DIY DI2

[Ypsylon]

Yeah, there's this one strange bloke claiming that, after adjusting, he runs di2 on his MTB without the front wire harness and therefore without the "brain", on WWs.

I think he calls himself madcow, or sumpn.

I, for one, am confused. But I was confused before I read this thread, too, so I may not count.

[manninen]

Sorry, that's not the case. I used a logic analyzer and reverse engineered it. The position pin is just used to auto trim the front and when adjusting the RD.

The RD takes one pin in that does both up shift and down shift depending on the waveform.

ok, might be just easier to buy handlebar cable set

uh... today i´m starting to wiring up my frame

ypsylon: waiting to madcow saying me something to this thread, he is involved with fairwheelbikes.com

[skimons]

ok, might be just easier to buy handlebar cable set

that is for sure. still, if you want to save (some) costs, you can buy separate cables (actualy, just 2, the RD cable and the 5-pole junction cable, although even the latter can be left if you cut up the front wiring harnass anyway) as indicated by me, and a 7.4V battery and connect it with a lot of solder, heat shrinkable tubes and the wiring diagram of jeffr.

then, just buy a Shimano RD and the front cable set, plus a 3-pole shifter and it will work fine.
there you are, for (around) 600 euro's.

[Jeffr]

You could indeed cut up the cable leaving the front wiring harness and splice in the battery and the wires to the RD. That's all you'd need. In front of the front wiring harness you can use any kind of button you like. It needs only to complete a circuit.

I have verified that everything works without a front derailleur or rear junction on a test fixture. This is also easily deduced once you know the signaling protocol. Everything works even without the POS pin connected at all. Although some features are then inoperable.

[manninen]

shimano-nordic couldn´t get me 7E3 98030 rear der cable, i send inquiry to madison ( thanks skimons)
well, it´s not really about money to not buying them all, just a principle to break a rule

[Oilman]

But generating a proper wave form for the RD and FD is very easy since it is a long pulse (for shifting in one direction) and a square wave for shifting in the other direction. The signals are quite slow for today standards, it is all in the milliseconds.

[manninen]

drill it thru inside tube


old phone cable, fishing line and super glue



voila!

next is gonna be RD cables and plan the battery for sure that´s gonna fit inside seatpost (only 27.2mm)

[skimons]

i thought since nokia came up all wired telephones were banned from finland

[manninen]

cable from phone like this


i may could use the number selector as gear shifter as well? bolted to the stem

[manninen]

nothing new here, i´m gonna buy that handebar cable set. maybe flight deck model



waiting to get some parts

[Ypsylon]

I think the phone you showed would look way cooler on your handlebar than the flight deck computer. Just my humble and silly opinion. Do you happen to know if it supports ANT+, btw?

I mean the flight deck.

[manninen]

i don´t think it´s ant+

looks like i´m not gonna get that sc-7900 anyway. front chainring settings between 56-50T and i´m using 48T, ok it only means wrong virtual cadence
but still

uhhhh.... ordered battery from hong kong 30.10-2010. got it today but they sent an wrong battery. it´s 11.1v
i hope they sent an right one without hassle

[Mike K.]

Manninen very clever entry point for the wire.

[manninen]

Manninen very clever entry point for the wire.

threads are still there

i have to drill larger hole to chainstay to get wires out
i might get right 7.4v battery without sending back that 11.1v so i´m gonna tune LED lights to my winterbike

[FAQinc]

When life gives you lemons you make lemonade, when a company from Hong Kong gives you the wrong battery you make LED light tunning