I found this DFRobot load cell kit: http://www.komputer.de/zen/index.php?main_page=product_info&cPath=24&products_id=284 It uses a HX711 as ADC: http://www.aviaic.com/UpLoadFile/hx711_brief_en.pdf
I made good experiences with the ADS1231 http://www.ti.com/lit/ds/symlink/ads1231.pdf as ADC for a load cell. Now I wonder what the main differences are between ADS1231 and HX711 ? Has someone compared results from both chips?
You have any comments on how the two chips compare? I'd like to hear your take on it.
First of all: I wrote the initial post some days ago. In the meantime I have a DFRobot kit on my desk also.
It is interesting that the sketch I use for the ADS1231 (based on the lib attached to this post http://forum.arduino.cc/index.php?topic=131086.msg1570340#msg1570340) is also working for the HX711. So the protocol seems to be quite the same (I did not check this via datasheet till now). I did not check it vice versa for the ADS123 and the HX lib. I also noticed in the datasheets that the HX711 needs a bit more power. On the other hand the gain is fixed 128 on the ADS and at least one channel of the HX711 is customizable relating to gain. And of cause the HX711 has two channels while the ADS1231 has only one. But in case you need a second channel take the ADS1232
But my initial question refers more to the accuracy and sensitivity. In the ADS1231 datasheet you can read
- Input EMI Filter
- External Voltage Reference
what I could not find for the HX711. So my question would be::Is there a quality difference on the data with noisy power / wabby battery source or other disturbances?
One advantage of the TI ADS1131 over the HX711 is that it has the power down switch that shuts off current to the sensor bridge when the ADC is in Standby or PowerDown modes. This is critical for battery powered applications.
Also, the HX711 cannot be sourced from Mouser or Digikey (except as SparkFun breakouts), which means many US PCA companies won't be able to build boards with the part.