- #TWO WIRE INTERFACE ARDUINO SOLDERING SOFTWARE#
- #TWO WIRE INTERFACE ARDUINO SOLDERING PLUS#
- #TWO WIRE INTERFACE ARDUINO SOLDERING FREE#
If you want to use the analog output of the rain sensor, things get tricky. Can't really tell what the limit of the cable length would be. The digital output of the rain sensor should pose no problem, it has a high drive strength and as it is a simple high / low push pull output.
#TWO WIRE INTERFACE ARDUINO SOLDERING SOFTWARE#
It might be that you have to adapt the software or change the pull-up resistor to cope with the longer cable. YL-83 - erm just a digital it rains / it doesn't rain pin? - or an analogue voltage output (how much does it rain)įor Onewire there is an application note available which describes the operation over long distances, I'm not entirely sure if that principle can be applied to the said sensor, but I guess 20 meter should be doable, they are able to get 200 meter out of that. Okay based on the sensors you are using you have the following interfaces: Given that there is not high volumes of data here, reducing the transfer speed would help over this distance - you could for example use dI 2C or 1-wire to interface the MCU over the cable as long as you run the bus slowly (10kHz maybe) to allow signals to propagate and settle. In any case if you combine the sensors together you would only have one interface. Once you send the response, you switch back into RX mode and await further instructions by the master. At which point you collect and send information about the sensor values.
#TWO WIRE INTERFACE ARDUINO SOLDERING FREE#
You would tie the DE and !RE pins together and to one I/O pin (transmit/receive mode select), and tie the DI/RO pins together to the other free I/O pin which would be a bidirectional data-in/data-out line.įor both options you could for example sit in receive mode until instructed to transmit by a master at the other end of the cable.
#TWO WIRE INTERFACE ARDUINO SOLDERING PLUS#
Plus it means you don't need an external driver. Implement RS-485 directly using the 2 free I/O pins of the MCU - this should be do-able from an electrical standpoint, and is not that difficult to implement in software. You would have two (maybe more) options for doing this: In this setup you would have half-duplex communication. I would suggest something like RS-485 to do this as it is designed to be a differential I/O standard and should work fine with a CAT6 cable - you would have to make termination \$100\Omega\$ otherwise signal reflections would be quite problematic. The ATTiny85 has only 6 I/O pins, so you would have 2 left to interface with the other end of the cable.
But then you would also need an interface through the cable. You would need at least 4-pins for your inputs (1 is an ADC, 2 for the I 2C interface, and 1 for the 1-wire bus). Something like the ATTiny85 would be quite compact being only an 8-pin package, but you would have to look at how many I/O pins are required. My suggestion then would be to add an MCU at the end of the cable to interface with all of the sensors. As per this Maxim application note, 1-wire should be possible (thanks for point that out) over that length with some care. Though having re-familiarised myself with the specification, this may be the only one of the three which would could reliably interface over 20 metres as long as you are careful with crosstalk and noise. There is a method called dI 2C or differential I 2C, using the PCA9615 chip, but that is only rated for about 3 metres.Īnalogue will be terrible unless you buffer it (and probably even if you do) - voltage drop across the wire from any load imparted by the ADC, and more crucially noise caused by crosstalk with the digital lines amongst other things.ġ-wire has similar limitations of I 2C. It is especially problematic over twisted pair as the crosstalk between lines will completely kill it. I 2C is designed for short interconnects (inter-intergrated circuit!) not long runs. Over 20m, all of these are tricky (though not impossible)
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