Acs712 with St7735 Display!

[jgu1]

Hi all!

Yes it´s me, who need help again, hope it´s ok

Using an Arduino Mega, ST7735 display and an ACS712.

To avoid flicker as much as possible in the display I only update when Amp is changing so I use " If new <> from old write the new and update Old"

It work fine in simulation , but in real world it update all time, without changing amp? Same issue with the ILI9341 display, but working fine with a
LCD display 4X20 serial. very stable.
I have try to use all kind of capacitors over the supply, ect.

Am I doing something wrong in my examble, or is there another way I can avoid or solve the problem or "flicker during update value", please.

Thank´s in advance

Jorgen

[mnfisher]

I would guess that the current reading is fluctuating enough to cause a refresh.

Maybe check if AmpOld and Amp differ by a certain 'threshold' amount and see if that helps?

Martin

[jgu1]

Hi Martin!

Know I could count on you Thank you.

Already tested, no matter if I ground the ACS712 or use a battery, its always update, strange?

[mnfisher]

How quickly does the sensor refresh? - maybe add a delay in the loop. It will surely help - but maybe not in the right way (1s delay == 1s refresh)


Amp and oldAmp - are floats, cormparing them for equality might not work well..

Something like abs(oldAmp - amp) > 0.1might do the trick?

Would need to be fabs (#include <math.h>) or create your own (if(x < 0) return -x)

Martin

[jgu1]

“Amp and oldAmp - are floats, cormparing them for equality might not work well..”
What i also thought, I try to change to byte 0-255 for test, same.

I Will test your suggest later today, you hear, Thank’s.

Br

Jorgen

[jgu1]

I placed this in an calculationbox before compare

AmpOld = (AmpOld - Amp) > 0.1 rigth or ?

But still the same Neither the delay solve the issue.

[mnfisher]

Need to check if its negative as well (> -0.1 (hence the fabs - which would need to be in a C block)) - can you print out the readings? Do they look reasonable?

Martin

[jgu1]

Hello MArtin!

Sorry take your time. When I remove the USB programming cable from the arduino it get much more stable

So this have some disturbtion on the reading. Thank you for your always helping.

Br Jorgen

[mnfisher]

Sounds like an interesting (and sensitive) sensor...

Good that you are getting some readings now.

Some displays are also very 'noisy' - I had issues with an SSD1306 - which introduced a huge amount of hum into a circuit.

Martin