Theta vs Libre Light Sensor
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Theta
This application connects to specialized devices to measure and display galvanic skin response. It utilizes Wi-Fi and Bluetooth 4.0BLE to collect data on skin conductance, providing insights into physiological responses.
- Galvanic skin response measurement
- Wi-Fi connectivity
- Bluetooth 4.0BLE connection
- Skin conductance data display
- Physiological response tracking
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Application displays data from Theta-Meter devices (Wi-Fi and Bluetooth 4.0BLE connection) which measures human body galvanic skin response. Skin conductance, also known as galvanic skin response (GSR), electrodermal response (EDR), psychogalvanic reflex (PGR), skin conductance response (SCR) or skin conductance level (SCL), is a method of measuring the electrical conductance of the skin.
Libre Light Sensor
Measure ambient light levels in Lux using your iPhone's camera. Optimize sleep quality by understanding light exposure throughout the day and night.
- Measure light in Lux
- Utilizes iPhone camera
- Optimize sleep quality
- Track light exposure
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Measure light levels in any environment. Libre Light Sensor leverages your iPhone's camera to calculate luminosity as measured in Lux. This allows you to determine how much light exposure your eyes are receiving when you wake up, during the day, and before bed in order to optimize your sleep quality.
Screenshots
Verdict
The clearest difference is ratings volume: Libre Light Sensor at 113 against Theta's 1. Theta's advantage is review sentiment (100% vs 82%) and device support (4 vs 1). On price, rating, update cadence and ads 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.
Theta holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: Libre Light Sensor has 113 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 100% of Theta's written reviews are positive against 82% of Libre Light Sensor's.
Theta ships an update monthly, Libre Light Sensor every 5 weeks. The most recent releases landed on September 23, 2026 and September 22, 2026 respectively.
| Parameter | Theta | Libre Light Sensor |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | 4.8 (113 ratings) |
| Positive reviews | 100.0% of reviews — better | 82.4% of reviews |
| Number of ratings | 1 | 113 — better |
| Update frequency | Monthly — better | Every 5 weeks |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod, Mac — better | iPhone |
| Requires iOS | 11.0 — better | 16.0 |
| Further details — not scored | ||
| Size | 13 MB | 1 MB |
| Age rating | 12+ | 4+ |
| Developer | Mikhail Fedorov | John Harrington |
Customer experience
Theta
Libre Light Sensor
In-app purchases
Theta
No in-app purchases
Libre Light Sensor
No in-app purchases
Questions
Is Theta free?
Is Libre Light Sensor free?
Which has better reviews, Theta or Libre Light Sensor?
Do Theta or Libre Light Sensor have ads?
Which is updated more often, Theta or Libre Light Sensor?
Other comparisons
