CampusGuard911 vs pi!
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
CampusGuard911
This safety app provides a direct panic button for university faculty and staff during emergencies. It alerts local law enforcement and campus personnel, displaying the location of the incident. The app also notifies nearby protected locations.
- Mobile panic button
- Alerts law enforcement
- Campus-wide alerts
- Location mapping
- Notifies nearby locations
- AT&T FirstNet listed
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CampusGuard911 is a mobile panic button app for university and college faculty and staff. In the event of an active campus shooting emergency, a faculty or staff member presses the main CampusGuard911 panic button. As the app is dialing 911, an alert is immediately sent to the smartphones of all federal, state and local, ON and OFF duty, law enforcement officers who are in close proximity to the school and who belong to the Hero911 Network. Additionally, an intra-campus alert is simultaneously sent to the smartphones of all faculty and staff and a mapped location of the initial alert is displayed (mapping depends on cell coverage). CampusGuard911 also alerts all other protected locations within a 5 mile radius of the initial alert. CampusGuard911 is also listed in the AT&T FirsNet App Catalog as an emergency app for first responders. Please be aware that continued use of GPS running in the background can dramatically decrease battery life.
pi!
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How many digits of π can you memorize? π Memorizer helps you learn and recall the digits of pi using a simple, focused approach: see the digits, hide them, type them back. No gimmicks — just effective memorization. LEARN • Study digits in customizable chunks of 5, 10, or 20 • See the digits, then hide and input them from memory • Pick up right where you left off — progress saves automatically • Browse all 10,000 digits with your learned positions highlighted • Tap any group to jump to that position and start practicing TEST • Type digits of π from memory as fast as you can • Timer starts on your first tap — no pressure until you're ready • See your entered digits organized in clean, readable groups • Wrong digit? Game over. See exactly where you went wrong and what the correct digit was • Beat your personal record and track your improvement STATS • Personal best record, learning progress, current streak • Average speed (digits per second), total sessions, and practice time • Full session history to review past attempts APPLE WATCH • Quick-test on the go with a compact numpad • Best record syncs with your iPhone via WatchConnectivity DESIGNED FOR APPLE • Liquid Glass design language — beautiful on iOS 26, iPadOS, and macOS • Apple Pencil Scribble support on iPad — write digits by hand • iCloud sync keeps your progress across all your devices • Haptic feedback on every tap for a satisfying input experience Whether you're a math enthusiast, a memory athlete, or just curious how far you can go — π Memorizer is your companion for the journey from 3.14 to 3.14159265358979323846…
Screenshots
Verdict
The clearest difference is iOS requirement: CampusGuard911 at 12.0 against pi!'s 26.0. On price, ads, in-app purchases and device support 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.
| Parameter | CampusGuard911 | pi! |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (4 ratings) — better | — |
| Number of ratings | 4 — better | — |
| Update frequency | Every 6 months | — |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Apple Watch |
| Requires iOS | 12.0 — better | 26.0 |
| Further details — not scored | ||
| Size | 58 MB | 4 MB |
| Age rating | 4+ | 4+ |
| Developer | Guard911, LLC | Sijun Yang |
In-app purchases
CampusGuard911
No in-app purchases
pi!
No in-app purchases









