documentation update, schematic/layout as image

Hardware/README.md

@@ -69,7 +69,7 @@ compiled using Arduino 1.8
 
 ### Hardware
 
-Schematics (KiCad) here: [schematics](schematics/) 
+Schematics (KiCad) here: [Schematics](Schematics/) 
 I also created a PCB layout, despite I only built a prototype on breadboard, as it speeds up this process by far. It can be found in schematics folder. 
 
 - based on Arduino Pro Mini (or clone, with ATmega 328p MCU)

Hardware/Schematics/README.md

@@ -0,0 +1,27 @@
+# DualS0ImpCounter - Hardware
+
+Arduino based hardware for capturing impulses from S0 impulse meters. 
+
+### Hardware
+
+- based on Arduino Pro Mini (or clone, with ATmega 328p MCU)
+- power supply using a 12VDC wall plug
+- big buffer capacitor only for the MCU itself, right before it´s diode decoupled 5VDC regulator, 
+- resistor network from 12VDC supply to ADC input to detect power loss early enough
+- 2 S0 impulse inputs using optocouplers, active LOW (compatible with S0 outputs, which are usually open collector outputs)
+- connection to host over RS232, so **NOT USING USB POWER SUPPLY**
+- RS232 connection **without DTS signal**, so that the MCU cannot be surprise-reset by the host on (re-)connect
+- reset circuit (connection from a GPIO out to /RES input)
+
+
+
+### Schematic
+
+![](Schematic.png)
+
+
+
+### Board Layout
+
+![](Board.png)
+