one person kart scales

Steve Kay · Posted: Wed Feb 10, 2010 7:44 am Post subject:

Mike,
Have you ever done that at the track as a tuning tool? Do you chase the track's grip or do you have your learned set-up and let the track come to you?
I could see it on a test day, but I don't think I've ever seen it at a race, probably because of most of us not having a crew and being too busy with common maintenance. That and the fact that there are so many other adjustments available. I do agree though. Get the seat right and you're 85% of the way there.
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Italkart '09 Leopard

Mike Goebel · Posted: Wed Feb 10, 2010 8:48 am Post subject:

joseph hollinger · Posted: Wed Feb 10, 2010 9:15 am Post subject:

got it.
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A lie gets halfway around the world before the truth has a chance to get its pants on. -- Winston Churchill.

norton wallace · Joined: 26 Jan 2010 Posts: 21 Location: Canada, Ontario,

I have to report that with the generous help from Joseph I did manage to purchase some used fairbanks scales off ebay and finally completed my own personal kart scale tonight!

Although I haven't get a chance to scale the kart yet but just by playing with the scales and you can get real time weight on each corner as well as front to back ratio is everyone could dreaming of especially in your own home.

I have to thank Joesph again for his countless reply to my emails and guide me through the process patiently.

Kudo to Joseph for all his hard work and generosity on sharing his skill and knowledge on writing such a wonderful program and the beauty of this project is I can have my own personal, extremely accurate commercial quality one man kart scale in my own home for less than $200!

Very Happy

Thank you again Joseph you are the man!

Steven Palmer · Posted: Sat Apr 17, 2010 8:40 am Post subject:

I just purchased a set of these scales this morning. Would it be possible for one of you who have already done this to PM me with some tips on the best way to set up this system? It would be GREATLY appreciated!
Also, has anyone tried using a laser level on these? It would be pretty easy to level these to within 1mm (or less!) of each other that way. And, it would be more easily repeatable.

Steve
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GPI Racing
Wildkart Warrior/Vortex ICC/Hoosier Tires

Peter De Saegher · Joined: 26 Mar 2010 Posts: 57

C of G Height Calculator
http://www.mediafire.com/?zzqwmtnmib1

I have tried , but the link does not work .... ?

Mike D'Ambrogia · Posted: Sun Dec 05, 2010 10:26 pm Post subject:

did anybody ever tear a Weigh Max scale apart to see if there was a way to get the data, or if the electronics are just driving an LCD? they sell on amazon for $30/ea

http://www.amazon.com/Digital-Shipping-Weight-Postal-Scales/dp/B001AQAW9C/ref=sr_1_1?ie=UTF8&s=electronics&qid=1291612825&sr=8-1

for those that might be interested -- there is a Fairbanks Ultegra SCB-9000 shipping scale for sale on Craigslist in Ann Arbor for $60 -- http://annarbor.craigslist.org/bfs/2082186975.html

another guy is advertising a few different models of serial capable scales for $50 each or less, have an email in to him to see how many he might have access to. will post once he replies
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'07 TM FTR 125 stock moto

Mike D'Ambrogia · Posted: Mon Dec 06, 2010 8:08 am Post subject:

I know this is an older thread, seemed timely for me so I'm going to continue to resurect it. I'm a software programmer and a technologist, so I'm intrigued by what Joe has done.

So I ordered a $40 weighmax w-4820 scale from amazon this morning to tear into once it gets here. I spent 2 minutes on google trying to understand LCD displays and how they are driven. It looks like all LCD communication is done by serial or parallel communications -> http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1281077368/0, and parallel comm gets converted to serial at the device by a daughtercard strapped to the back of the display. 4 wires connect to the display. It looks encouraging. The other nice thing about the weighmax is that it is powered by 9vdc which means you should be able to run 4 scales off of a single lantern battery which makes it a bit more portable. It should be easy to mod a $4 9v lantern to run all the scales if all else goes well. If successful this would make for a $164 scaling solution.

The worst case is that I'll have a digital scale with an LCD readout unit on a long pig tail cord that I'll be able to see while sitting in the drivers seat, I can use the Kart Smart program (http://www.nacoma.cc/kartsmart.htm) to track kart weights.

more to come
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'07 TM FTR 125 stock moto

joseph hollinger · Posted: Mon Dec 06, 2010 4:46 pm Post subject:

Here's one possible issue: good scales like the Ultegra use strain gauges convert weight to a signal. In fact, the Ultegra has four strain gauges in each scale and a microprocessor to convert their outputs to weight. Cheap scales use a gear driven shutter. An LED directs a beam through the shutter and a photo diode is used to count the number of time that the shutter interrupts the beam. The problem with this second type of scale is that they shut off after some predetermined interval and if you then turn them back on without unloading them they think that they are at the zero point. That's why you can't use digital bathroom scales to weigh karts. You get one reading and then all of the scales shut off and zero themselves in the loaded configuration.

I don't know about the scale you bought, but that's something to watch out for.
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A lie gets halfway around the world before the truth has a chance to get its pants on. -- Winston Churchill.

Mike D'Ambrogia · Posted: Mon Dec 06, 2010 5:13 pm Post subject:

good thing Amazon has an awesome return policy. good to know, scale arrives Wed, I'll know more on Wed night, will post a quick update as soon as I do
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'07 TM FTR 125 stock moto

Mike D'Ambrogia · Posted: Wed Dec 08, 2010 8:36 pm Post subject:

well, unfort. nothing to report. Amazon whiffed on their 2 day shipping, so continue to stand by to stand by.

edit: just checked UPS site, the package is in Oakland, about 3 hrs away so chances are it will arrive tomorrow
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'07 TM FTR 125 stock moto

Jason Bane · Posted: Wed Dec 08, 2010 8:58 pm Post subject:

Keep the info coming Mike, I'm interested in how it works out.

Mike D'Ambrogia · Posted: Thu Dec 09, 2010 11:46 pm Post subject:

well, good news and bad.

bad is that the display isn't a driven LCD and as such there is no serial type data driving it. so using Josephs program is out with this model.

the good news is that this seems like a reasonable electronic scale at a decent price. the display has an auto off that turns off after 4 min of inactivity. if the weight on the scale changes, say by wiggling in the seat, then the scale stays on. once there is no change in the weight for 4 min then the scale turns off automatically. the pigtail cord stretches the display unit about 5-6'. the unit is driven by either a 9v battery or a wall charger. display is clear and easy to read. you can calibrate the unit with a 50 kilo weight (~110 lbs).

that's what I've learned. hope it helps somebody.
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'07 TM FTR 125 stock moto

Cesar Rull · Posted: Sun Oct 21, 2012 12:51 am Post subject:

nice thread. Very Happy