YOUMILE 4pcs DIY 110lbs 50KG Half-bridge Body Load Cell Weight Strain Sensor Resistance + HX711 AD Module

Printed a support for strain gauges, measuring 20kg accurately and consitently, gas bottle measurement system for motorhome. Rpi hx711 pythonlibs really easy to use

I haven't used these properly yet, but there is an error in the 4th diagram, showing the wiring connection colours. It should be - R1: input+/power+, R2: output+/signal+, R3: input-/power-, R4: output-/signal-. The output +/- might be reversed - I haven't tested it properly yet and I will update this review when I have.

I used one of these cells (wired with two 1% 1K resistors to form a Wheatstone bridge) to make a load cell brake pedal for sim racing by converting a Logitech pedal set. It works fine for the purpose coupled to a ATMEGA 32u4 Arduino but there are a couple of non-obvious gotchas...For the uninitiated, each unit is a half-cell of a Wheatstone bridge; the red wire is the centre-tap (sense wire), and the black and white are the terminus(5v/0v excitation). Wiring diagrams are available on the net, but many are for 4 cells; they can be used as 4, 2, and 1 cell.1) When you build something more permanent make sure all connections to the HX711 board are soldered correctly. *ANY* moveable connections will cause havoc with the readings because the system is so sensitive. You will need connectors for prototyping, just be aware of this source of error.2) Get an HX711 library (I used "HX711 Arduino Library, by Bogdan Necula & Andreas Motl) and make sure the cell is powered-up (it's a library command) or you might have problems with consistent readings: don't power the cell up & down in the main loop if you are taking rapid readings.3) If you read the cell too fast (i.e. less than 50ms) you might get incorrect readings. Check the cell is ready before reading every time. Look at the examples with the library.4) The cell can have a different no-load reading on start-up sometimes. Check for this.5) It is a little slow (few milliseconds lag) for rapid applications.6) I divide the readings by 1,000 as the rest of the digits are more or less noise.7) If speed is not required, use a rolling cumulative average algorithm over something like 4-16 samples.8) The wires are a little flimsy so don't stress them.Other than those it works fine for this application, and would make a reasonably good custom scale from 0.5kg-200kg, but use something else for small scale measurement.

The listing states it comes with a module and 4 x load cells. I got a module and no load cells. Totally useless so sent it back.

If you're trying to do anything that detects humans standing on it, pushing, or anything really, this is a decent solution.It's pitched as something for a scale but I think it's probably more suited (since scales are so cheap, even smart ones) as a sensor for load. You know, like a supermarket checkout or whatever, or maybe an alarm when someone picks up your precious thing. All good ideas.It seems to work well, theyve given you a lot of info in the screen shots so be sure to save them lest they disappear.packaging is sparse as usual.

This is my second review as apparently you can't post links, even to datasheets.Google !"HX711" to get more details on how to use this board and you'll get wiring and code examples galore.The board itself is well made, and with a bit of fiddling is producing consistent results. Basically the four strain gauges vary in resistance and this circuit is an analogue to digital converter. You just have to map the digital values to the weight you're putting on it.

Can't really fault it for the price. The only complain I have with the cells is that the wires are way too thin and difficult to solder. I attached a photo next to a du pont cable for comparison

Like most of these sensors this does not come with a manual and it is not as straight forward to use as some of the others. This definitely requires you to have some skills with electronics and also to know how the sensor functions. The different sensors need to be calibrated to one another and there is quite a lot of fiddling in the set-up. However they are definitely useful. I have not tested their precision and accuracy yet as I need a set of standards but they do provide a useful demonstration tool.