How we made the PJON network protocol from scratch

> over 200 smart sensors and devices around my house

I need to know!

Here you can find the implementation of PJDL used by Jack Anderson to determine the maximum range:

https://github.com/gioblu/PJON/tree/master/src/strategies/So...

All devices listed in the compatibility section are able to communicate over a twisted pair with no additional hardware, as Fred well noted, you just need one wire and connect directly the IO pins. And up to 255 devices can share the same twisted pair.

As you can read in Video Camera Control Jack just used two arduinos, 2km of wiring within his university's network and a couple of pull-down resistors. The protocol works even when the human body is used as a conductor as shows the gif present in the article.

On social compare someone made this: https://socialcompare.com/en/comparison/comparison-of-networ...

I think the comparison between PJON and LIN there is revealing. As you can see LIN handles up to 16 devices, it is master-slave and has a range of 40, with a complex front-end at a relatively high voltage.

PJON is free for use, it is all open-source. We do sell products to fund the development of the project.

Thank you for your feedback, happy to know it helps :)

Ciao jlgaddis Jack in Video Camera Control used PJON over PJDL which is a wired data link that needs only ground and a data cable to connect up to 255 devices, cables can be up to 2km long at the slowest baudrate (1.97kB/s - 15808Bd). PJDL in few words is a sort of open 1-Wire with a longer range, support for more devices and a stronger immunity to noise. See: https://github.com/gioblu/PJON/blob/master/src/strategies/So...

The core of the community uses PJON over PJDL in home automation systems, irrigation systems, feeding systems ecc. Soon Mysensors will include PJON over PJDL in their list of supported transports. PJON works also over TCP, UDP, MQTT, ESPNOW, LoRa ecc. so generally a router is built and programmed to run 2 instances of PJON for example PJDL and MQTT, to then route data to and from a process running on a real-time operative system

See: https://github.com/gioblu/PJON/blob/master/examples/routing/...

which can also run PJON thanks to the wide support of the implementation.

See: https://github.com/gioblu/PJON/wiki

Looks to be handy for many to connect devices, even on different media.

Although many also use PJON to implement mesh or peer-to-peer networks, there is a group in Australia building such a network using PJON over LoRa.

I must say I hope we will be able to start building a private network infrastructure with it, that would be awesome.

Companies and institutions are also implementing PJON within their products and services. AD24, a Czech company, recently created a mesh network over PJON to connect advertising monitors around the city of Prague. It looks there are also few companies in Germany which use PJON to create real world automation systems.

Recently contacted by the Universitat Politècnica de València (UPV) to support the development of a PJON network of temperature and humidity sensors to monitor the vault of the Cathedral of Valencia and avoid its decay, I hope this will end up done, it would be really rewarding.

The main thing that originally sparked my interest in PJDL was multi master, which is clearly a massive advantage over 1-wire

I have used PJON, with the SWBB and DUDP strategies, for my home automation setup for at least 4 years. I do not need the kilometer range of SWBB, but have stretches of tens of meters running alongside 220V AC wires with no problems, in both star and daisy-chained topologies. The system is very stable, and I would like to point out that the alternatives I looked at before required me to buy extra hardware/shields that cost more than the Arduinos themselves to get going. With PJON it is just connecting to the pins in the most inexpensive way. This plus multimaster, the strength against interference, the long cable lengths and few topology limitations makes it a clear choice for many purposes. Plus, it is free :-)

All created between a 8 hour range. Definitely something fishy going on.

I have been here a lot longer than that, and I do recognize some of these comments coming from long-time PJON users parttaking in the PJON gitter channel, asking for advice from other users, asking for new features, etc.

What is wrong with users of an open-source library commenting on the library? Who is better qualified to comment, and what is to be gained -- it is open source, free for all?

I am the author of the report I linked in another comment, if you care to verify please visit the website linked from the report and use the email address there to contact me. Hopefully the size and detail of the report will show I am genuine.

> It's beyond suspicious that 4 newly created users all have positive experience with PJON and only posted on this submission.

I will freely admit that I am, quite often, overly suspicious when there's a bunch of "green" users commenting (overwhelmingly positive) on a Show HN thread too -- especially when there's any money potentially involved (i.e., a product for sale, seemingly "technical" blog posts which are, in reality, just carefully prepared sales/marketing material, and so on) [0]. To be quite honest, I'm overly suspicious of damn near everything and I particularly despise "spam" of any kind [1].

In this case, though, I don't think there's anything dishonest going on, though [2].

The project has been around for about a decade and there's obviously a community behind it. I only spent about 20 minutes exploring the web site and Git repo and while I don't recall seeing any obvious links to a mailing list, message board, or IRC channel, I'm sure the project has someplace where they "hang out" and collaborate.

To me, at least, it's quite easy to imagine that the founder of the project -- the same person who posted this Show HN, AFAICT -- may have told the PJON community "Hey everyone, I just posted a link PJON to HN; here's the URL if anyone wants to join the discussion ..." or something else similar to that. I don't know whether something like happened here or whether the PJON users who just created their HN accounts to comment in this thread discovered it via some other means. I do think that there are several possible explanations that are more likely than all of them being (paid) shills for a piece of software that's both free as in speech and free as in beer [3].

Personally, my own smell test considers things like "what's being promoted?", "what's the real benefit/goal of posting this here?", and, of course, "who benefits from this and in what ways?".

As I said before, I don't have any doubt that there's an ulterior motive here -- the goal seems to simply be to share and promote an ~10 year old open source implementation of an open network protocol that 1) is exactly the type of thing that's generally of interest to HN'ers, 2) was founded on ideals and principles that many of us here on HN share and believe in (autonomy/self-hosting/decentralization), and 3) has (verifiably) been used, successfully, in the real world.

Besides, HN guidelines implore us all to extend the benefit of the doubt. Blatant, obvious "violations" should obviously be pointed out -- but this isn't one of them.

In fact, this project is EXACTLY the type of project that belongs on HN. It's a damn shame that it's now "[flagged]"!

It's almost as if "somebody" doesn't want projects like this one to succeed. Who would benefit if PJON and others like it didn't exist? Who would benefit if users instead had no other option but to pay a for-profit company for the hardware, software, and (of course!) the recurring monthly subscription fee instead of just doing it themselves? Hmm... (see how easy that is)?

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[0] Hell, I get annoyed when User A posts a "Show HN" for their new project and then User X (and, sometimes, User Y and User Z) takes advantage of the "opportunity" to post a "This is similar to $foo, $URL, which is an [app|company|service] that also does $thing" comment in the thread ("Submit your own Show HN, then!" is what I want to say!). Bonus points to those who somehow manage to work in a reference to their own product/service even when the two have only the most minimal of commonalities or similarities ("Interesting. Our service, $bar, is also a web site" is only a slight exaggeration).

[1]: Spam doesn't just arrive via e-mail. To me, "spam" is rather loosely defined and includes any unsolicited and/or unwanted sales/marketing/promotional material (or similar) and, in some cases, even includes anything "off-topic" (depending on the forum, usually).

[2]: My HN account is only ~8 years old and I only lurked for a few years before I finally decided to devote the time, effort, and energy necessary to create an account. I'm not sure if that's long enough to pass your "shill test" or not; If necessary, I would sign a sworn affidavit attesting that I had never even heard of PJON before today but, then again, that's just the kind of thing a shill would say!

[3]: It's available under the Apache license.