I'm a newb to load cells... with that I'm working on a project that is merely a concept at the moment but plan to bring to a prototype. Can I use a load cell to measure weight (in lbs...pounds...) using a pivot to push force up against the load cell instead of the normal sitting of an object on the load cell.
I have attached a rough sketch. The load cell is in a cylinder tube with a small tube inserted inside that. A pivot point will be a rod that goes through both cylinders. Appreciate any advice.
Not sure why its sideways in my preview... it's not that way in my photobucket....
Google load cell for a quick education. They cannot measure anything, including weight. They are strain gauges that change electrical resistance when they are "strained". You can use that change to cause a change in electrical voltage, when amplified can be measured by an Arduino A/D converter. The resulting value, 0 -1024, can be calibrated to give you the approximate weight of the object pressing the strain gauge in the load cell.
Your drawing will work to give you the weight or force, depending on your calibration.
Paul
Load cells (or the ones I've used) tend to be quite sensitive to the smallest of changes, but they also tend to bounce around a bit as well - you don't get the exact same value every reading. What sort of weight are you going to put on the pivot?
What load cell are you proposing to use? If it's a beam type, the active end needs to be isolated from the larger tube (which is not how you've drawn it). If it's a compression type, then what you've drawn should be ok.
I'm looking to hang some weights and get results, under 25 lbs worth of weight... I was going to use a flex force sensor but I read they weren't as accurate as a load cell.
I think I'm going to use the beam type, the S style compression ones seem too big and are more expensive.
So the beam style needs to stick out of the pipe and be attached to the secondary pipe at the end?
I'll try to sketch up what I think you are talking about... I'm new to load cells so this is all new to me.
One last question? Is there a way to make them water proof?
is this what you are saying it needs to be?
A. Upper diagram is what I meant by isolating the active end of the load cell from the larger/outer tube.
B. The middle diagram is similar to your second concept. Be sure "L" isn't too long.
C. Lower diagram is simplest.
It is not clear what problem you are trying to solve, or why you need tubes and a pivot. What is the "big picture" of your application?
Regarding waterproofness...I don't know. Check the load cell datasheet.
