Attempt at cheap homemade version of Harmony

[Normand_Nadon]

Wow! You did go into a lot more efforts than I did for the electronic shift interface!!!

I simply used an RC sailboat servo that is SLOOOOOOOOW and geared down to a super torque ratio... Also, it is "endless"... meaning there is no stopping pin inside.
I ripped all the feedback circuitry from the inside and plugged the small motor directly to the 3 pos. switch in the handlebars.
The setup is powered by a single 1350mAh LiPo cell salvaged from a dead pack. It lasts for more than 500km before becoming a little to weak to shift well.
I will probably change the cell this year as I think I had it over-drained and it seems dead.
Fully charged, it will easily shift under "regular" load but I need to ease a bit on the pedals in super steep climbs.

Here are some pictures .. The pulley came with the servo, I simply had to drill 2 small holes for the cables to go through...