Transfer Power and Digital Signals Over 15 Meters with μDiff
Alexander Williams' μDiff provides easy way to reliably relay power and a digital signal over a long distance via an RJ45 cable.
We have been using RJ45 cables (Ethernet) to transmit information along the length. Alexander Williams' μDiff has come into light due to the lack of hardware that can control small devices and LEDs over a 15-meter distance. Also, the reliability and simplicity of using RJ45 cables to connect multiple devices can be more efficient over wireless signals. In short, μDiff is a low-cost and compact board that can transfer power and digital signal over a long distance.
The minimalistic design employs RS-485 differential signalling and 802.3af mode B pinouts. RS-485 signals prevent the problems of ground loops and common source of communication. Differential signaling and twisting allow the RS-485 to communicate over long distances and can go up to the distance of 1200 meters. With differential signal lines, there can be higher data rates for transmitting the information as well.
μDiff takes the input voltage between 8V-28V gives the output of 5V and 3.3V, which becomes one of the most highlighting features. With this, each module can be powered 3.3V and 5V devices from a single power source. The eight-pin headers are provided to access the output voltages, ground and RO, RE, DI, and RE signals.
“Current is limited to 1A with the default components, but can be upgraded to ~2A with a different 5V switching regulator and fuse," Williams writes. "Beware of current limitations on the RJ-45 cable, it's typically ~700mA for an AWG26 shielded wire pair (2 wires).”
The board can be used for remote applications due to its small form factor of just 50mm x 44mm. It is important to note that the hardware is not PoE (Power-over-Ethernet) compliant and cannot negotiate voltage levels like PoE. If you are interested in getting this inexpensive hardware for your applications, head over to Williams' Tindie page where it is priced at just $10.
