added manual

- hardware list
- software requirements

README.md

@@ -1,3 +1,40 @@
 # FTDI_simple_alarm
 
-Use an USB-Serial Converter like the FT232RL for activating an buzzer. 
+Use an USB-Serial Converter like the FT232RL for activating an buzzer. Simple and cheap (~1,75€)
+
+## Features:
+* works on GNU/Linux only
+* no drivers or other software/libs are requidered
+* triggerd via bash or service daemon
+
+## Limitations:
+* works safe on system with only one /dev/ttyUSB device
+* no other task can use the FTDI device for other things
+
+## Handware:
+1. FT232RL Breakout board ~1,5€
+2. NPN Transistor like 2N2222A ~0,0€
+3. Active Buzzer 5V ~0,25€
+
+### Schematics:
+
+## Software:
+
+### Commmon Distributions
+
+Make shure the device is recocntied as ttyUSB after plug in with `dmesg`.
+Edit the alarm.sh with your device name, like `/dev/ttyUSB0` 
+run `bash ./alarm.sh` for starting the alarm.
+
+### openWrt
+
+`opkg update`
+`opkg install kmod-usb-serial`
+`opkg install kmod-usb-serial-ftdi`
+
+Make shure the device is recocntied as ttyUSB after plug in with `dmesg`.
+Edit the alarm.sh with your device name, like `/dev/ttyUSB0` 
+run `bash ./alarm.sh` for starting the alarm.
+
+### Service
+todo