8/31/21 4:46 p.m.

Hi all,

This is my first post. I have been lurking for (quite) some time because whenever I'm goooogling for something racing+diy I tend to end up here - so I though it was time for a bit of pay-it-back :-)

Disclaimer: I am an IT guy, no even worse I'm an IT manager ;-) so by continuing reading you accept that I have absolutely no clue what I'm doing. This could break, burn, short or disperse radiation on an unknown wavelength. Also I am not offering 24x7 support, in fact please consider this 'grabware'. You grab it, and see if you can make it work for your purpose.

That being said, I'd try to help if I can ;-)

Background: I was looking for some corner weights, but was not able to find anything suitable (read:cheap) enough in my  part of the world. So I went online and found some cheap(ish) parcel scales from eBay. They are only rated for 300kg, but since my car is in the 975-1050kg range that was ok. AFAIK most 'budget' scales are constructed more or less similar so I would assume other rated scales would work just as fine.

Solution: I found out that cutting the original wiring of the scale, replacing it with 4x HX711 load cell amplifiers connected to an Arduino worked perfect. Adding in some LCD displays, wiring,  network cables, 3D printed parts and a plastic box and I ended up with this:

(With my foot on FR scale just to show some numbers)

I'd be happy to share wiring diagrams, arduino code etc. if anyone is interested. 

I had some of the parts, connectors, wiring etc, but estimated cost is around €335/USD400.


alfadriver GRM+ Memberand MegaDork
8/31/21 4:49 p.m.

Where did you find load cells?  That's really cool.

APEowner GRM+ Memberand SuperDork
8/31/21 4:51 p.m.

Welcome. That's a heck of a first post and a very cool project.  I'm sure I speak for others when I say that we'd like to see whatever you're willing to share.

tfunder New Reader
8/31/21 4:51 p.m.

Load cells are in the scales ;-)

Edit: this is how the scales look like out-of-box. I cut the black DB9 cable and solder the 4 wires coming out of the bottom of the small green print to the HX711. Connect HX711 to the Arduino, calibrate the scale (lot's of guides online, ie.

Repeat 3 more times.


tfunder New Reader
8/31/21 5:08 p.m.

In reply to APEowner :

Here's wiring diagrams and Arduino code (v.09x) for starts.



bgkast GRM+ Memberand PowerDork
8/31/21 5:19 p.m.

This is awesome, thanks for sharing! I just started messing with an Arduino with my daughter.

APEowner GRM+ Memberand SuperDork
8/31/21 5:32 p.m.
tfunder said:

In reply to APEowner :

Here's wiring diagrams and Arduino code (v.09x) for starts.



Cool.  Thanks.  I've never messed with an Arduino.  Am I correct in assuming that LiquidCrystal_I2C.h is a library module?

tfunder New Reader
8/31/21 6:01 p.m.

In reply to APEowner :

Yes :-) Ctrl+Shift+I in the Arduino dev tool to open "Manage Libraries" and add.

..and you also need to add the "HX711.h" library.

californiamilleghia SuperDork
8/31/21 6:12 p.m.


What other things have you built ?


tfunder New Reader
9/1/21 12:21 a.m.

In reply to californiamilleghia :

I have been playing around with Arduinos, but this is actually one of my first "finished" projects.

I do have a breadboard-prototype of a servo "Throttle Blipper" with configurable timing and amount ;-) I'll share if I get it done ;-)

MadScientistMatt UltimaDork
9/1/21 6:35 a.m.

Nice work!

2002maniac Dork
9/1/21 12:20 p.m.

nice work!

sevenracer Reader
9/1/21 9:34 p.m.

Nice work indeed.


Years ago, I briefly entertained building something similar with a USB analog i/o board plugged into a PC, but I couldn't find reasonably priced load cells that were up to the task. These days, there's probably something suitable and cheap out on Alibaba or similar.

03Panther UltraDork
9/1/21 11:23 p.m.

In reply to tfunder :

Love the disclaimer! You're gonna fit right in.

I'm a Peterson (yes I know, its spelled wrong! Typo on a birth certificate), a Mickelsen, a Jacobson... and.... a Garret / Hicks. Dad's father, from Denmark, jumped ship as a wee lad of 14 or so in NYC. Dad's mom came over at 16 to be an au'pare (however ya spell that babysitter word). Mom's Dad was born here in 1919 to Danish immigrants, and Mom's mom's family had been in Williamsburg since the beginning.

Anyway welcome from a square head (and proud of it!)

tfunder New Reader
9/2/21 1:38 a.m.

In reply to 03Panther :

Thanks :-) You could actually argue your name is spelled as intended "Son of Peter" just 'translated' :-) 


Our Preferred Partners