DIY MIMA L
|Soon after Yves and I got MIMA to work, I built MIMA L, which I used for several months. MIMA L allows manual control of the IMA, or defaults back to stock operation.I put up a schematic of this simplest MIMA circuit for all that wanted to build their own MIMA.|
MIMA L PDF
The photo is my first MIMA, which I used for several months.
This page will showcase some of their systems.
If you have built your own MIMA system, and would like to be included on this page, just let me know, and send me some photos.
|Mikes breadboard MIMA L|
|JoeCVT main board|
As a forum member at insightcentral.net, I was very interested in the MIMA project from the very beginning when Mike and Yves first tapped into the wiring harness and discovered manual control of the IMA. Shortly afterwards, Mike designed a circuit (MIMA_L) and made it available to the public with all of the parts needed to build your own MIMA. I do not have the electronics background to design a circuit like this but I did want to try to build my own MIMA. I ordered all of the same parts that Mike had in his circuit and while waiting for them to come in, I created diagrams of how I would layout the parts on the board. I wanted to make the smallest board possible and solder traces onto a small plain board that I got from Radio Shack. My soldering skills are not so impressive but here is what the front and back of the board looks like:
|Joecvt MIMA L board|
I wanted to include some auto fuses and a switch to turn the whole circuit off if I ever needed to. Here are some pictures that show the installation area with connections complete and the actual size of the board when compared to the Insight car key and remote.
You may have noticed from the gear shift console that I have the CVT model Insight. The CVT does a pretty decent job of keeping the battery charged so I was mainly interested in the assist portion of MIMA. Also, I wanted to keep the look of the car as stock as possible so I mounted a pedal near the area where the clutch pedal would be for the manual transmission. This pedal replaces the normal MIMA joystick function for assist and allows for hands free usage (while giving my left foot something to do :) The pedal is the type that you would find in arcades for auto racing (the "gas" pedal). As you can see from looking at the photos below, the pedal is pretty much hidden when looking downward (left photo) until you start looking more under the dash (right photo) Notice how high the MIMA pedal is compared to the left foot rest.
The pedal serves more than just the assist level. I wanted this setup to be like an auto switching MIMA mode so I included some extra circuits on the MIMA board that will supply power to Mike's design when the pedal is slightly depressed. Basically when the pedal is not used, the car drives like normal IMA. Upon pedal pressure, MIMA_L is powered up, takes over control and assist corresponds with pedal pressure.
One of the problems I had while adjusting the sensitivity of assist was the inconsistent voltage of the Insight. When the Insight does not have much 12v power demand (no headlights or high speed blower fan). The voltage fluctuates from something like 11.8 to 12.3 volts. Unlike Mike's design, the voltage going to the pot in the pedal came directly from the Insight since the MIMA circuit does not have power until the pedal is engaged. This was messing up my assist level during voltage fluctuation. The fluctuation could be corrected simply by turning on the parking lights to provide much more consistent power. I did not want to have to do that all of the time so I went to Radio Shack and bought a cigarette lighter adapter that steps the voltage down from 12v to 9v. The 9v was very consistent and the circuitry was so small that I was able to piggy back it onto my MIMA board so problem solved. I took these photos awhile back when I first installed MIMA so I don't have a photo of the adapter but you can imagine how small it is since it originally was designed to fit into the cigarette lighter socket (like the cell phone adapters).
I mostly use MIMA for very slight inclines and try to use only about 4 bars of assist. I have found that by using 4 bars, I can go for a long time without much drain on the battery. On my 22 mile trip to work, I could usually get about 4 mpg more by using MIMA at strategic locations during my travel. Although the CVT does a pretty good job at keeping the battery charged, it does sometimes pick some bad times to do so. I may add another circuit to disengage assist and regen when not needed in a few more months.
There is another use that I just discovered recently. If your tires start spinning in the snow when starting out, just use MIMA as your acceleration and you can get out much easier. Unlike the manual transmission, you can't just shift into a higher gear to reduce wheel spin with the CVT...Sort of like MIMA traction control...
It is also just fun to show your friends that you can drive around the block without using the gas pedal :)
Thanks Mike for the MIMA design and your continued efforts to improve the Insight driving experience.
JoeCVT - Just your average CVT owner
MIMA Insight System:
|Nemystic MIMA # 018|
Cousin Brian who won the 2005 Tour de Sol using his home built MIMA L, ran with the system for nearly a year.While Brian continued to get great MPG with MIMA L,
PIMA, Joylock, the LED Display, Battery temp control, and ABC functions that the full MIMA system provide, finally convinced Brian to upgrade.
|Brian's MIMA L with wiper stalk Joystick mount|