Carputer + ECU + G forces = ?

**Danzzigger** · 10-03-2007, 08:02 AM

Hey guys I've got a r31 skyline at the moment, but I'll be wanting to transfer the carputer over to a hr31 when I get the funds and I get off my P's. Anyway, the car is a 1988 model so I'm not sure what OBD it has, or if it even has one :S.

Now what I was wanting to do is have an aftermarket ECU hooked up to the carputer for instant access to things such as rpm, hp etc.... but the main thing that I'm after (here comes the hard part) is also G forces. So I can see what kind of G's I'm pulling around corners. I've looked at a few aftermarket ECU's and all I can find is the APEXI G-sensor, or I've heard that Motech has G force acceleration graphs like I'm wanting. Now I'm gonna be on a budget (as you can see with a r31 skyline :P) so I want to see if there is a cheap solution to get a carputer with the G forces integrated rather than having a external unit such as the APEXI G-sensor as the motech costs 8k apparently!

I was talking to my mate about it and he said motech most likely figures out G forces by means of mathematical equations, is this true? If so, would it be hard to implement a mathematical equation into a different aftermarket ECU which is cheaper? :P

Cheers
~Danz

**shotgunefx** · 10-03-2007, 09:03 AM

accelerometer's can be had for cheap, so if it going to the CPU instead of the ECU is ok, I'd look into finding one with a range and accuracy that meets your needs.

Here's one place that sells some
http://www.sparkfun.com/commerce/cat...hp?cPath=23_80

update

This page lists some ranges for typical, sports and F1 cars to give you an idea of the sensor range you would need. (A hard crash is bound to peg any sensor you get). So I guess the biggest factor would be sample time.

Automotive Acceleration (g)
event typical car, sports car, F-1 race car, large truck
starting 0.3 - 0.5, > 0.9, 1.7, < 0.2
braking 0.8 - 1.0, > 1.3, 2, ~ 0.6
cornering 0.6 - 1.0, > 2.5, 3, ??

**Danzzigger** · 10-04-2007, 02:28 AM

wow cool as, ok so to view these 'Accelerometers' on the PC, what kinda software would I require? I'm a total n00b to all of this so all the jiberish wording they use makes no sense to me. I would most likely go for a predone unit, am I spossed to aim at a G force max limit as close to the application as possible for a better reading?

At this point in time my car isn't going to be that fantastic, I just want to have this kinda stuff open for the future. Would my car have OBD1? how would I access it? or is the only solution to access my rpm, speed etc through a aftermarket ECU?
I want to if I can keep all the info in one program, but if I'm running an aftermarket ECU and that Accelerometer through the PC, obviously you are going to need some kind of custom 'front end' to incorporate it all. Is it possible to do it some other way?

I'd rather spend the extra money to make it universal however since I believe the hr31 and the r31 ECU's are different, and therefor I'm guessing the OBD1 is different (if it has one).

So yeah, thanks for the link, its great to see that theres such a easy solution (well it looks easy, but looks can be deceiving :P). Does anyone have any other solutions? Like perhaps a aftermarket ecu with some kinda of input which can incorporate an additional sensor. I don't know too much about aftermarket ECU's aswell to be honest, i thought they all had extra inputs so that u can add features. Or perhaps just adding a software side to the ECU which calculates the G forces by mathematical means.

thanks for the input shotgunefx
~Danz

**Danzzigger** · 10-08-2007, 08:07 PM

Anyone else with some ideas?

**galvitron** · 10-09-2007, 02:17 AM

Originally Posted by shotgunefx

This page lists some ranges for typical, sports and F1 cars to give you an idea of the sensor range you would need. (A hard crash is bound to peg any sensor you get). So I guess the biggest factor would be sample time.

Automotive Acceleration (g)
event typical car, sports car, F-1 race car, large truck
starting 0.3 - 0.5, > 0.9, 1.7, < 0.2
braking 0.8 - 1.0, > 1.3, 2, ~ 0.6
cornering 0.6 - 1.0, > 2.5, 3, ??

I can say for certain that those g-force examples are suspect. F-1 cars can pull 5 Gs on cornering and 4 on braking. Just watch the G-sensor on the in-car shots during an F-1 broadcast. They are broadcast on the world feed so it doesn't matter what channel you watch.

Sorry, I'm a rabid F-1 fan and I don't like my fav cars being underrated

**2k1Toaster** · 10-09-2007, 02:36 AM

Originally Posted by Danzzigger

wow cool as, ok so to view these 'Accelerometers' on the PC, what kinda software would I require? I'm a total n00b to all of this so all the jiberish wording they use makes no sense to me. I would most likely go for a predone unit, am I spossed to aim at a G force max limit as close to the application as possible for a better reading?

At this point in time my car isn't going to be that fantastic, I just want to have this kinda stuff open for the future. Would my car have OBD1? how would I access it? or is the only solution to access my rpm, speed etc through a aftermarket ECU?
I want to if I can keep all the info in one program, but if I'm running an aftermarket ECU and that Accelerometer through the PC, obviously you are going to need some kind of custom 'front end' to incorporate it all. Is it possible to do it some other way?

I'd rather spend the extra money to make it universal however since I believe the hr31 and the r31 ECU's are different, and therefor I'm guessing the OBD1 is different (if it has one).

So yeah, thanks for the link, its great to see that theres such a easy solution (well it looks easy, but looks can be deceiving :P). Does anyone have any other solutions? Like perhaps a aftermarket ecu with some kinda of input which can incorporate an additional sensor. I don't know too much about aftermarket ECU's aswell to be honest, i thought they all had extra inputs so that u can add features. Or perhaps just adding a software side to the ECU which calculates the G forces by mathematical means.

thanks for the input shotgunefx
~Danz

Originally Posted by galvitron

I can say for certain that those g-force examples are suspect. F-1 cars can pull 5 Gs on cornering and 4 on braking. Just watch the G-sensor on the in-car shots during an F-1 broadcast. They are broadcast on the world feed so it doesn't matter what channel you watch.

Sorry, I'm a rabid F-1 fan and I don't like my fav cars being underrated

Lateral G's are completely different. Those speeds are the forces when accelerating in the direction of the track. The g's you mention are the g's that try to pull the driver to keep going that way, but instead are now turning, completely different, and yes 5gs is reasonable for that if going blazingly fast!

Anyways, as for software, and hardware, The Fusion Brain that we sell does just this. We had a slight manufacturing problem with our version 1 accelerometers, but the next version is due in about 2 weeks, and can measure up to 6Gs on each axis (3-axis). The software is free and customizable, and the hardware is cheap, and through USB and runs directly off the car battery. So it is a plug and chug sort of solution.

**shotgunefx** · 10-09-2007, 08:23 AM

Originally Posted by Danzzigger

wow cool as, ok so to view these 'Accelerometers' on the PC, what kinda software would I require? I'm a total n00b to all of this so all the jiberish wording they use makes no sense to me. I would most likely go for a predone unit, am I spossed to aim at a G force max limit as close to the application as possible for a better reading?

At this point in time my car isn't going to be that fantastic, I just want to have this kinda stuff open for the future. Would my car have OBD1? how would I access it? or is the only solution to access my rpm, speed etc through a aftermarket ECU?
I want to if I can keep all the info in one program, but if I'm running an aftermarket ECU and that Accelerometer through the PC, obviously you are going to need some kind of custom 'front end' to incorporate it all. Is it possible to do it some other way?

I'd rather spend the extra money to make it universal however since I believe the hr31 and the r31 ECU's are different, and therefor I'm guessing the OBD1 is different (if it has one).

So yeah, thanks for the link, its great to see that theres such a easy solution (well it looks easy, but looks can be deceiving :P). Does anyone have any other solutions? Like perhaps a aftermarket ecu with some kinda of input which can incorporate an additional sensor. I don't know too much about aftermarket ECU's aswell to be honest, i thought they all had extra inputs so that u can add features. Or perhaps just adding a software side to the ECU which calculates the G forces by mathematical means.

thanks for the input shotgunefx
~Danz

Hey, sorry, been away for a few.. If you got one of those serial ones (like the one with the port all wired up), writing serial comm software isn't usually too hard, but then again, you have to write software. So depending on your aptitude in that department, what constitutes difficult is going to vary. Also depends on what you are trying to integrate it into. (ie what software for all the other ECU input).

Probably more work than you would want to do, but probably a good deal less difficult than a custom ECU. The first thing I'd do is find out what type of OBD is supported. I couldn't find anything definitive while googling. Maybe this site will help?

http://wiki.r31skylineclub.com/index.php

Seeing the Fusion Brain supports accelerometers (didn't know this) and has good software support here, that's probably a good direction to go.

**Danzzigger** · 10-11-2007, 05:39 AM

Yeah, I'm not a wizz with computers yet, not even electronics, but I'm getting there.... I actually try to stay away from most programming, my brain hurts otherwise. I'm signed up to the r31 forum, I talked to a mate the other day and he said r31's don't have OBD, so I'd be starting from scratch really.

Looking at the brain fusion, it offers 3 axis G Forces, does that mean, x / y / z dimensions? so like up down, left right, and fowards backwards?
I heard that it can be configured with any frontend, so thats good news.... Although it would involve programing, which for me is bad news :P.

When I was talking about an aftermarket ECU, I wasn't meaning a custom hardware unit, I was more so referring to if its possible to integrate 'extra' programing, like a math equation which figures out the G forces, or if you could simply add the sensor into one of the free analog inputs.

Pretty much I'm after this setup:

Gps
music
car monitoring (rpm, etc....) <---- not essential atm as my car is pretty crap performance wise.
amount of G's around corners
perhaps Air con
and other stuff that I can't think of atm :P
But I want it all to end up into 1 complete software / frontend, such as the r34 gtr. How difficult would it be for me to learn / do the programming in order to produce such a product? I'm willing to take a few headache tablets and put my head into it, and try and produce a awesome end product.

By the looks of it the brain fusion is the way to go, I live in Aus though, so I'll need to make sure I get all the hardware required for my setup. So I'll have to wait till you have those accelerometer's in stock.

Cool as, thanks for your input pplz.
~Danz

**2k1Toaster** · 10-11-2007, 01:57 PM

Originally Posted by Danzzigger

Looking at the brain fusion, it offers 3 axis G Forces, does that mean, x / y / z dimensions? so like up down, left right, and fowards backwards?

yes. That is exactly what that means. And they can all be read at the same time.

Originally Posted by Danzzigger

I heard that it can be configured with any frontend, so thats good news.... Although it would involve programing, which for me is bad news :P.

No programming required. There is a skin designer utility I have/still am creating that is all GUI based. Click what you want, enter the settings from the menus, and it appears on a mock skin. Click and drag it around the skin to wherever you want it to be. Save and your done. It is quite simple.

Originally Posted by Danzzigger

By the looks of it the brain fusion is the way to go, I live in Aus though, so I'll need to make sure I get all the hardware required for my setup. So I'll have to wait till you have those accelerometer's in stock.

Cool as, thanks for your input pplz.
~Danz

We will be sending out a mass email once they arrive in stock, so if you are signed up as a customer who receives newsletters, then you will be notified once they are in stock.

Cant wait to see how this turns out! Takes lots of pictures of your install! We like pictures!