DYI Load Cell Handbrake

[Michal Burisin]

I'm building a load cell handbrake. I got all the required parts now:

Handbrake
Load Cell
Controller Board

I have a question about the Leobodnar Load Cell Interface LC-USB 16-bit.

When I connect it to PC, all the axis are getting small input.

I'm using single axis for handbrake, on controller there are 2 other axis I'm not using (X and Z rotation - these are for potentiometers connection).

When I calibrate controller in Windows it shows input even on unplugged axis (X and Z rotation). X is skipping around 50 - 55, Z is skipping around 250 - 265.

Load cell connection is Y Rotation and it's giving input of around 220 even when I'm not touching it.

When calibration is complete I have problem that it's continuously skipping and the axis are constantly engaged even when disconnected or for load cell that is connected, there is small amount of input.

When I try to map controls to game with load cell controller connected, the controls are mapped randomly to load cell various axis as they are constantly engaged and skipping.

Most games have deadzone settings, which could work. But there is problem when mapping controls in any game, I would have to disconnect load cell controller to be able to map anything beside load cell.

Does anyone has any idea how to solve this? Is there a way how to completely disable axis on load cell? Is there a way how to set deadzone in windows? Maybe some virtual controller software can do this?

I will be updating this thread as I solve the mechanical part of attaching load cell to handbrake / adding washers for smooth handle pressure on load cell etc.

 

[Bitacaia]

My first guess:
Your load cell isn´t well connected!!!

In my Leobodnar board, when i connect the Load Cell, the Z axis stops jumping and goes to 0.

You sould use this software: DXtweak (there is another, but i don´t remember)

Tiago Viana

 

[Michal Burisin]

My first guess:
Your load cell isn´t well connected!!!

In my Leobodnar board, when i connect the Load Cell, the Z axis stops jumping and goes to 0.

You sould use this software: DXtweak (there is another, but i don´t remember)

Tiago Viana

Thanks! You lead me on correct path, DXtweak is outdated and unsupported in W10, but I found DIView available for download directly from LeoBoadnar. It's possible to set deadzones etc., solved my issues.

As for connection:

I have it connected like this:

White - (output) connected to +5V
Red: + (input) connected to (+IN)
Black - (input) connected to (-IN)
d) Green: + (output) connected to GND

I hope I got it right, it works fine besides those jumping values.

 

[Michal Burisin]

Today I was reworking the handbrake which I had already done and it reminded me this topic, so I took some pictures along the way.

It's based on this handbrake.

I used table stool leg, 3 cm radius, 10 cm long.

I expanded 2 holes to fit it onto the handbrake.

I drilled holes, the one with bolt goes through the plastic cap to hold it in place against pressure. The second hole is for cable from load cell.

I used this load cell, 100 kg variant.

I used combination of spare spring from pedals I got and some rubber washers. I separated the layers with 2 swiss francs coin, damn expensive washer, but it fits perfectly I used 3 of them in the end.

Basic plastic box and load cell interface.

I drilled 2 holes to the plastic cap to keep the loadcell firmly in place (probably not necessary).

Addon done.

 

[Michal Burisin]

For some steps I didn't have photos which I have done before. For example I removed some handbrake parts which made the handle position adjustable and bolted it together. I find having the adjustment unnecessary and I'd rather have it rock solid.

Also I added some thin washers to remove any wobble which was present at various joints.

And here's the result:

Really easy to do and I love it!

 

[bberger]

Oh boy, that stool leg idea is genius! You just solved a problem on my pedals that has been bugging me for years (or even a decade tbh).