Three lock types and when to pick each
You choose one when you first open Alert24, and you can switch later in Settings under Unlock Settings.
Passcode (PIN)
Four digits. Fastest to type with one thumb while a siren is ringing. Add a hint and a random keypad in Unlock Settings.
Pattern
Draw a line through at least four dots on a 3 by 3 grid. Easy to remember as a shape. You can hide the line while you draw it.
Knock code
Tap a sequence of four to eight knocks on four screen quadrants. Nothing shows on screen, so there is little for a bystander to watch.
How to set or change your lock
- 1
Pick a lock type
On first run, after the permissions screen, the Select Lock Type sheet offers Passcode, Pattern or Knock Code. Later, open Settings, then Unlock Settings, and tap the change lock option.
- 2
Enter it twice
Create the PIN, pattern or knock code, then repeat it on the Verify step. If the two do not match you are sent back to start again.
- 3
Add a recovery method
In Settings under Security Settings, save a security question and answer and a recovery e-mail. Do this now, not after you forget the code.
- 4
Turn on fingerprint
In Settings under Security, open Biometric Locks and switch on Fingerprint. An extra switch makes the fingerprint prompt appear automatically when the lock screen opens.
Random keyboard beats shoulder-surfers
A person standing behind you in a queue can learn a PIN by watching where your thumb lands. With Random Keyboard on, Alert24 shuffles the digits on the keypad every time the lock screen opens. Your thumb goes somewhere different each time, and the finger smudges on the glass tell nobody anything.
Pattern users can switch off the visible line so the shape is not drawn on screen, and can turn the touch vibration off. Knock-code users can hide the knock positions in the same way.
Fingerprint unlock
When Fingerprint is switched on in Biometric Locks, a fingerprint icon appears on the Alert24 lock screen and on the alarm screen. Touch the sensor and the app opens or the siren stops. It uses the fingerprints already enrolled on your phone.
Your PIN, pattern or knock code still exists underneath and always works, so you are never locked out because of a wet finger.
The alarm stops only with the same secret
When any alarm fires, a full-screen lock appears on top of everything, even the phone's lock screen, asking for the same secret. There is no cancel button, and the volume keys cannot take the siren below 60% of maximum. The siren rings for up to 5 minutes; the lock screen stays until the secret is entered.
That is why the app lock matters more than it looks. It is the single control that decides whether the Don't Touch My Phone alarm keeps ringing or goes quiet.
Wrong attempts trigger an intruder selfie
Every wrong entry on the app lock screen or the alarm screen is counted. When the count reaches the Pin Attempts limit you chose in Intruders Pictures (1, 2 or 3), the front camera takes a silent photo. It is saved in the gallery under App Intruders, or under the alarm type if it happened on the alarm screen.
So even if someone guesses wrong and gives up, you get to see who tried. Learn how photos are stored on the intruder selfie page.
Forgot your code? Three ways back in
Tap the menu on the lock screen and choose Forgot password. The option appears only when you have set up at least one recovery method.
Security question
Answer the question you saved. The answer must match exactly, including capital letters.
Recovery e-mail
Sign in with the Google account whose address matches your recovery e-mail. Needs an internet connection.
Fingerprint
If you allowed fingerprint to reset the code in Security Settings, your fingerprint lets you set a new one.
App lock: questions
Does Alert24 lock my other apps too?
No. This lock protects Alert24 itself and its alarms. If you want to lock WhatsApp, photos or banking apps, use a dedicated app locker such as GTS Infosoft's App Lock.
What is a knock code?
A sequence of four to eight taps on the four quarters of the screen. Nothing is drawn or typed, so it is hard to copy by watching.
Can I use my fingerprint to stop the alarm?
Yes. Switch on Fingerprint in Biometric Locks and a fingerprint icon appears on the alarm screen next to the PIN, pattern or knock pad.
What happens if I forget my PIN?
Use Forgot password on the lock screen and answer your security question, sign in with the Google account of your recovery e-mail, or use your fingerprint if you allowed it. Set these up in Security Settings before you need them.
Is the app lock free?
Yes. PIN, pattern, knock code, fingerprint and recovery are all in the free version. See the FAQ for what Premium adds.
Set your secret, then arm your first alarm
Install Alert24, choose a PIN, pattern or knock code, and nobody else can silence your phone.