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Type: Posts; User: harvie

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  1. Closed: Re: Attiny85/Atmega32u4 internal differential ADC to replace HX711?

    @KlausST Yes. you are true. There is thermal drift. I initialy noticed just the high frequency noise and didn't realized there is thermal drift. So i just went back and checked again.

    When i heat...
  2. Closed: Re: Attiny85/Atmega32u4 internal differential ADC to replace HX711?

    Just did similar test with HX711 module at maximum gain of 128

    Got step around 0.0015 uV, with input pins shorted the noise was causing fluctuation of +-0.1 uV

    So i am pretty confident that you...
  3. Closed: Re: Attiny85/Atmega32u4 internal differential ADC to replace HX711?

    Ok, so i've been doing some tests with Arduino ATMega 2560.

    I've used ADMUX = 0b10001011 which means following:

    internal 1.1V reference
    adc0 negative, adc1 positive
    200x gain

    It got me...
  4. Closed: Re: Attiny85/Atmega32u4 internal differential ADC to replace HX711?

    Does it mean that when i set AREF to 40mV, i will get approximately the same behavior as HX711?

    Also the atmel has some kind of gain setting, i am not sure how that applies to AREF.
  5. Closed: Attiny85/Atmega32u4 internal differential ADC to replace HX711?

    Hello,
    i've recently found that Attiny85 and Atmega32u4 come with differential ADC capabilities.

    I was messing with load cells (strain gauge wheatstone bridges) used as weight/force sensors....
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    Closed: Charge Pump Whistle (ST662/MAX662)

    Hello,
    i've designed circuit using ST662 charge pump IC (5V to 12V; 30mA; 400kHz; Clone of MAX662) and the first prototype PCB we've assembled produces slight audible whistling under load. (We are...
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    Closed: Re: Doppler "radar" motion detector design

    I've found datasheet of RCWL-0516 module:
    https://img.filipeflop.com/files/download/Datasheet_rcwl-0516.pdf
    Updated version: https://github.com/jdesbonnet/RCWL-0516

    It seems to explain...
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    Closed: Re: Doppler "radar" motion detector design

    Yes. Antenna is left side. It's double sided and usualy has some funny shape. IIRC this one has some kind of circle on the other side.

    These modules usualy range between 2 to 30 GHz, depending on...
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    Closed: Re: Doppler "radar" motion detector design

    Cool. Thanks for info. I was worried if the output analog signal has enough amplitude (voltage) to be detected by internal ADCs of common uC (eg. atmega).
    I don't need direction sensitivity, but it...
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    Closed: Doppler "radar" motion detector design

    In recent years i've noticed rise of extremely cheap motion detectors based on doppler effect in RF domain. There are lots of them, one example looks like this:

    155248

    To my knowledge there are...
  11. Closed: Re: FPC connector with 0.5mm pitch, short pins under connector?

    Just for the record: Board came out great, the soldermask separates the pads enough. But there are three minor issues with this approach.

    TLDR: if you want perfect board, don't do this. otherwise...
  12. Closed: Re: FPC connector with 0.5mm pitch, short pins under connector?

    Is solder mask needed in such case? i am worried what will happen if there is none. by default the kicad has minimal soldermask web width set to 0.25mm, i had to lower it to 0.1mm, which is absolute...
  13. Closed: FPC connector with 0.5mm pitch, short pins under connector?

    I am designing board with 0.5mm pitch FPC connector using Kicad and mihosoft freerouting. It got me something like this:

    154883

    Is it OK that pins are shorted in this way or am i supposed to...
  14. Closed: Should I replace DMM fuse with resetable PTC?

    Hello. In our workshop we have few cheap digital multimeters and from time to time someone manages to accidentaly "measure" current of car battery or something. Usualy these guys are incapable of...
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    Closed: Re: Strain gauge touch probe for CNC digitizer

    BTW the renishaw design is based on something called "Maxwell Kinematic Coupling"
    https://en.wikipedia.org/wiki/Kinematic_coupling#Maxwell_Coupling
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    Closed: Re: Strain gauge touch probe for CNC digitizer

    These guys even designed load cell / strain gauge into the PCB design:

    https://www.duet3d.com/DeltaSmartEffector
    https://reprap.org/forum/read.php?178,783399

    150882

    > This is a principle of...
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    Closed: Re: Strain gauge touch probe for CNC digitizer

    > What about piezo disc?

    Yes, i've considered this. Problem with piezo sensors is that it only reacts to change in pressure, not the pressure itself...

    > I presume the output of the shown...
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    Closed: How to wire Strain Gauges without canceling each other?

    Hi,
    i am experimenting with various CNC touch probe designs and i've came across following setup using straingauges CA-glued to elastic frame holding the probe tip. I will probably use aluminum or...
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    Closed: Self driving piezo used as CNC touch probe?

    Hi! I am thinking about building piezo probe for my CNC. Classic piezo probe design is basicaly "piezo knock detector" circuit using either opamps or uC with ADC sensitive enough to pick the piezo...
  20. Closed: Re: Can i use TRIAC Optocoupler like MOC3041 directly to switch AC appliances?

    It seems that "photomos relay" is the right way to go. Like the CPC1510. It has high voltage transistor rather than triac and it's designed to drive ac load directly. While still being available in...
  21. Closed: Re: Can i use TRIAC Optocoupler like MOC3041 directly to switch AC appliances?

    I was never saying that i will use it to drive 1A load. I was talking about 10 to 50 mA. Which is about range that most semiconductors i've seen so far can safely handle.



    That sounds better...
  22. Closed: Can i use TRIAC Optocoupler like MOC3041 directly to switch AC appliances?

    Optocouplers like MOC3041 are usualy used to drive TRIAC which then switch some mains powered circuit.

    http://obrazki.elektroda.pl/9878013000_1486957343.jpg

    I was wondering if it would be OK to...
  23. Closed: Re: Measure in-circuit ESR using (LCR-T7) atmega component tester?

    It costs 20 AUD (= 14 USD). You can get newer version cheaper. Eg. LCR-T4 for 11 USD:

    http://obrazki.elektroda.pl/8332626800_1482618968_thumb.jpg
    ...
  24. Closed: Re: Measure in-circuit ESR using (LCR-T7) atmega component tester?

    You can plug different kind of probes in them :) The description says "in circuit". Cheap multimeters also usualy don't come with aligators, but i still buy them extra :-) However having only...
  25. Closed: Re: Measure in-circuit ESR using (LCR-T7) atmega component tester?

    So i've found these two:

    MESR-100 (42 USD)
    Claims to use 15mV peak-to-peak
    ...
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