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Discussion Starter #1
Hi Guys
I have been busy with other projects, but have managed to do some testing of the MIMA_C in my car. (no test pilot volunteer yet)
As soon as the MAP , TPS, and Battery amps signals were all connected to the MIMA board, I began to have unreliable A/D conversions and could see with the scope that the problem was due to high frequency noise spikes between the individual module grounds. The signals all need to be read by the MIMA A/D converter, so they needed to be brought to a common ground in the MIMA . Several simple ferrite bead and differential input schemes were tried, but none truly isolated the signals, or removed the noise. I finally decided to go all the way, and have designed a full precision optically isolated input for the three signals that should solve this problem, and let me get back to the software and final board layout issues.

http://pages.cthome.net/genesisone/index.htm

Thanks for your patience.



:wink:
 

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Mike,

sorry to hear about the roadblock you ran into! But it seems to me you are on the right track to overcome it, already!

I remember when we first talked about it that there are various signals referenced to different grounds. Optical isolation is the surest way to resolve the problem. I don't think filtering will get you there, since what you see are most likely ground-loop currents. Isolation is the only thing that will stop them for sure!

I'm sorry I don't have more time to contribute to the project. I think you are doing a great service to the Insight comnmunity!

Thanks for all your work and keep it up!
 

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Discussion Starter #3
Good news!
The Opto couplers did the trick. I now get clean stable signals on all analog inputs.
I will put some scope traces before and after and photos of the prototype board @
http://pages.cthome.net/genesisone/index.htm
Now I can proceed with board layout, parts purchacing, and throttle based control software. :lol: :wink:
 

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Discussion Starter #4
Further update
To help with the throttle based control, I have made up a test conector that lets me connect the Micro in the MIMA_C with a Labview based Data Acquisition card in my notebook computer. I am capturing the ThrottlePosition, MAP, Joystick,Battery amps, CMDPWR, and both MAMODE 1 and 2 signals in real time on a graph while driving.(don't need a test pilot) The data is stored to an excel spreadsheet file that I can view later in detail with labview. I will do some test runs tomorrow, and post some of the graphs on my web site. It should help me define normal IMA action and MIMA based action, of all my signals, and therefor be a great tool for determining the best approach for the throttle control. It will also let you guys see the interactions of the signals.
 

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I like your testing approach! This will give us some really solid data to work with. I'm really impressed with the circuitry for the opto couplers as well. :D :D :D

Kip
 

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Discussion Starter #9
Hi Guys
I have built up the first MIMA_C board.
I could not help reflecting on how much building the board was like building a heathkit, and really think that some of you will want to build it your self.
The ground plane, and small pads will make good soldering skills and a clean very fine tipped soldering iron a must for building the board.
It took me well over 2 hours to build the first one, and the price of the assembled and tested board will need to reflect that, which is another reason to offer you the option of building your own. I will build up the other boards, and see how fast I can build them with the experience of several boards under my belt.
http://pages.cthome.net/genesisone/index.htm

This is an exciting time.
:lol: :wink:
 

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Why is the display necessary? Perhaps I am confused on how the MIMA has been designed, would the existing assist/charge guage not function normally?
 

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Mike, it looks like Scott did a fine job of the layoout and the etching looks great. Plated holes? Heathkits never looked so good! 8)
 

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Discussion Starter #13
Kip
Heath kits had boards that were a little less densly populated, and usually did not have flooded ground planes, which make the sharp soldering iron tip a requirement. I will also need to make up some assembly instructions, and it will be hard to match the heathkit manuals, but that sense of satisfaction when it is all built is the same as with Heathkits.
The testing of the built boards prior to installing in the car is the only part that concerns me. One way to do it, would be for the MIMAkit builders to send the built boards back to me to test, calibrate, and install the micro with the latest software, then I send it back to you????
Ideas?
I had originally thought of providing a MIMA test board with pulse generators and the other signals to fully test the board, as part of the kit version, but that would increase the cost, and be more stuff to build, so at this time, I am not planing to offer the test calibration board. I will use a scope, and several signal generators to do my board testing, and possibily use a LAbview based test system that will print out a test report for each finished board.

Foxpaw
The display has several functions.
1. The assist/charge display in the car is not really telling us what is happening. It can show full assist at 50amps, while mima is feeding 100A to the motor, and more importantly it can show only a background charge (4 bars)while we are charging at 50A. It can show no background charge when the charge is still happening.
The MIMA display is accurately telling us what the actual current detector is seeing. It is the same signal that the car uses to compute SOC, so in theory we could generate our own SOC determination with it.
2. The display gives feedback as to what calibration or operational mode we are in, so it is very important to the normal operation of the present MIMA_C operating system.

I have not yet set up MIMA_C to operate in the MIMA light mode, where it will sense what features are connected, and be operational with only the basic joystick functions.
For this first 7 units, I will want people that are wanting the fully functioning system with joystick, display, MPI and battery temperature monitoring and fan controls, the MAP, VSS, and Throttle signals as well.
Kevin
The thought with the tiny surface mount display was to make a small display, with a flat back that could be mounted with double stick tape right on the present dash display under the present assist charge bargraph, on top of the shift lever, on the steering wheel with the joystick, or some other place I have not even thought of.
The light detector could be sensing the present LCD display brightness, and adjust the led brightness to be compatible with the LCD brightness, and be a separate board along with the PWM brightness control transistor.

A look at the display schematic, and one can see that it is very simple electrically, with the only requirement that the same connector pinout is used. The leds can be any size or any color, with the only requirement being that the current through each led when connected across 5V will be limited to 15 MA each LED by the selection of the proper voltage dropping resistor.
The surface mount leds are a bear to work with, as they are about half the size of a grain of rice, don't sneeze, or you will loose them, and the soldering will need to be done under a microscope, with tweezers.
I will make up a prototype, but to not want to divert energy from getting the first 7 units built and installed, I will put that on hold along with the eventual design of a wireless joystick and switch board that would allow steering wheel mounting of the joystick and switches.
:wink:
 

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Mike wrote:

One way to do it, would be for the MIMAkit builders to send the built boards back to me to test, calibrate, and install the micro with the latest software, then I send it back to you????
I will use a scope, and several signal generators to do my board testing....
BRAVO :D

You hit the nail squarely on the head there Mike.
That's the box I will check on the order page :!: :!: :!:
(Since I'm too far away to be one of the Magnificent Seven :cry:)
 

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Discussion Starter #15
Great
Thats how we will do it. The kit builders will get the parts and boards, build the boards, and if they feel confident, test and tune their own MIMA_C.
If they want me to test the boards and install the latest firmware, they can send them back after construction, and I will get them running with the latest operating system. Assuming that you haven't destroyed the board with your soldering.
If you want software updates, you can ship back your old processor for re programming(can be redone thousands of times), have me send you a new one with the program burned in.
Any further updates after that , You send me the old one whenever you want to upgrade.
If you can connect with me, I can upgrade your cars system right in any parking lot, in a few minutes.

:wink:

[moderator insert so as not to bump the thread up the line un-necessairly]

For those interested in the MIMA project or those still wondering what it is the threads have become too fragmented for the developer to maintain and he has requested that his other MIMA threads be locked.

Please understand that any further suggestions for design changes will not be honored since the process is too far along. However, since its *opertation* can be easily modded in software such limited opinions will be welcome.

A few of the old threads that will most likely answer all your questions are here:

Hybrid controls and the MIMA project
http://www.insightcentral.net/forum/vie ... php?t=2471

Mima Statue Update
http://www.insightcentral.net/forum/vie ... php?t=3176

MIMA L works in a CVT (automatic circuitry with foot pedal)
http://www.insightcentral.net/forum/vie ... php?t=3233
(Moderators note: the newest version of MIMA is CVT compatable)

MIMA Display and Joystick Housings
http://www.insightcentral.net/forum/vie ... php?t=3353

The developers site is here:

http://pages.cthome.net/genesisone/index.htm

Its a complex topic and modification. And one that should be carefully reviewed if your deciding on purchase. The purchase thread is here:

http://www.insightcentral.net/forum/vie ... 9&start=15


The subject is still open for discussion at the developers selected for consolidation thread here:

http://www.insightcentral.net/forum/vie ... php?t=3357

Locking other threads. Future MIMA threads will be locked and follow-up's directed to the thread above.
 

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how about you send out an updated eprom, we install and verify operation, and send back the old one? that way we dont lose MIMA for a couple of weeks waiting for snail-mail.

btw: cant wait to get one of these!

andy g.
 

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cool! i have one at home, and maybe access to one at work. what chip are you using?

andy g.
 

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Well Insight 00 #4738 has MIMA-C Ser #001 installed. I drove up to CT and Mike guided me through the install. It was a lot of fun looking around in the battery compartment. We spent about a day and a half but a lot of the time was spent looking at a lot of Mikes other projects. He has a few more installs lined up and the others will probably be faster unless they do what I did (Mike whats that?). I think there are about 40 wire taps needed and by the end I was felling pretty confident in the sodering of the connections. Mike built my circuit board (actually he tested it for a week or so in his car) but with detailed instructions I think a novice could handle the install. The key would be to go slow and double check everything. (I had a few mistakes in the process like putting the diodes backwards, cutting the wrong wire etc) but Mike caught them as we checked the wiring). I think when the instructions are complete it will be step by step and thus if you go slow and are careful you will be able to do it. Mike is also planning to have several installation levels that will allow you to tackle the project in smaller chunks to build your confidence as well.

First Impressions:

1. Wow! Being able to tap the IMA for full assist or regen is pretty impressive. Reminds me of the time I drove Willie's little Red Rocket and felt the turbo kick in. It definitely adds to the fun to drive factor. I used full regen on several hills instead of the brakes and it does a pretty good stopping job. The assist or regen response is imediate with no delay or lag. This mode of operation is called the Auto-activate Mode. It allows temporary manual joystick control of Assist/Regeneration. This mode is activated by moving the joystick. After three seconds with no joystick activity (joystick back in the center), the system reverts back to standard Insight IMA mode, with background charging if needed. You can think of it as the manual override to the IMA logic. It allows you to do stuff like get full assist from the electric side even though you are not pressing the gas at all. In other words you are crusing along at 150 mpg in 5th gear and want to pass a car. No need to change the throttle position or downshift. Just hit the joystick and stay at 150 mpg and let the electric side provide the needed extra power. I think this is the mode I will use the most but only time will tell.

2. The next mode is Active MIMA Mode. Its esentially the same as the above allowing joystick control but the car does not return to the Insight IMA mode until you disable the Active MIMA mode using a push button switch. I can see using this mode when you don't want the parasitic background charging. I havn't really spent much time with this mode but intend to get some experience with it in the future.

3. The next mode is called MIMAAUTO Mode. Its kind of like an electric cruise control based upon the MAP signal. Basically if the mpg reading falls below a threshold that you set the IMA kicks in to meet the demad instead of the engine. If the MAP signal goes above the point that you set then the Regen kicks in to charge the battery. Its amazing to see what this can do for fuel economy. Mike and I went out on a test run and got 120+ mpg for over 10 miles but note that we had too high of an assist point so the battery was not staying completely charged. I plan to experiment with various set points but so far have only used the really high ones. This really has a lot of potential when working with a cruise control. I have a Roseta cuise control and when both it and MIMAAUTO are on they complement each other beautifully. For instance when the car slows to the min speed set on the cruise control the cruise control will increase the throttle position causing the vacuum to drop. Normally this would continue until the engine provided enough power to maintain the speed set. However with MIMA-C the dropping vacuum triggers MIMA which reacts much quicker than the engine and causes the IMA to start providing the additional power needed to maintain speed. As the speed increases the cruise control reduces throttle pressure causing the vacuum to increase thus dropping the need for assist. In other words this is a cruise control that combines both the speed and mpg set points!!!!!! :D (First time I ever tried one of those smile faces.

4. But wait there's more! Mike has a display that shows you the real current values flowing too and from the IMA. I think Honda used a random number generator on the assist and regen guages as they don't show things correctly. Mike uses 4 leds each representing a threshold of amperage. So you can get 1-4 green leds representing 12.5 amps each of assist or 1-4 red leds representing 25 amps of charging each.

5. He is a user of the system and is constantly trying to improve the controls and programing. As a early installation I have no worries about my system becoming obsolete because I can simply email Mike and tell him to send me the chip with the latest program and then my system will have the latest updates.

6. Mike is pursueing a lot of possibilities for our cars and I hope he does well with the sale of this system. Take a look at http://www.edrivesystems.com/. This is a plug in Prius option for around 10K. With MIMA-C and a home charging option I could see the Insight getting incredible mpg on commutes by using higher set points in the AutoMIMA mode and then get charged later or shift to auto-activate mode to let the engine do more charging. Mike is also looking at a more powerful battery install which would give us all more options when our OEM battery needs replacement and we are well beyond the 80K waranty.

7. Believe it or not I actually was speeding most of the way back to DC. Part of it was having fun with Auto-Activate mode and the other because I lost the fuse to my stereo amp and was getting tired and did not have my usual way of staying alert. Even at 70-75 mph I was getting segments near 100 mpg with MIMAAUTO mode. I would then shift to Auto-activate until I got the battery charged back up. I'll provide more mpg info once I get more testing on a route that I know the result ranges without MIMA.

Notes to Mike:

1. Is there a reason for the 3 sec delay in MIMA autoactivate mode between the no activity on the joystick and return to normal Insight IMA control? I found that sometimes I would use the joystick to slow but then if I tap the brakes I get no regen until the IMA logic takes back over after the 3 sec delay). If this was arbitrary then perhaps cut it to return as soon as the joystick returns to center. Can't see anyone letting go of the joystick and then needing it again in less than 3 seconds but perhaps others will have different feedback.

2. I am still getting used to the interface. I think I hit it sometimes unintentionally. Perhaps I should have used the trigger mount that you use but that is easy enough for me to change later. Anyway I had two times when the car did not start from autostop (I think it was because I bumped the joystick but will test some more). The first time I restarted with the key and the second I just used the joystick and the engine came to life. (I am guessing the 3 seconds also was the root of this but havn't tested the theory). (I assume the manual override of bumping the joystick disables autostart until the Insight IMA logic takes back over).

3. You were right on the new Prius using less modules and lower voltage battery. It uses a transformer to step the voltage up to 500V and the new batteries have a 35% increase in power density which give it the 2 sec faster 0-60 time.
 
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