No has leido tu propio enlace (por cierto lee el privado que te envié).
Ahi dice
PH Limit: This potentiometer is to set a limit value of the pH sensor circuit that causes the red LED to light up and the Do pin signal to turn ON.
O sea, Do es un pin de salida digital que responde a un umbral ajustado con el potenciometro. Si superas ese valor fijado, el led se enciende.
O sea es una salida digital con presete ajustable por el potenciometro.
To es una salida analógica de temperatura que va de 0 a 80 Grados.
Tmb encontré esto
Board description
BNC plug: Where you put the probe. It seems to work with any probe with a calibration difference. I tested 3 models (cheap blue, cheap black and a short black from a EC+pH kit).
Pin To: Should be the temperature but I can't make it works.
Pin Do: High/Low 3.3v adjustable limit.
Pin G/GND: Probe ground. It is useful when the ground is not the same as your Arduino. In some circumstances the ground voltage of the liquid to measure can be different.
Pin G/GND: Power ground (direct from Arduino).
Pin V+/VCC: Input power 5V DC (direct from Arduino).
Blue potentiometer close to BNC: pH offset.
Blue potentiometer close to pins: limit adjustment.
Black component with 103 printed (not the one between potentiometers): thermistor for temperature compensation.
Donde dice que T0 deberia ser temperatura pero no pudo hacer que funcione.
El resto ya lo sabes.
Guardo el esquema para referencia futura.
