# CO2 sensor — Display SCD-41 CO2 readings.

> Bluetooth sensor app for real-time CO2, temperature, and humidity readings. (iPhone/iPad app by Simon Loffler.)

- Source: https://appshunter.io/ios/app/co2-sensor/id1643286074 (this page in markdown: same URL + `.md`)
- Developer: [Simon Loffler](https://appshunter.io/developer/377815161)
- Category: Utilities, Health & Fitness
- Price: Free
- Rating: 2.70/5 from 3 App Store ratings
- Age rating: 4+
- Requires: iOS 15.6 · 0 MB
- Languages: American English
- Released: 2022-09-29
- Data updated: 2026-06-01
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/co2-sensor/id1643286074/reviews.md

## What is CO2 sensor?

Read CO2, temperature, and humidity from your Bluetooth Sensirion SCD-41 sensor in realtime. Save your readings with your current location and have it sync across your devices via iCloud. See previously saved readings with a map of the location that those readings were taken.

Works across iPhone, iPad, and macOS devices.

Open source code: https://github.com/sighmon/ios-ble-co2-sensor

## Key features

- Real-time CO2, temperature, and humidity readings
- Bluetooth sensor integration
- Save readings with location
- iCloud sync across devices
- Map view of saved readings
- Open source code available


## Frequently asked questions about CO2 sensor

### What devices does CO2 sensor work on?

CO2 sensor is compatible with Mac, iPhone, iPad, and iPod devices. It utilizes iCloud sync, making it convenient for users with multiple Apple products.

### How often is CO2 sensor updated?

The latest version of CO2 sensor is 1.3, last updated on September 29, 2025. While specific update frequency isn't detailed, the app has seen regular updates since its release in 2022.

### Is CO2 sensor suitable for children?

CO2 sensor has an age rating of 4+, indicating it is appropriate for young users. The app's functionality is straightforward and focuses on displaying sensor data.

### What is the user sentiment for CO2 sensor?

User sentiment for CO2 sensor appears mixed, with an average rating of 2.7 stars from 3 ratings. This suggests some users may have encountered issues or have specific feature requests.

### Does CO2 sensor have ads?

No, CO2 sensor does not contain advertisements. The app is free to download and use without any ad interruptions.

### Can I use CO2 sensor without a Bluetooth sensor?

No, CO2 sensor requires a Bluetooth Sensirion SCD-41 sensor to function. The app's primary purpose is to display readings from this specific hardware.

### What data can I save with CO2 sensor?

You can save CO2, temperature, and humidity readings along with your current location. This data can then be synced across your devices via iCloud for later review.

### Is the source code for CO2 sensor available?

Yes, the source code for CO2 sensor is publicly available on GitHub. This allows developers to inspect, modify, or contribute to the project.

## Version history (last 3 releases)

### 1.3 — 2025-09-29

Updated for iOS 26.

### 1.2 — 2023-07-21

We added the ability to export CO2 sensor readings to an InfluxDB database.

### 1.0 — 2022-10-01

No release notes.

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## More apps by Simon Loffler

- [Timelapse Helper](https://appshunter.io/ios/app/timelapse-helper/id417703416)
- [OS One](https://appshunter.io/ios/app/os-one/id6447306476)
- [Mearth](https://appshunter.io/ios/app/mearth/id6761681461)

All apps by Simon Loffler: https://appshunter.io/developer/377815161

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-01.*