# SD401

> SD401 (iPhone/iPad app by Owen Brown.)

- Source: https://appshunter.io/ios/app/sd401/id979499267 (this page in markdown: same URL + `.md`)
- Developer: [Owen Brown](https://appshunter.io/developer/979499266)
- Category: Utilities, Productivity
- Price: Free
- Age rating: 4+
- Requires: iOS 15.5 · 25 MB
- Languages: American English
- Released: 2015-04-07
- Data updated: 2026-05-18
- User reviews in markdown: https://appshunter.io/ios/app/sd401/id979499267/reviews.md

## What is SD401?

SD401 is a quality control system. The SD401 system consists of an iPhone with SD401 app and external SH7 Reader hardware (purchased separately). The SD401 app provides the GUI for displaying data. Data is received via Bluetooth communications from the SH7 Reader.

Displayed data is in numeric form with the addition of alarm “LEDS” for each data point. The number of displayed data points is configured via a setup screen, with password control. Also, the alarm LEDS are configured with limits set for each data point. A data value within limits will be shown with a “green” LED and value outside limits with a “red” LED.

Additional SH7 Reader readings such as temperature and battery voltage can be displayed in the app.


## Version history (last 5 releases)

### 2.5.8 — 2026-02-11

Channel red color indication when device disconnects.

### 2.5.6 — 2026-02-03

Fix to first channel absolutes.

### 2.5.5 — 2026-01-29

- Additional projects channels

### 2.5.3 — 2024-11-03

Minor bug fix

### 2.5.2 — 2024-02-06

Nothing New, Deployment target changed from 12 to 15.5

## Apps similar to SD401

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [M2go Sensor](https://appshunter.io/ios/app/m2go-sensor/id1166199314) | — | Free | Utilities |
| [JUMO Device](https://appshunter.io/ios/app/jumo-device/id1023671933) | — | Free | Utilities |
| [FreshLink](https://appshunter.io/ios/app/freshlink/id6480397498) | — | Free | Utilities |
| [IDSOT 2.0](https://appshunter.io/ios/app/idsot-20/id6720755789) | — | Free | Utilities |
| [Smart Tweezers LCR Bluetooth](https://appshunter.io/ios/app/smart-tweezers-lcr-bluetooth/id1124186849) | 5.0 (1) | Free | Utilities |
| [EzDx WeD-2](https://appshunter.io/ios/app/ezdx-wed-2/id6648756259) | — | Free | Utilities |

## More apps by Owen Brown

- [GD050](https://appshunter.io/ios/app/gd050/id1128663627)
- [Field Verifier](https://appshunter.io/ios/app/field-verifier/id1613136226)

All apps by Owen Brown: https://appshunter.io/developer/979499266

## Related topics

[sd401](https://appshunter.io/ios/topics/sd401)

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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 2026-05-18.*