PJON
Infrastructure
communication bus protocol
SHOW HN2015
38points
29comments
#750of 2,565 in 2015
Top 30%of 2015 by points
How HN took it
CuriousMostly questions and neutral comments
1 positive, 7 neutral or asking, 1 mixed, 4 critical, out of 13 comments about the project. Thread score -0.11.
Docs: 0 for, 2 againstPerformance: 0 for, 1 againstIdea: 0 for, 1 against
The thread, comment by comment
Each row is a top-level comment and its replies, in HN's order. Select a cell to open that comment on HN.
positive neutral or mixed critical about another commenter or something else the maker
What HN said
What people liked
Useful feedback and thorough protocol critique from commenters
From 2 comments
But quite often the ground isn't the same level at all points in an installation, so you need to run two wires between the two Arduinos. Not picking on you, I'm just saying that…
roel_v on HNSorry, this got long... This looks very interesting as a 'simple' communications protocol, and it would be great to have one available for simple multi-master applications. This…
kbaker on HN
Objections
'One wire' claim ignores need for a common ground wire
From 2 comments
When you say 'one wire', I assume the Arduino's on both ends need to have some common ground? Secondly, is there a way to passively power an Arduino and potentially layer your…
roel_v on HNBut quite often the ground isn't the same level at all points in an installation, so you need to run two wires between the two Arduinos. Not picking on you, I'm just saying that…
roel_v on HN
50 m cable length may cause ground and noise problems
From 1 comment
50 m might definitly lead to problems in other settings. "Because both ends of the RS-232 circuit depend on the ground pin being zero volts, problems will occur when connecting…
jonsen on HN
Lacks timer/interrupt implementation and robust CRC and sampling
From 1 comment
Sorry, this got long... This looks very interesting as a 'simple' communications protocol, and it would be great to have one available for simple multi-master applications. This…
kbaker on HN
No auto-addressing; addresses are assigned manually in code
From 2 comments
I think you should list all the flaws of I2C and SPI and say if PJON also suffers from them: * How easy is mixing 3.3V & 5V? * Can I always program the address of a slave? (If…
IshKebab on HNHi there, this is really a good suggestion, why don't you open a issue on github related to this? To have it working with mixed 3v3 5v you have to choose main channel voltage and…
gioscarab on HN
Requests
Clarify the 'one wire' wording and ground requirement in docs
From 1 comment
But quite often the ground isn't the same level at all points in an installation, so you need to run two wires between the two Arduinos. Not picking on you, I'm just saying that…
roel_v on HN
Publish a written specification or wiki for porting
From 2 comments
I see that it uses Wiring, but I'd be interested what the minimum requirements are for a compatible implementation. For example, would it be possible to implement it without some…
dnet on HNThank you so much for your feedback. I think the first step on ATtiny compatibility can be ATtiny85 with a decent port on wiring. (I think will work also without external…
gioscarab on HN
Support ATtiny85 and lower-memory chips
From 2 comments
I see that it uses Wiring, but I'd be interested what the minimum requirements are for a compatible implementation. For example, would it be possible to implement it without some…
dnet on HNMaking it work for ATtiny85 would be very neat. I've never tried to run it at 16Mhz without an external oscillaror -- only 8Mhz. Would it be a big problem to run the network at…
bborud on HN
Add auto-addressing and collision detection
From 1 comment
Sorry, this got long... This looks very interesting as a 'simple' communications protocol, and it would be great to have one available for simple multi-master applications. This…
kbaker on HN
Correct throughput figures in the readme
From 1 comment
It's 'baud', not BAUD/S. Your signal timing is 20 microseconds which equals a signal rate of 50000 baud, or 50 kBd. There are 12 signals in each frame holding one byte. So the…
jonsen on HN
Questions
What does the accuracy metric measure
From 1 comment
> Accuracy: 99.95% What does "accuracy" mean here? Successful transmission rate?
kaoD on HN
Can it passively power devices over the same wire
From 2 comments
When you say 'one wire', I assume the Arduino's on both ends need to have some common ground? Secondly, is there a way to passively power an Arduino and potentially layer your…
roel_v on HNYes gound is necessary for every connected device. Actually passive power on the same communication wire as 1-Wire has actually is not part of the functionalities of PJON, could…
gioscarab on HN
How the 50 m range was measured
From 1 comment
What does the `accuracy` measurement on your benchmarks show ? How did you estimate max transmit distance of 50m. I know I am pretty negative but to me once you reach this level…
antoinealb on HN
Alternatives named
1-Wire
From 2 comments
Hi there, this is a communication bus system, that transfers data between computers. What is interesting is that is completely software (no usage of hardware components of the…
gioscarab on HNBut quite often the ground isn't the same level at all points in an installation, so you need to run two wires between the two Arduinos. Not picking on you, I'm just saying that…
roel_v on HN
I2C and SPI
From 2 comments
I think you should list all the flaws of I2C and SPI and say if PJON also suffers from them: * How easy is mixing 3.3V & 5V? * Can I always program the address of a slave? (If…
IshKebab on HNHi there, this is a communication bus system, that transfers data between computers. What is interesting is that is completely software (no usage of hardware components of the…
gioscarab on HN
CAN bus and RS-485
From 2 comments
Sorry, this got long... This looks very interesting as a 'simple' communications protocol, and it would be great to have one available for simple multi-master applications. This…
kbaker on HNWhat does the `accuracy` measurement on your benchmarks show ? How did you estimate max transmit distance of 50m. I know I am pretty negative but to me once you reach this level…
antoinealb on HN
Modbus
From 1 comment
But quite often the ground isn't the same level at all points in an installation, so you need to run two wires between the two Arduinos. Not picking on you, I'm just saying that…
roel_v on HN