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+This project is about interfacing a bathroom weight scale with the computer.
+The goal is to be able to connect the scale to the computer and have it sent the weight it measures.
+
+The scale used is a Korona KFW-55.
+This scale was simply around when the project started.
+
+To connect the scale to the computer a Arduino Nano development board is used.
+The Atmel ATmega 328P micro-controller is integrated in the scale case.
+It reads the PWM signal, interprates the weight, and sends it on UART (over USB).
+
+The scale has a JP1 header on the board.
+Pin 1 is the one near the switch.
+The pinout is the following:
+1. ground
+2. low
+3. high on power on
+4. high on power on
+5. PWM
+6. high on power on
+
+The scale's IC provides a Pulse Width Modulated (PWM) signal.
+This encodes the weight measures.
+It's frequency is around 3 Hz (it's not exact).
+The high and low duty cycle encode the current weight measured.
+The high duty cycle decreases when the weight increases.
+The low duty cycle increases when the weight increases.
+The low duty cycly is linearly proprotional to the weight.
+It still needs a minimum weight to start measuring correctly.
+The origin of this linear curve is not at 0.
+
+The micro-controller code is written in C.
+It reads the state of the scale usinf pin 3.
+It reads the weight on the scale using pin 5.
+By programming the curve parameters in the code it can calculate the weight.
+These parameters have been experimentally identify, using the measured values in `scale.ods`.