Description

Ever had a I2C sensor a little further away? Then line drivers are your answer. This one is based around the PCA9600. You can also use it to connect 5V devices to a 3.3V controller. There is even an optional LDO to supply your remote sensor.

Attention: if you want to use this design as a line driver, you need two of the PCBs.

The PCA9600 is isolating the line voltage from the local voltage. So you can go with 12V VCC_LINE and use 3.3V VCC.

If you solder JP1 shut, then the VCC_LINE will be shorted to VCC.

Technical details/Needed components

U2: PCA9600

R3 & R4: 0805 SMD resistors. Use 330 Ohm for 3m telephone cable. Else, calculate according to PCA9600 datasheet.

Everything else is optional!

R1 & R2: Pullup for the local I2C

C2 & C3: Capacitors for SCA and SDL

To supply the remote sensor directly from the line voltage, solder JP1. If you want to supply the remote sensor over a LDO, then use:

U1: AMS1117

C1: 22u tantalum 1206

For example, I use a line voltage of 5V and a AMS1117-3.3 to supply a GY-63 and a SHT35 three meters away from the main cabinet with the ESP8266.

Build Instructions

Should be straight forward. For the PCA9600, it works best if you don't solder each pin individualy, but have some solder on your iron and much flux over the pins. Then go smoothliy over the pins and they will be soldered.