user64817

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• read an high precision adc like hx711

  @user64817 started

  • 36 comments
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  @Gordon replied
• read an high precision adc like hx711

  in General • 8 years, 5 months

  

  you have here all the versions, tests I've made.
  the main one is hx711.js, the other ones are derivated, with the attempts based on this thread's advices.
  actually, I have a working project with 2 load sensors, working with arduino, I'm still unsuccessfull with espruino, not stable and precise enough.

• read an high precision adc like hx711

  in General • 8 years, 7 months

  

  the value are still not stable.
  if you want I can send you my code, if you have a hx711 to test it.
  values returned are 25000 ... 31000
  arduino's are much more stable.

• read an high precision adc like hx711

  in General • 8 years, 7 months

  

  I just tried. values read with espruino are more stable, but still much less stable than the arduino values.
  the signal sent on sck is very fast. sck high time is 1,5 microsecond.
  but those burst are composed by much faster high/low very small bursts, and seems to confuse the hx711.
  So this is not precise enough for me, until I have a solution like arduino, that will sent stable precise bursts.
  anyway, thanks for your help.

• read an high precision adc like hx711

  in General • 8 years, 7 months

  

  Hi. I've tried with the Gordon get()'s fonction.
  it works, but the value read is not "stable" comparing to arduino.
  the code here :
  https://learn.sparkfun.com/tutorials/loa­d-cell-amplifier-hx711-breakout-hookup-g­uide
  calibration code normally continuously reads a 0 'lbs' value, on arduino it works, on espruino, the value goes from 0.004 lbs up to -1000 lbs sometimes, meaning that the adc is not read correctly, surely because of too long high time for the CLK pulse (value > 60 us puts to power down mode)
  I've used "compiled" directive.

• Help with HX711 Strain Gauge

  in Interfacing • 8 years, 7 months

  

  yes it's me.
  sorry, I've mistaked on the other post. I'll post on this thread now.
  I managed to have a 22microsecond pulse with digitalPulse(..,.., 1000/65000) for a 65khz freq.
  digitalwrite alternance just makes a 10ms perior for high time, this is too long for hx711, we have a 50microsecond limit according to the specs for the clock.
  I've checked with an oscillo.
  I'll finish my hx711 javascript port and post it there.

• read an high precision adc like hx711

  in General • 8 years, 7 months

  

  sorry, I've mistaked.
  I managed to have a 22microsecond pulse with digitalPulse(..,.., 1000/65000) for a 65khz freq.
  I've checked with an oscillo.
  I'll finish my hx711 javascript port and post it there, and on the other thread.

• read an high precision adc like hx711

  in General • 8 years, 7 months

  

  Hi,
  I've tried to connect the hx711 to espruino to measure a loadcell
  unfortunately, the hx711 pd_sck pin asks for a pulse of 1 and 0 (24 to get the bits of reading) then 1-3 bits for the gain setting.
  and the max time for the 1 period is 50microseconds (pcd_sck high time)
  cdn.sparkfun.com/datasheets/Sens­ors/For­ceFlex/hx711_english.pdf

  and the espruino min delay for a digitalwrite is 160 microseconds. I've measured with my oscilloscope.

  so the hx711 is "too fast" for the espruino.

  Do you have an idea how I can get the adc values ?

• Weight Sensor (Load Cell)

  in General • 8 years, 7 months

  

  Hi,
  I've tried to connect the hx711 to espruino.
  unfortunately, the hx711 pd_sck pin asks for a pulse of 1 and 0 (24 to get the bits of reading) then 1-3 bits for the gain setting.
  and the max time for the 1 period is 50microseconds (pcd_sck high time)
  https://cdn.sparkfun.com/datasheets/Sens­ors/ForceFlex/hx711_english.pdf

  and the espruino min delay for a digitalwrite is 160 microseconds. I've measured with my oscilloscope.

  so the hx711 is "too fast" for the espruino.

  Do you have an idea how I can get the adc values ?