Edge Ruler vs Link Alarm

Edge Ruler turns iPhone and iPad into a ruler that measures from the device corner. Hold the corner against an object, read length and width. No camera trick, no guessing: the app knows, for every device, the distance from the housing edge to the first pixel and draws the scale to the millimeter. Two corner rulers in opposite corners, two measuring lines with handles that lock when released, values in cm, inches with fractions or 寸. With Calibrate you place a bank card or coin on a real-size template and see at once whether everything lines up; bezel values can be adjusted in tenths of a millimeter. Five school worlds as outfits: grid paper and clear ruler like a German pencil case, yellow wooden ruler on wide-ruled paper like in the US, 田字格 with a tinted student ruler like in China, Seyès notebook with a “double décimètre” like in France, “cuadrícula” with a “regla” like in Spain. Paper, ruler, line color and unit combine freely. The basic ruler is free. Everything else can be tried for 14 days and then unlocked once: your region's outfit with second scale, rotating numbers, all four zero corners, movable zero, measurement table and inclinometer, or all five school worlds at once. Accurate to about 0.3 mm on calibrated models; not a certified measuring instrument. No data collected, no account, no internet.

This app connects two iPhones via Bluetooth and monitors their communication status. When you tap “Start Communication” on one iPhone, it starts Bluetooth communication with the other iPhone. If the Bluetooth connection is lost, an alarm notifies you and the app attempts to reconnect. If the connection is restored, the alarm stops and monitoring resumes. After the app has been running in the background for a long time, the connection may not be restored. For example, the app can be used to monitor two iPhones that you want to keep nearby, or to notify you when your child’s iPhone moves away. Main Features 1-to-1 Bluetooth communication between two iPhones Communication status monitoring Alarm when the Bluetooth connection is lost Reconnection after a connection loss Monitoring resumes after reconnection Communication monitoring while the iPhone is locked Japanese and English support Dark Mode support Note: This app detects Bluetooth disconnection and sounds an alarm.