Description: The SparkFun Load Cell Amplifier is a small breakout board for the HX711 IC that allows you to easily read load cells to measure weight. By connecting the amplifier to your microcontroller you will be able to read the changes in the resistance of the load cell, and with some calibration you’ll be able to get very accurate weight measurements. This can be handy for creating your own industrial scale, process control or simple presence detection.
This version of the SparkFun Load Cell Amplifier features a few changes that you specifically asked for! We have separated the analog and digital supply, as well as added a 3.3uH inductor and a 0.1uF filter capacitor for digital supply.
The HX711 uses a two-wire interface (Clock and Data) for communication. Any microcontroller’s GPIO pins should work, and numerous libraries have been written, making it easy to read data from the HX711. Check the hookup guide below for more information.
Load cells use a four-wire Wheatstone bridge configuration to connect to the HX711. These are commonly colored RED, BLK, WHT, GRN and YLW. Each color corresponds to the conventional color coding of load cells:
The YLW pin acts as an optional input that is not hooked up to the strain gauge but is utilized to ground and shield against outside EMI (electromagnetic interference). Please keep in mind that some load cells might have slight variations in color coding.
Note: Special thanks to Bodge for supplying the Library for the HX711!
Based on 12 ratings:
Followed the hookup guide and it worked perfect with my Arduino Uno! Very easy to use with a load cell.
Had it up and publishing(Uno and Ethernet shield) to broker in 30 minutes.
I knew Sparkfun was the place to go to get the components I needed for our experimental sugar rocket motor test stand with data logger. Now we can fine tune the Buder Rocket Boy’s sugar rocket engine formula this winter perfecting a replacement for commercial hobby rocket motors. The XH711 along with the 10kg straight bar load cell (TAL220) was a perfect fit. Precise, compact and at a great price. Thanks guys for designing and supplying awesome stuff!
I was comparing this to some of the others that I’ve picked up and really don’t see much in a difference for readings other than it is a bit more expensive. Its nice that they at least have dropped the price a little from when I bought it.
I do have to say the Sparkfun library is great as its probably the most comprehensive when setting up a load cell or tieing in 4 load sensors.
It took me a little researching on the differences between a load cell and a load sensor.
You can tie 1 load cell into the hx711 or you can tie 4 load sensors into this using a wheatstone bride.
Connection to cell are best done soldered directly to load cell. Awesome amplifier.
It gets the job done. The labels are clear and easy to read. The example code had only one minor issue: include <name> vs include “name” and worked just fine after it was resolved. Thanks for a nice web site with all the cool stuff.
This was surprisingly accurate. My load cell was for 780 g max. I calibrated it for 32 g, (two ½-13 nuts) weighted with a scale accurate to .001 g and then tested it up to 320 g. It was spot on.
The one problem I had was in finding the calibration constant. Mine was far different (much larger) than the example given in the tutorial, and the calibration program would have taken forever to slowly find it. I modified the program so it would take bigger steps and zero in on the constant faster.
This really saved my partner and I for our project and the product got to my home faster than expected.
Well designed, works as advertised, documentation and SW is freely available. It took just few minutes to power it up and get good reading. I am very satisfied with this product.
I have not yet been able to work on my scales projects. I will update this review once I’ve completed the two projects.
This was my first time using load cells and did not know what to expect. I read the tutorials and got it wired up easily. I got it hooked up to my Arduino and with the library that Sparkfun provides I got it running with no fuss at all. The one problem I had was that the rate that it was updating was not very fast. After some reading I realized it has a jumper on the bottom which if you bridge will increase the data rate. Once I did that it worked perfectly for my application.