Hx711 and grovepi+

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Hi There,

I have purchased a ADC for Load Cell (HX711) and have the grovepi+ attached to a RPI 3 model B. I don’t have much experience with the grovepi+, but have previously run ADC boards for the HX711 from GPIO pins of the RPI and python. I am not sure how to go about it with the grovepi. Could anyone help or point me to resources that give some examples for coding digital boards for the grovepi. The other option for me is use the grovepi board but connect it to the gpio pins using the grove to 2.54mm Pitch Pin Header wires? I am not sure which would be easier.

Thanks so much for any help.

kind regards

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First, for anyone that will follow this thread - a datasheet for the HX711 is available here.

Second, Did you buy your GrovePi+ from Dexter_Industries/Modular_Robotics? If so, support for Modular Robotics products is now available at support@modrobotics.com while this forum is now a “user community” where hopefully a GrovePi+ user will chime in to help you also.

I am not a GrovePi+ owner, nor had I heard of the HX711 before, but I will offer an opinion to the answer of your question “Connect HX711 to GrovePi+ or direct to RPI?”

  • You state you have previous code for the direct to RPi solution; that will be the easiest solution, no?
    You will have to determine if the GrovePi+ is using any of the pins your software needs, and remap to unused pins if needed.
  • Looking at the GrovePi+ “DataSheet” shows two serial ports “RPi Serial” and “Serial”, with TX/RX so those are out since the HX711 seems to want a Clock/Data/Ground/5V kind of connector which is similar to I2C but from a quick glance at the grovepi.py code, I don’t see a serial example or serial mode for any of the I2C or ADC connects.
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Thanks for the reply and adding additional information that I left out.

The Hx711 adc is from seeed studios, I will follow up with them for any further information/support about the board/grovepi integration.

I agree with your first point that using the GPIO pins is likely the easiest route as I have code that works for this already. If I don’t hear back from seeed then this is likely the best option.

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Good bloody luck with that!

Seeed Studios is famous for their lack of support and what limited support they do supply is often wrong.

Seeed Studios stuff is primarily directed towards the experienced crowd as you often have to look at schematics and datasheets for the chips involved to figure out how to use their stuff.

If you can find schematics, we might be able to help. Or at least give hints.

As has been stressed in many postings, part of the fun of this hobby is the sense of discovery; facing what seems to be an insurmountable barrier and then discovering a solution.

We’ve all been there.

  • @KeithW and @cyclicalobsessive and their adventures with ROS, (and a host of other challenges I don’t remember).
  • My own adventures with a joystick controlled robot, recalibrating the new battery’s state-of-charge meter and multi-booting the GoPiGo.
  • There’s a whole thread here, (with over 120 replies!), about Seeed Studio’s pH sensor.
  • And so on.
     

So it is with you.

This challenge is yours to accept if you wish.

If you do decide to continue, please post progress and results here.

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Question:

Is there any particular reason/requirement to use this with the Grove-Pi? What exactly are you trying to accomplish with this?

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I have several other (better supported) I2C sensors (two mcp9600 thermocouples and a Time of flight laser) that are working well through the Grovepi+ and when I saw the HX711 sensor was “compatible” I thought great, can have all the sensors running through the grovepi and no need for prototype boards / soldering.

I have just had some time to try the seeed ADC board and run it directly to the GPIO pins that are passed through the Grovepi. Connecting the board this way and using the python code supplied here I can read the sensor. I am still waiting for some parts so that I can complete the physical build and test whether the values it is reading are indeed correct.

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Glad you found a solution.

I really hate to trash-talk a supplier, but Seeed is in a class of it’s own.

BTW, SparkFun is advertising “load cells” and “load sensors” (load cell = 4 load sensors in a bridge configuration). SparkFun, (along with Adafruit), are suppliers that I constantly recommend as their products are top-notch and the support is fantastic.

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