-app purchases
HemiPhysioData
No in-app purchases
Chronographer
No in-app purchases
Questions
Is HemiPhysioData free?
Is Chronographer free?
Do HemiPhysioData or Chronographer have ads?
Which is updated more often, HemiPhysioData or Chronographer?
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