# SentinelTDS vs Magnetic Detector

The clearest difference is price: SentinelTDS at Free against Magnetic Detector's $2.99. SentinelTDS also leads on in-app purchases (none vs 1) and update cadence (every 6 months vs every 60 months). Magnetic Detector's advantage is iOS requirement (12.1 vs 15.6). On ads and device support there is nothing between them.

SentinelTDS is free to download; Magnetic Detector costs $2.99 up front. Magnetic Detector sells 1 one-off in-app purchase. SentinelTDS asks for nothing beyond the download.

SentinelTDS ships an update every 6 months, Magnetic Detector every 60 months. Both last shipped on November 2, 2026.

## The numbers

| Metric | SentinelTDS | Magnetic Detector |
| --- | --- | --- |
| Price | **Free** | $2.99 |
| Rating | — | **[4.4 (186 ratings)](https://appshunter.io/ios/app/magnetic-detector/id1436465173/reviews)** |
| Number of ratings | — | **186** |
| Positive reviews | — | 76.7% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 6 months** | Every 60 months |
| Monetization | — | Free with in-app purchases |
| Size | 4 MB | 90 MB |
| Requires iOS | 15.6 | **12.1** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Técnicas de Soft, SA](https://appshunter.io/developer/1201704143) | [Jorge Gregorio Martin Bello](https://appshunter.io/developer/567988393) |

## What reviewers say

### SentinelTDS

[App page](https://appshunter.io/ios/app/sentineltds/id1201704144)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Magnetic Detector

[App page](https://appshunter.io/ios/app/magnetic-detector/id1436465173)

Detect hidden metal objects like studs and fasteners within walls using your device's magnetic sensor. The app measures magnetic field strength, providing visual and auditory feedback as you scan.

**Highlights:** Detects wood studs and metal fasteners, Uses device's magnetometer sensor, Visual needle and active beep feedback, Measures magnetic field in μT, Identifies nearby metal objects

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock all Features | $2.99 | one-time |

**What reviewers like**

- ✅ Effectively detects metal and magnetic fields
- 👍 Simple and user-friendly interface
- 🎯 Works well for finding studs in walls
- 💰 Free or affordable pricing
- 🔧 Useful for home renovation and DIY projects

**What reviewers complain about**

- 🐛 Crashes and freezes frequently
- ⏱️ Limited free trial time
- 📢 Intrusive pop-up advertisements
- ❌ Inconsistent performance across devices
- 🚫 Does not work through drywall effectively

**Reported bugs**

- App crashes before detection can occur
- Freezes after first use, requires phone reboot
- Fails to detect studs through drywall
- Performance issues on iPad
- Inconsistent detection results on certain devices

**Requested features**

- Longer free trial duration
- Directional indicator for magnetic sources
- Clearer sensor location guidance
- Benchmark or calibration tool for verification
- Multi-language support for customer service


## Frequently asked questions

### Is SentinelTDS free?

SentinelTDS is free to download, with no in-app purchases.

### Is Magnetic Detector free?

Magnetic Detector costs $2.99, and also offers in-app purchases.

### Do SentinelTDS or Magnetic Detector have ads?

Neither SentinelTDS nor Magnetic Detector shows ads.

### Which is updated more often, SentinelTDS or Magnetic Detector?

SentinelTDS ships an update every 6 months, and Magnetic Detector every 60 months. Most recently, SentinelTDS was updated on November 2, 2026 and Magnetic Detector on November 2, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*