Tutorial introduction finished

docs/introduction.md

@@ -8,12 +8,26 @@ Let's discover **AnyShake in less than 5 minutes**.
 
 ## What is AnyShake?
 
-TODO
+AnyShake is an open-source project that enables you to build a cost-effective seismograph.
 
-## How AnyShake works?
+## How AnyShake Works?
 
-TODO
+AnyShake utilizes geophone sensors. The AnyShake Explorer collects voltage counts from these sensors, and the AnyShake Observer parses, verifies, streams, and archives this data.
 
-## Why choose AnyShake?
+Geophone sensors measure seismic waves. The AnyShake Explorer employs three geophone sensors to detect seismic activity in three directions (EHZ, EHE, EHN). Each geophone contains a coil and a magnet. As seismic waves pass through the geophone, the magnet moves, generating voltage in the coil. Geophones also have a natural frequency, akin to the resonant frequency of a spring-mass system along their working axis.
 
-TODO
+## Why Choose AnyShake?
+
+Most of the homemade seismographs are based on MPU6050. But MPU6050 is not a seismograph sensor, it's an accelerometer and gyroscope sensor, which is not designed to measure the seismic waves. So, it's not sensitive enough to measure the seismic waves. AnyShake is based on geophone sensors, which is designed to measure the seismic waves, so it's more sensitive than MPU6050.
+
+Many homemade seismographs rely on the MPU6050, an accelerometer and gyroscope sensor not designed for seismic wave detection. Hence, it lacks the sensitivity required for accurate seismic measurements. AnyShake, however, uses velocity geophone sensors specifically designed for this purpose, offering greater sensitivity than the MPU6050.
+
+## Have a Try
+
+Here are some demo sites for you to explore.
+
+ - [AnyShake @ Beibei District, Chongqing, China](https://wolfx.rfotg.org)
+ - [AnyShake @ Chongqing Institute of Engineering](https://dazu.rfotg.org)
+ - [AnyShake @ Institute of Disaster Prevention](https://cidp.rfotg.org)
+
+You can also build your own seismograph using AnyShake by following our tutorial.