ACEIRMC ADS1115 16 Bit 16 Byte 4 Channel I2C IIC Analog-to-Digital ADC PGA Converter with Programmable Gain Amplifier High Precision ADC Converter Development Board for Arduino Raspberry Pi (2pcs)

This is falsely stated as having an ADS1115 converter, which is a 16 bit converter. Instead the chip on this board is an ADS1015 (or equivalent), which is a 12-bit converter.As can be seen from the datasheet for ADS1015, the low order 4 bits are "reserved" and are always reported as 0. So this will go up in steps of 16 when you read the raw output.ADS1015 is a great chip, and if what you want is a 12 bit conversion, this is awesome - it's even a good price for a 12-bit converter, and I would have bought it and given it a 5 start rating if they had just said it is what it is.Also it is software-compatible with the ADS1115, so if you search for any of the several libraries in the Arduino ecosystem you'll find plenty of support for it.Note that the ADS1x15 family are all pseudo-differential. You can compare input A0 to A1 or A0, A1 or A2 to A3, or compare any of the four to ground. However the output is a signed integer, meaning if you compare a positive voltage to ground you will always get a positive value, but it will only be half the range (ie. your 12 bits are now only 11 useful bits). Consider comparing to a reference voltage in the middle of your desired range, or accept that what you bought as 16 bit ADC is effectively an 11-bit ADC.

I've had one of these running for about a week straight now with no issues. Accuracy is good and only the lest significant bit shows any sign of noise, not bad. Programming was simple to get running on an MSP430. Overall, I am impressed.

Code Library load to IDE & remote module's Analog function provided the much needed resolution and accuracy after calibration. Lots of You-Tubes to review on a WEB search, helped provide insight into additional uses.

monitoring pressure and flow on a test rig

Received two chips labeled ADS1115, both are not 16 bit. Serial monitor in Arduino increases to 32,768 full scale (as expected), however the data jumps by 16s, giving a resolution of 16 instead of 1. This chip is labeled as a 16-bit ADS1115, but only functions as a 12-bit ADS1015. This is false advertising. For some 12-bit might be totally adequate, but I require much greater precision for my current project, rendering this chip useless.

hook it up and configure it as if it's a 16 bit adc and all the raw output values are multiples of 16 (0b10000) those last 4 missing bits don't exist because this is a 12 bit ads1015but as a 12 bit adc it works just fine!