Inside Z-Box

[Phil2360]

Can't help myself. Gotta have a look inside things

to see what's there.......

http://static.cl1.vanilladev.com/ballofspray.vanillaforums.com/uploads/FileUpload/fb/9ebb829596e99eeb42b7c1693d3ad9.jpg

 

Assume the little chippy in the bottom left is the accelerometer.

[colo_skier]

This is the product link

http://www.analog.com/en/mems-sensors/mems-accelerometers/adxl103/products/product.html

 

here's the micro in there

 

http://www.keil.com/dd/docs/datashts/philips/lpc2114_2124.pdf

 

[ForrestGump]

Interesting. We use the same accelerometer in canbus equipped datalogging equipment in race cars.

[Phil2360]

@rico The GPS used is a Garmin GPS 18 5Hz. It communicates over an RS-232 interface, or what is otherwise known a serial port on older computers. (Mice & modems mostly used to use these ports).

 

So the GPS port in the master module is just a serial port that can be programmed for any purpose.

 

So it's logical now that the GPS talks to the Z-box first & then the Z-box talks to the master module, communicating both GPS & accelerometer data.

 

As it contains it's own micro processor, it must also be capable of doing some processing on both sets of raw data before it talks to the master module.

 

Here's a Diagram of the GPS's connection to a PC.

http://static.cl1.vanilladev.com/ballofspray.vanillaforums.com/uploads/FileUpload/5f/52368465d9c8509856d7bb9853d288.jpg

 

[Phil2360]

 

[colo_skier]

If i were to hazard a guess I would say that the zbox is "massaging" the raw GPS data being fed to the Stargazer based on Accelerator feedback information and settings in some look up tables based on the a b c settings entered on the multi line guage. Since Stargazer can be used without the zbox the zbox must somehow "trick" Stargazer into calculating position, speed and acceleration form differing the raw data fed to the Stargazer unit.

[Phil2360]

@colo_skier there would be no need to "trick" Stargazer, as it now has totally different software loaded, so the stream of serial data coming from the Z-Box will probably contain both positional & accelerometer data.

 

If the serial port is running at 19200 Baud, that's 1920 Characters per second, so plenty of data could be communicated in a given second.

 

Agree that the raw data would probably be pre-processed in the box as the NMEA data from the Garmin is really not what the system would be interesting.

Probably communicates either distance traveled, or instantaneous speed for every 5 Hz update.

 

[colo_skier]

@phil2360 Agreed "trick" was probably the wrong term to use. Augment would have been a better term. There must be some computing going on to warrant the micro in the z-box. As that is were the accelerometer is at I was assuming some sort of extra information content being added into the data stream that Stargazer uses. I heard somewhere that the ZO uses 2 ARM 7's which is quite a lot of micopower to analyze NMEA data. Therefore they must be doing a lot more vector and speed math form other data streams. Bottom line is if the system works it's a good thing for us older boat owners.

[Phil2360]

Bump for @rodltg2.

It's roughly 2" square in size.

 

[rodltg2]

2" ! Well I can easily make room for that.

[Chuck_Dickey]

We tried Z-box at our lake this weekend and I'd have to give it a thumbs up. My friend has a 1998 Ski Nautique and we had a 195 lb. fairly strong skier at 35off@34mph. Accurate times and a very similar response as my 2011 PS197 with ZO. Our lake has a short setup as well.

 

I think one of the keys may be; the reduction transmission get up very quickly and Stargazer settles more quickly, so no surging was present with Z-box version. Not sure it will be the same on a 1:1 trans.

[usaski1]

good to know.. keep those reports coming!

[skinut]

Geeks