Alarm Clock For Heavy Sleepers

The math problem appears on the screen at 6 AM

The phone is ringing loudly. You reach for it, half-asleep, and see a math equation: 14 + 27 = ?. Your brain is foggy. Your fingers are clumsy. But the alarm will not stop until you type the correct answer. There is no snooze button to tap. No dismiss button to hit. Just a math problem that forces your brain to wake up. This is the core experience of Alarm Clock For Heavy Sleepers, also known as ReAlarm. The app is built for people who struggle to wake up — the ones who sleep through multiple alarms, the ones who hit snooze without even remembering it. The app offers three main challenges: math problems, shaking the phone, and scanning a QR code. Each challenge is designed to force you out of bed and into a waking state before the alarm stops.

The math challenge has four difficulty levels. Easy includes single-digit addition. Medium adds subtraction. Hard introduces multiplication and division. Expert mixes all operations with larger numbers. You can also set how many problems you must solve — one, three, or five. The QR code challenge requires you to scan a specific code. You print the code and place it in another room. To stop the alarm, you have to get out of bed, walk to the code, and scan it. The shake challenge forces you to shake the phone a set number of times. These challenges are not gimmicks. They are scientifically designed to break the sleep inertia that keeps heavy sleepers in bed. The app also includes a "wake-up check" feature that ensures you are actually awake after the alarm stops.

How the interval alarm system works

The interval alarm system is the app's most powerful feature. You can set alarms to repeat at custom intervals — every 30 minutes, every 2 hours, every 5 days, or any other pattern. This is ideal for shift workers, people with irregular schedules, and anyone who needs reminders throughout the day. The app supports daily, weekly, monthly, and custom repeat patterns. It also includes a smart pause and resume feature. You can suspend recurring alarms during quiet hours or vacation mode. The app's scheduling engine is flexible enough to handle complex work rotations. It automatically skips holidays and supports make-up workdays. This is a significant advantage over standard alarm clocks that only support weekly patterns.

The interval alarms also integrate with the challenge system. You can attach a math, QR, or shake challenge to any interval alarm. This means you cannot simply dismiss the alarm without completing the challenge. For heavy sleepers, this is critical. The cognitive and physical effort required to complete the challenge ensures that you are fully awake before the alarm stops. The app also includes a "gradual volume increase" feature. The alarm starts softly and grows louder over time. This prevents the jarring shock of a sudden loud alarm. The sunrise simulation feature gradually brightens the screen, mimicking natural light. This helps regulate your circadian rhythm and makes waking up feel more natural.

What the version history and changelog reveal

The app has been updated regularly since its release in June 2025. The latest version is 3.9.3, released in June 2026. The changelog for version 3.9.3 includes several significant additions. The ISO week filter allows users to set alarms based on week numbers, which is ideal for shift workers with rotating schedules. The custom volume setting lets users fine-tune the alarm volume to their preference. The advanced snooze feature includes a maximum snooze limit and new notifications. The sunrise light feature uses the phone's screen to illuminate the room in the morning. The new multiple challenges include "find item" and "walk to close," which require physical movement to dismiss the alarm. The wake-up check feature ensures users are actually awake after the alarm stops. The secondary sounds feature adds an extra layer of audio to ensure the alarm is not missed.

The version history shows a pattern of steady improvement. Earlier versions focused on core functionality: interval alarms, math challenges, and basic statistics. Later versions added QR code scanning, weather integration, and voice announcements. The most recent updates have focused on advanced scheduling features and additional wake-up challenges. The developer, Feirox, is based in India and has been active in app development for over a decade. The app is available in 49 languages, supporting over 60 global regions. The app uses a split APK system, which keeps the base install size small and downloads only the language pack you need. The app is 100% offline and does not require registration. This is a strong privacy feature, especially compared to cloud-based alarm apps that store data on remote servers.

Performance, ads, and what actually breaks

The app performs well for most users. The interface is responsive and the challenges work reliably. However, there are some issues. The app contains ads, despite the description claiming "very few ads." Users have reported that ads appear frequently, interrupting the experience. The app is free, but the ads can be frustrating. The in-app purchases remove ads, but the pricing is not clearly stated. The app has a relatively small user base — around 7,000 installs — which means the community is limited. Some users have reported that the math challenges are too easy or too hard, depending on the difficulty setting. The app allows customization, but some users may not find the right balance. The iOS version has had issues with vibrating only while sending text messages, though the developer has fixed this.

Bugs are rare but not non-existent. Some users have reported that the app occasionally fails to trigger the alarm. This is a critical failure for an alarm app. The developer has addressed this with the Smart Permission Manager, which guides users through granting the necessary permissions for reliable alarms. The app requires permissions like SET_ALARM_CLOCK, WAKE_LOCK, and SCHEDULE_EXACT_ALARM. These are standard for alarm apps but can be blocked by Android's battery optimization. The app's documentation includes detailed instructions for configuring these permissions. The app also includes an auto-stop duration setting, which silences the alarm after a set time. This prevents the alarm from ringing indefinitely if you are unable to complete the challenge. The app's privacy policy states that no personal data is collected or shared with third parties. Data is encrypted in transit. This is a positive for privacy-conscious users.

Camera permissions and QR code scanning

The QR code challenge requires camera access. The app only uses the camera when the QR challenge is enabled. The app does not record or store any images. The QR code is generated uniquely within the app, ensuring that you cannot bypass the alarm with generic barcodes. You can save the QR code to your gallery and print it. The app also supports voice commands through Gemini AI integration. You can set alarms using voice commands like "Set a QR code challenge alarm for 7:30 AM." The app's multi-language support means you can use it in 49 languages. The app is available on both Android and iOS, though the iOS version is called "reAlarm-mobile clock" and has slightly different features. The app's permission requests are minimal. It does not request location, contacts, or microphone access unless you enable voice features. The app is designed to be lightweight and efficient. It runs in the background with minimal battery drain.