SparkFun microSD Shield Category_Grove (Arduino)/Grove Potenza An external humidity sensor is

An external humidity sensor is required and then the RH% is written over I2C to the sensor

and a 2x4 header + jumper to change the amplifier gain on the fly

20+4 including 8 GPIOs which can be input

you can chain the data lines while separately powering shorter subsections of the chain

SparkFun microSD Shield Category_Grove (Arduino)/Grove Potenza An external humidity sensor isRunning out of memory space in your Arduino project? The SparkFun microSD Shield equips your Arduino with mass storage capability, so you can use it for data logging or other related projects. Communication with microSD cards is achieved over an SPI interface. The SCK, DI, and DO pins of the microSD socket are broken out to the ATmega168 328\'s standard SPI pins (digital 11 13), while the CS pin is broken out to Arduino\'s D8 pin. If you decide to use