First of all I should mention that this was done in 2007 and unfortunately I did not document the things that I have done properly, so there will be a lot of writing. At least there is video of the working system at the end.
Secondly here is a brief explanation the vehicle: It was a blue 2005 Citroen C3 1.4i sensodrive. Among this definition the only important factor for this project is the "sensodrive" function. This means that the vehicle has a kind of automatic transmission. However it is different than regular automatic transmission.
Now I'll just give some information on kinds of transmissions. If you know these or you don't care about them, simply skip the next 3 paragraphs :)
Cars with manual transmission have a clutch pedal to separate the power of the engine from the wheels. One can change the gear only by manually pushing the clutch pedal.
Where as in a regular automatic transmission, instead of the clutch system there is a torque converter which probably somehow converts torque. As you can see I don't know much about how it works, the only thing I know is that it uses transmission fluid and pressure to connect and separate the engine power and wheels. When compared to the manual transmission this is much more complex. In this case driver does not do anything to change the gears, the whole operation is handled by the car's electronics. The gear knob in these cars have P (park-which physically puts a solid gear in the transmission to block it), R (reverse), N (neutral) and D (drive). Because the so called torque converter does not separate the power completely, when you put it to Drive, even before you hit the accelerator the car tends to roll so you have to push brake to stop it.
Finally my kind: Sensodrive (semi-automatic). The mechanical system of this kind very similar to manual transmission. There is no clutch pedal to operate but there is a clutch that is controlled by the electronics. Many car companies have a similar system (Peugeot: Auto6R, Volkswagen: DSG, Renault: EDC, Opel: Easytronic...). The system is being updated regularly but the main draw back is the shaky gear changes. In these cars usually there is no Park gear and they don't move by themselves when you put it to Drive (except for DSG: it imitates the regular automatic transmission electronically).
As long as my project is concerned, the only important criteria is that the gear knobs on manual and automatic transmissions have physical connections with the transmission but semi-automatic ones does not. So their gear knobs are only a set of switches to give proper commands to the electronics.
This is where I enter :)
Citroen's gear knob had N, R, (+) and (-). You had to put it to Neutral to start, and (+) to put it to drive. While driving if you hit (+) it would change to manual mode and you take control of the gears. To put it back to automatic there was a separate Auto button.
One day I was disassembling the car to see if I can modify something (yes, this is regular activity for me) and I realized that the gear knob had a 5 pin input. Since it had only 4 functions I assumed that there was a switch for each function and a common ground connector.
Initially I hesitated to open up the gear knob box because Citroen guys did not want it to be opened so they used rivets. One weekend my wife was on a business trip (this is important because rightfully she was against this operation due to the not so small probability of messing up our only car) and just as a coincidence I was alone in the house with the gear knob. By the help of an electric drill I cut the rivets off and there it was:
This is my control card to imitate the gear switch and operate power windows |
My first idea for gear buttons |
Repaired and modified MINI Cooper switches |
Other than the gears I connected the window buttons and auto-shift switch to the respective buttons and it was all done. The beauty about it was that the auto button also had a light on it, indicating if its in auto mode or not, so I connected it to the former switch of fog light which had a light on the tip of the switch.
Final look of the middle console |
Here is the video of the working system. You can hear the gears changing as I push the buttons.
Work in progress concole |
At this stage, before I had a chance to construct the final middle console from fiberglass, we had the great news that our second son is on the way. Since we could hardly fit C3's boot with a single baby, we decided to upgrade to a C4 Grand Picasso.
During this modification I was very careful not to do anything irreversible, I just put the original parts of the car back and sold it. Of course it was touching to let go of a vehicle after spending long hours in it but the excitement of the brand new car was overwhelming.
I drove the car like this for about a year with no problems. I don't know how the idea first got into my mind but I ended up spending days or even weeks on it. It was only as practical as its original but much more cooler. I had great fun with the valet parking as well. The valets always remembered me when I got back :)
Thanks for your patience..
The next entry will be a useful one: Repairing a Renault Card Key that does not start the car.