pretty cool Keith. I've never thought of spinning something like this myself before, but I like the way you're doing it. My only concern is just how hard you can yank the bus around given it's capacitively coupled. I can imagine a scenario where the stray capacitance of the frame of the bike or just the length of a run ends up nuking your SNR, but I also don't think that would happen at the frequencies and edge rates you're running. Also, love the nRF, such a good chip.
I've been doing some testing with other protocols and methods and recently simulated some more advanced methods to increase speed. I'm still digging further into this. This isn't the end of it.
Yes / No. Previously on the Kommander Product I used MMCX connectors that were potted on the pcb side. This proved to be very waterproof but it had the problem that the actual electrical connections were exposed when nothing was plugged in and when something was, the electrical connections were still sort of exposed. So I'm looking at ideas to refine that.
Do you really need the bandwidth with the square edges? I imagine the quiescent and active power losses will be rather high? Have you looked at HART protocol? It modulates a carrier between 1.2k and 2.2k standard serial data between modems on top of typically a 4-20mA current loop but no reason why it can't be used on top of a higher voltage system.
Liked your video and was wondering if this could be piggybacked on another type of AC such as an audio signal - 20 to 20KHz. If there's a product that already does this, please let me know but if not, I'd like to apply this to a line level, balanced, microphone cabled signal. The audio signal is limited to around 16KHz so could a data carrier frequency say around 20KHz be mixed (if that's the right term) with the audio without affecting anything below 16KHz while still being able to pull off the 20KHz carrier?
by the way, there is a device that sends ethernet over the mains powerline. i don't know if you knew about that, you probably did. possibly leads to more research papers you can study
I'm familiar with these parts. They are on the order of hundreds of milliwatts to watts continously.... So a SRAM AXS style battery would work for 2 - 3 hours just for comms.
Unfortunately you are wrong. Canbus cannot theoretically and does not practically work with powered buses (future video). This is a falsehood that is being spread by armchair fake-genieers on forums who are regurgitating wrong info. Canbus is a differential signaling that cannot carry power and meet the electrical specifications because its spec literally requires CanH and CanL to basically the same voltage -- this avoids idle current due to the required terminations. So no data = there must not be voltage thus you cannot power anything whatsoever. There are some mythos going around that Shimano DI2 "etube" was canbus. It wasn't and never was. The non-etube DI2 7970 10spd used 5 pins, and was possibly, but unconfirmed, said to be Canbus. So no. Canbus cannot carry power. This is 100% wrong.
i am sure this technology needs to find a way in to the home assistant / home automation world. using wifi on 100 different automation devices sucks any way you slice it and you have to run the power lines anyway
For that you can just use ethernet with PoE. One off-the-shelf cable for data and power. If you know what you're doing you can also inject 5V into the unused pairs of a 100Mbit cable
10Base-T1 -- that 1 is important distinguister.. .or maybe its the S part of T1S? either way it's hundreds of milliwatts. So your month of riding turns into a couple of hours for normal electronic groupsets -- not that viable. I need microwatts on average. Normal POE requires 4 wires because they center tap the transformers on the magnetics so one pair is signals +48v and the other effectively grounded.
I've learned so much from you over the last 10 years!
Thanks I learned a little bit about my earbuds
awesome work!
pretty cool Keith. I've never thought of spinning something like this myself before, but I like the way you're doing it. My only concern is just how hard you can yank the bus around given it's capacitively coupled. I can imagine a scenario where the stray capacitance of the frame of the bike or just the length of a run ends up nuking your SNR, but I also don't think that would happen at the frequencies and edge rates you're running. Also, love the nRF, such a good chip.
I've been doing some testing with other protocols and methods and recently simulated some more advanced methods to increase speed. I'm still digging further into this. This isn't the end of it.
Fantastic! Is there an off-the-shelf connector you've found? 2 wires, waterproof, round,
Yes / No. Previously on the Kommander Product I used MMCX connectors that were potted on the pcb side. This proved to be very waterproof but it had the problem that the actual electrical connections were exposed when nothing was plugged in and when something was, the electrical connections were still sort of exposed. So I'm looking at ideas to refine that.
How about the FAKRA series connectors?
Good content. This is how many RF systems send power through an antenna connector (e.g. SMA) to add powered LNAs. Many GNSS systems do this.
Do you really need the bandwidth with the square edges? I imagine the quiescent and active power losses will be rather high? Have you looked at HART protocol? It modulates a carrier between 1.2k and 2.2k standard serial data between modems on top of typically a 4-20mA current loop but no reason why it can't be used on top of a higher voltage system.
Two wire takes a lot of wires.
One-Wire technically also needs two wires.
Liked your video and was wondering if this could be piggybacked on another type of AC such as an audio signal - 20 to 20KHz. If there's a product that already does this, please let me know but if not, I'd like to apply this to a line level, balanced, microphone cabled signal. The audio signal is limited to around 16KHz so could a data carrier frequency say around 20KHz be mixed (if that's the right term) with the audio without affecting anything below 16KHz while still being able to pull off the 20KHz carrier?
add preamble and whitening for DC0 sum
👍🏻
8Mhz carriers on long wires will radiate and would probably not pass any radiated emissions qualification required for a commercial product.
Yes that's the Achilles heel...
It's cool to use two wire but that communications component is going to screw up EMI
by the way, there is a device that sends ethernet over the mains powerline. i don't know if you knew about that, you probably did. possibly leads to more research papers you can study
I'm familiar with these parts. They are on the order of hundreds of milliwatts to watts continously.... So a SRAM AXS style battery would work for 2 - 3 hours just for comms.
So a canbus.
Unfortunately you are wrong. Canbus cannot theoretically and does not practically work with powered buses (future video). This is a falsehood that is being spread by armchair fake-genieers on forums who are regurgitating wrong info. Canbus is a differential signaling that cannot carry power and meet the electrical specifications because its spec literally requires CanH and CanL to basically the same voltage -- this avoids idle current due to the required terminations. So no data = there must not be voltage thus you cannot power anything whatsoever. There are some mythos going around that Shimano DI2 "etube" was canbus. It wasn't and never was. The non-etube DI2 7970 10spd used 5 pins, and was possibly, but unconfirmed, said to be Canbus. So no. Canbus cannot carry power. This is 100% wrong.
i am sure this technology needs to find a way in to the home assistant / home automation world. using wifi on 100 different automation devices sucks any way you slice it and you have to run the power lines anyway
For that you can just use ethernet with PoE. One off-the-shelf cable for data and power. If you know what you're doing you can also inject 5V into the unused pairs of a 100Mbit cable
10Base-T1 -- that 1 is important distinguister.. .or maybe its the S part of T1S? either way it's hundreds of milliwatts. So your month of riding turns into a couple of hours for normal electronic groupsets -- not that viable. I need microwatts on average. Normal POE requires 4 wires because they center tap the transformers on the magnetics so one pair is signals +48v and the other effectively grounded.
@@DrathVaderthat's cool and probably what i will do, but daisy chaining man.... daisy chaining....
called KNX, german patent