Smart helmet is a protective cap. It will be designed especially for factories that contain large group of workers and work under dangerous such as emission of toxic gas. And because safety is a requirement of any profession, it was necessary to provide a little something that contributes to the protection of workers. Smart helmet will be very useful product, equipped with many main characteristics: 1 . Automatically, will detect the increase of CO2, high temperatures and accelerated heartbeat. As a result, it will: a. warns workers with a bell sound or light. b. sends a warning to the company responsible for the factory informing them of this problem through GSM module connected with Arduino that sends SMS messages (warning messages) to mobile. 2 . Automatic lighting in dark places 3 . Automatically, provide a normal mask in case emission of toxic gas to prevent workers from inhalation gas. 4 .Detect the location of workers that wear helmet and send location to the server company . In order to do this project, some equipments and hardware tools will be used to facilitate the process such as: 1. Arduino Uno. 2. Some Sensors like Temperature Sensor (TMP36), CO2 Sensor to detect the increase of CO2, Pulse Sensor to measure heartbeat , LDR resistor (sensor) to detect the dark places and GPS sensor to detect location .. 3. Servo Motor will be used to make the mask fall to worker to protect him from toxic gas. Design: Smart helmet composed in the front end a light that turns on in the dark places,beside it there's a servo motor that includes the mask that protect workers from toxic gas.Also, there is a piece connected with ear to detect the accelerated beats to make sure that workers safe.