SCCA RX7 RACER

Hi All,

My Mega Squirt is working fine and I can slowly make tuning adjustments from my logged data runs. As all ways we learn as we go. My mechanical skills are very strong but my computer skills are on the weak end of the scale.

I put the question of tuning the car with computers in the method of a wireless system to my daughter and husband. They are very strong in the area of working with all aspects of computers. They said it’s simple to set up a wireless network from a lap top computer in the race car to a lap top set up at track side.

I showed them the communication information in the Mega Squirt print outs. After a quick look at it they asked a few questions that I did not have an answer.

1- They felt that the serial data rate of 9600 is old and slow but could work because very little data at one time will be transferred (Plotting air fuel changes). Has anyone any input about this?

2- Providing that the lap top computers are adequate in speed. Can the timer interval be reduced down to 1 (ms)? Has anyone used this speed with out any problems?

3- They did not understand the lag factor built in to the MS system. Was this to change the rate at which the changes were made to the program? Or is it something to do with the values from the sensor and the Mega Squirt. If we ran 100 in the factors for every thing what effect would it have on any type of information transfer?

Thanks for any help in this area. I may be opening a can of worms.

muythaibxr

They are correct. It is a very slow rate... but sufficient for the use it's being put to.

I've never tried... My suggestion is to try it and see. I would not suggest it though, as you might disrupt serial comms and make it difficult to change settings.

The lag factor is to allow the megasquirt time to do what it needs to while burning to flash... if you make this lag too small, it can affect the reliability of transferring data to the megasquirt, as it won't be waiting long enough for a piece of data to burn to the flash after sending. It will send the next piece of data, and the megasquirt will not respond to it because it's busy burning.

In other words, you can experiment, but changing the defaults is likely to cause problems changing settings.

Another problem will be getting megatune to see the 802.11g connection as a serial port. I don't know if there's any way to do that, but it's necessary since megatune is designed only to use a serial port for communications.

Ken

Aaron Cake

iTrader: (1)

A while ago I ran across some RS232 to IP stacks that could transfer serial communications over any TCP/IP network. That's probably the route you would want to take. Some of these are available at download.com if you search for "serial IP". However in my experience Megatune freaks on anything that isn't a standard serial port (to this day I can't run it on my PCMCIA serial adapter that all other standalones don't have an issue with....) so you might end up with corruption.

muythaibxr

We have some ideas to make the serial comms more reliable in the MS world starting possibly with ms2/extra (and some new tuning software).

Basically we'll be making the comms protocol more robust, with acknowledgement sent back to the PC when a burn is successfully completed (not done right now). This will fix most of the problems I listed in my last post as well...

Ken

West-se

Are you trying to tune the car on the fly while your racing or tune via wireless while in the pits and not need a laptop in the car during tuning ?

If its tuning on the fly while driving not sure what rules are with SCCA with in car tellemetry.

If its just connecting to the MS via wifi not sure if wifi is the answer, but maybe bluetooth rs232 adapter, this would allow you short distance connection. Although in theory it would work not sure how well it would work in the real world since, I am not sure if there is any type of error handling within the communications portion of the code.

SCCA RX7 RACER

My plan is to install a new lap top in the car so that a lap top track side can work the Mega Squirt in the area of air fuel ratios adjustments on the fly during practices. Yes during qualifying and races I can not use it for tuning but I can use it for logging data. Another point was also mentioned to me is that with the wireless system I can operate a communication link to my pit crew. But in most cases the level of racing we are doing (30 minute races) there not much a pit crew can do for you if you had a problem. One stop and your out as far as any top 5 finishes.

West-se

That would be quiet easy to do using a remote control program to control the laptop in the car via the laptop in the pits. If you have XP Pro you can use remote desktop otherwise you could use a free program called VNC. You will have to experiment with wireless reception, 802.11g is rated at 300' line of site without any obstructions, I've not read the specs on the latest 802.11N but could be more, you'll definetly need an antenna or some type of signal booster, I've not personally tested wifi at speed, but it sounds like a fun and very doable project.