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

Discuss light weight issues concerning road bikes & parts.
drmutley
Posts: 344
Joined: Fri Feb 11, 2011 4:23 am

by drmutley

Hi all,
In order to add 3rd party options to the new Di2s, the Canbus protocol must obviously be implemented in the new part/hack etc. has there been any progress made on adding aftermarket stuff/non-shimano, or hacking it recently? Some google searching doesn't reveal much luck. I also notice the Ui2 tuning thread seems to have died over on fairwheel's forum.

An Aussie fella seems to have made an A/D converter to allow cateye sprint shifters with Ui2, but unfortunately he won't shed any light on it (he's probably keen on making a quid out of it which fair enough I guess).

Link here to the thread - http://www.bicycles.net.au/forums/viewtopic.php?t=66075

Anyone know of any devices to make home brew sprint shifters and WW lipo batteries easily used with Ui2/Di2?

Cheers
Harry

jmX
Posts: 6
Joined: Thu Jul 18, 2013 11:56 pm

by jmX

I think the sprint shifters are simply switches (and they are the only switch like this with etube di2). Since they only plug into the special connector on the new brifters (which isnt the typical Di2 etube connection), I theorize that the brifter does all the canbus logic for that port.

I assume this was due to space limitations for the sprint shifters, and the upside is it gives you an easy way to do RD-Up and RD-Down.

As for decoding the Di2 canbus style communications, I'd be very interested in hearing what people have managed to do.

by Weenie


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

by nickl

drmutley wrote:Hi all,
An Aussie fella seems to have made an A/D converter to allow cateye sprint shifters with Ui2, but unfortunately he won't shed any light on it (he's probably keen on making a quid out of it which fair enough I guess).


He's selling them now: http://www.ebay.com.au/itm/DI2-sprint-a ... a98&_uhb=1

theStig
Posts: 169
Joined: Mon Aug 06, 2007 1:22 am

by theStig

I've thought about this.. a few ideas

1. BT transmitter so RAW di2 signals can be displayed / logged on your smartphone
2. BT transmitter works with GPS on smartphone and maybe a cadence sensor.. once it knows speed and sensor, add some fuzzy logic and Di2 AUTOMATIC TRANSMISSION..

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

by freeloader

it would be interesting if the Canbus/e-tube based system can be programmed to do single-lever shifting. With that, the other lever would just be for braking.

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

by drmutley

Ouch!!! I can see now why he wasn't giving any info away! $250!!! Lol

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

by dale79

freeloader wrote:it would be interesting if the Canbus/e-tube based system can be programmed to do single-lever shifting. With that, the other lever would just be for braking.


I haven't looked at doing that.. you do need 4 buttons to use the system correctly tho, I cant see it being a problem to add remote buttons for the front mech tho but I couldn't really see the point for 90% of riders. I do have a mate that only has full use of one arm and very limited use of the other so ill ask him if he wants to try the extra buttons for the front mech..

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

by dale79

drmutley wrote:Ouch!!! I can see now why he wasn't giving any info away! $250!!! Lol


as I said to you on the other forum. this cost me a lot of time and money to get working and I make $50 per unit.. I sold them to the members of the other forum for $225.. so $25 for what takes me 2 hours to join all the buttons up, heat shrink and seal all the connections etc.. if I could mass produce them then sure the price could come down a lot but would you go and spend $10k on getting the chinese to make the boards, program the chip and cable it all up for you and then they would just rip it off and sell it for them self..

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

by dale79

ps if anyone wants one let me know and ill sort you out

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

by freeloader

Theoretically, i think it's possible to program the firmware to shift the RD and FD accordingly with 1 shifter, without any modification to the hardware.

Unlikely that vendors (Di2, EPS) would provide that functionality, since a electronic shifter would cost more than a brake lever...

To hack the firmware, requires some reverse engineering i guess :)

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

by dale79

ive never looked at front shifting so I cant comment, BUT plugging the climb buttons into the left shifter still shifts the rear mech.. so I will have to figure out the signals required for the front and then write a new chip to do it..

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

by teufelhunden222

If I had a sprint shifter to take apart and play with on my O-Scope I could tell you exactly what was done.
[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

To be honest, based on the wiring it just seems to be micro switches. All you would have to do is put the leads into the end of the connector and see what pressing the button does. It basically just mirrors what the norm shifter does. This does not seem to be that complicated. just adding switches in parallel. I know of a bike shop here that did this a while ago and that is all they did. No big secret. If your ebay seller person is making it seem hard... part of a sales pitch I guess.
[img]<iframe%20height='160'%20width='300'%20frameborder='0'%20allowtransparency='true'%20scrolling='no'%20src='http://app.strava.com/athletes/1677950/activity-summary/ddf436fc1ca509b20d4637cfa80c928da771d2c6'></iframe>[/img]

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

by dale79

ok go try it and see if it works :) cause it does not work on ultegra.. Dura ace yes it works..

by Weenie


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

by teufelhunden222

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.
[img]<iframe%20height='160'%20width='300'%20frameborder='0'%20allowtransparency='true'%20scrolling='no'%20src='http://app.strava.com/athletes/1677950/activity-summary/ddf436fc1ca509b20d4637cfa80c928da771d2c6'></iframe>[/img]

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