I am working on a project to read analog sensors. I need to read them and convert them to digital values and transmit them to the server and do the processing there. I need a ADC chip that can give out digital voltage or something that I can read through the GPIO of ESP8266 so that I can reject the MCU part in here. I cannot use the ESP's ADC pins as my input ADC voltage is little higher and also I don't want an extra circuit to be added in this. I just wanted to know if some chip like that is available that I can use it for my project. Thanks in advance.
closed as unclear what you're asking by Dmitry Grigoryev, Bence Kaulics, Daniel Grillo, pipe, Sparky256 Aug 3 '16 at 20:02
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How about an external ADC connecting to the I2C bus? Check this one out, it fits your criteria (plugs into digital pins on the ESP and literally converts analog signals to bytes over I2C) and even has an Arduino library written for it by Adafruit - might work out of the box with ESP but I'm not 100% sure.
There is no need for an external ADC. Simply use a voltage divider on the ADC input. If the ADC input accepts 0 - 2.5 volts, divide the 0-5 volt signal by two, as follows:
By chaning the resistor values, you can get any ratio (<1) you wish.