Shimano's Di2 Canbus protocol - advances on hacking it?

Discuss light weight issues concerning road bikes & parts.
dale79
Posts: 18
Joined: Fri Jul 19, 2013 7:52 am

by dale79

yeh ok mate, maybe you should stick to aircraft..

srams electornic groupset is awesome.. lol

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andy2
in the industry
Posts: 713
Joined: Sun Dec 16, 2007 9:33 pm
Location: Luxembourg / Sweden

by andy2

Good thinking on the sprint shifters!
What if there is no CanBus protocol and the system is coded in another fashion...?

/a



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rolobikes

by Weenie


goodboyr
Posts: 1388
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

Does this mean that if you have 9070 shifters with the extra plug for the sprint connection that you could splice regular switches to cables and plug them in to get remote shifting?

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dale79
Posts: 18
Joined: Fri Jul 19, 2013 7:52 am

by dale79

That's correct,

freeloader
Posts: 46
Joined: Mon Dec 31, 2012 5:27 am

by freeloader

Another function which would be useful is the option to set system so it will not shift into a cross-chain situation (big-big, small-small), another advantage to mechanical setup...

I find that the move towards electronics offers lots of possibilities yet to explore :) -

1) hub dynamo to charge the battery
2) accessories (lights, GPS etc) backed up with Di2 battery
...
...

teufelhunden222
Posts: 83
Joined: Thu Jan 10, 2013 9:16 pm

by teufelhunden222

dale79 wrote:yeh ok mate, maybe you should stick to aircraft..

srams electornic groupset is awesome.. lol



If you want to be a dick I can play at that game as well. Yes I would buy a shifter just to take apart just to be a dick.
[img]<iframe%20height='160'%20width='300'%20frameborder='0'%20allowtransparency='true'%20scrolling='no'%20src='http://app.strava.com/athletes/1677950/activity-summary/ddf436fc1ca509b20d4637cfa80c928da771d2c6'></iframe>[/img]

teufelhunden222
Posts: 83
Joined: Thu Jan 10, 2013 9:16 pm

by teufelhunden222

http://fairwheelbikes.com/forum/viewtop ... 0&start=75
For the anti selling things that are already public domain.
[img]<iframe%20height='160'%20width='300'%20frameborder='0'%20allowtransparency='true'%20scrolling='no'%20src='http://app.strava.com/athletes/1677950/activity-summary/ddf436fc1ca509b20d4637cfa80c928da771d2c6'></iframe>[/img]

teufelhunden222
Posts: 83
Joined: Thu Jan 10, 2013 9:16 pm

by teufelhunden222

Only a pulse and square wave are used for the RD, more info as I get it
[img]<iframe%20height='160'%20width='300'%20frameborder='0'%20allowtransparency='true'%20scrolling='no'%20src='http://app.strava.com/athletes/1677950/activity-summary/ddf436fc1ca509b20d4637cfa80c928da771d2c6'></iframe>[/img]

kulivontot
Posts: 1170
Joined: Sun May 16, 2010 7:28 pm

by kulivontot

Fairwheel Bikes did a sequential DI2 hack for a mountain bike, so I'm pretty sure somebody's been able to reverse engineer this stuff. I doubt it's really that complicated of a protocol, who needs to encrypt switch signals?

goodboyr
Posts: 1388
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

That fairwheel thread is about non canbus di2. Apples and oranges.

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freeloader
Posts: 46
Joined: Mon Dec 31, 2012 5:27 am

by freeloader

i heard this story and thought it might be beneficial -

##################
A man was driving along some street in Brooklyn, New York, when another car suddenly cut into his lane. He had to brake hard and almost crash into the other vehicle. The other person drove off without apologizing. He was furious. He chased down him down the streets, got close a few times to shout expletives which probably Mike Tyson or Madonna wouldn't utter. He finally managed to force the other car into a stop at a red light. He rushed out of his car towards the other driver. The other driver was really scared. He rolled up the windows, but that didn't prevent the angry man from banging on his car, shouting vulgarities while doing that. The angry man was going to beat the hell out of him if he got hold of him.

Luckily the traffic lights turned green, the scared driver sped off instantly. The angry fellow had no chances of catching him this time round. He walked back towards his own car, cursing and swearing along the way. But his car was nowhere to be found. All of a sudden, he realized that the key was left in it when he jumped off his car. Someone must have seen that and drove off with his car. In the busy streets of Brooklyn, nobody leaves the car key on.
##################

How often have we been the angry driver who lost his car?

In cyberspace, we are "shielded" from angry fists, but it still hurts, sometimes more...

dale79
Posts: 18
Joined: Fri Jul 19, 2013 7:52 am

by dale79

teufelhunden222 wrote:http://fairwheelbikes.com/forum/viewtopic.php?f=3&t=7580&start=75" onclick="window.open(this.href);return false;
For the anti selling things that are already public domain.


once again soo far off the mark its not funny..

Dura ace 7900 DI2 is totally different signal and can add buttons no problems at all..

drmutley
Posts: 344
Joined: Fri Feb 11, 2011 4:23 am

by drmutley

Guys, if your going to take pot shots at dale79 at least do some fin homework... Its embarrassing....

He's emulating the canbus protocol which ui2 uses. I am unaware where anyone has released how to do this in the other, long running threads on various forums. So stop making a dick of yourself. No it's not easy to do, otherwise after 12+ months everyone would be doing it. When it seems no one has the nous, nor spent the time to work it out, then he's entitled to do what he wants with his IP.

So back to the original question - Anyone care to post HOW ITS DONE?

(Not just surmise that it must be "easy" to do)

nickl
Posts: 140
Joined: Fri Jan 18, 2013 12:37 am

by nickl

teufelhunden222 wrote:I am a avionics guy on f-18's. Pretty sure I could figure it out. its just an electronic interface aka a button. There is not a huge selection of possibilities given the number of wires available to work with. purely guessing I would speculate that they either use a common power or ground and feed it back along different routes to indicate what is being pressed. least wire count that way. But I could really give a shit about shimano, sram makes a lighter better product.


Ha. Remind me not to fly any FA-18s you have worked on lately.

This isn't an analogue signal. Read https://en.wikipedia.org/wiki/1-Wire (Di2 doesn't use 1-Wire, but the principle is the same).

dale79 has done some good work here.

drmutley
Posts: 344
Joined: Fri Feb 11, 2011 4:23 am

by drmutley

nickl wrote:
teufelhunden222 wrote:I am a avionics guy on f-18's. Pretty sure I could figure it out. its just an electronic interface aka a button. There is not a huge selection of possibilities given the number of wires available to work with. purely guessing I would speculate that they either use a common power or ground and feed it back along different routes to indicate what is being pressed. least wire count that way. But I could really give a shit about shimano, sram makes a lighter better product.


Ha. Remind me not to fly any FA-18s you have worked on lately.

This isn't an analogue signal. Read https://en.wikipedia.org/wiki/1-Wire" onclick="window.open(this.href);return false; (Di2 doesn't use 1-Wire, but the principle is the same).

dale79 has done some good work here.


+1 Haha

by Weenie


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