Show HN: PJDL an open alternative to 1-wire with a range of 2000m | Hacker News Reader

Show HN: PJDL an open alternative to 1-wire with a range of 2000m

github.com

337 pointsgioscarab16 comments

This is really fucking cool, I thought I was weird for wanting to run a CAN bus in addition to Ethernet for cheap uC's without TCP/ip.

If you run ethernet cable, you are actually running 4 good quality twisted pairs.

You can reuse pairs from Cat5/6 cable for CAN, or RS485 or PJDL or whatever. The same cable could carry 4 such buses (so you could have all of them in the same cable run). Try to use pairs that are twisted in the cable (for eg blue / striped blue)

Yes I did so in my setup I have used CAT5 in star configuration all inserted in wall ducts alongside power cables. I can see some AC interference induced but pull-down resistors are able to erase that completely. I have dedicated 3 wires for the power supply +9v, 3 for ground and 1 for communication.

Off topic, but "for eg" is like saying "ATM Machine"; "e.g." already means "for example": https://simple.wikipedia.org/wiki/Exempli_gratia

Yea but I need all 4 pairs for gigabit and the other upside for CAN is that it actually works in a ring topology. I'd probably run a cheap cat3 cable.

More info here: https://github.com/gioblu/PJON/ Let me know what you think :)

The first paragraph of the readme says it works over USB, but I couldn't find any more information about that. Is USB actually supported?

I recently had a project where I needed the arduino to send data to a computer and ended up using MIDI over USB. There is a way to use USB as a generic serial pipe, but MIDI was really simple to use on both the Arduino and the computer. If it would be accepted into the project I could write a MIDIUSB strategy.

USB is supported with the use of Serial for all arudino compatible devices. A MIDIUSB strategy would be cool, that is a nice suggestion.

Thank you ;) if you need my support join out gitter chat here: https://gitter.im/gioblu/PJON

Sad that this post even getting more than 200 points haven't reached the front page. I must have been mistakenly flagged for some reason.

I think it's because only a minority of readers understand what this project is about! Your explanation is very technical, and the title doesn't really draw attention to itself...

Why is this technology useful? What can it do? Can you explain it in a way a child could understand? And can you also think of a silly or crazy use case for it?

> if(!sync() || !sync() || !sync()) return SWBB_FAIL;

I don't know why, but I find this really elegant. It's a lovely use of short-circuit returns combined with the electrical protocol to find the frame initialiser (3 syncs) that marks the start of a valid frame.

This is a really cool implementation!

Added to list of projects to keep in mind in future. Great work.

Thank you very much will :)

This is incredible. I don’t think people grok how momentous this is. We can transition to a better internet with this. Wow. Thank you.

Thank you very much for seeing good information. https://itcurate.com/top-4-technology-trends-in-healthcare-2...

This would simplify automotive wiring quite a bit.

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