Troubleshooting guide - DIY Logitech G27 Load cell mod

[@LuismiCamocha]

I bought this load cell from Marton and I had some issues yesterday trying to assembly. I asked him and he answered me and give me a great feedback. Finally I resolve the problem and the load cell is perfect, I've been all day trying to get used to it and it's so nice, i feel very different now when I drive. Totally recommended this project, but even more recommended anything from Marton, thanks for all!

[@tutisek9464]

What was your problem?

[@botak333]

I have a problem sir, when i connect all the output signal always 4,9v i turn already the pot still 4,9v sirr, what wrong.?

[@chadog]

Hi there. I was wondering if there are other alternatives to 122P? I'm having a hard time looking for one :(

[@ignacioherrero9374]

Hi… those circuit are able to manage only one load cell from weight scale???thx mate, great job!!!!

[@gerzsone30]

No, it has to be in pairs

[@ignacioherrero9374]

@@gerzsone30 And how I must to place them?, i dont Understandt the layout. I would place under a pedal but I dont know how.

[@marc_orso7058]

Hello, I would like to contact you to ask you a question about the load cell and the pedals you made.

[@spirospo1992]

I redone (3rd time ) the board with diferent ic trim cap and loadcell and still i dont get the same voltage when i check middle with red or black..also no response from the load cell @Màrton Bakos if you got any clue why i fail at this i would be grateful.

[@LeHieu-ie4dp]

past ok. I need to make one like that. can you do it yourself?

[@s_n9210]

Hello Márton, is there any way I can use the load cell mod through arduino, bypassing Logitech's firmware?

[@pjenglund]

You can take the output from the load cell to an analog input on the Arduino and use analogRead to get the signal. Use the map() function to reverse the output if necessary (e.g. 1023->0 to 0->1023). Then use the Joystick library to output a signal that is recognized as a joystick in Windows. Search and look for "amstudio" on youtube and "AM-STUDIO/USB-5-AXIS-CONTROLLER" on GitHub for the code (althoug read the comments, there seems to be some errors in the code on github. Note that the output range from the load cell should be as close to 0 - 5V as possible for best resolution. Hence, the Gain potentiometer is a good idea.

[@PALOSDEAJO]

Great job! Can I hire you to make a design for me?

[@humberto367]

you're nervous, you're shaking!

[@danielvelazquez8138]

Hi Markos, I did everything as you have it, but it doesn't work. I tried to change the ina 122p for a 122pa and the same does not work, I have the same 104 ceramic capacitor, you can help me with this I would be very grateful!

[@matej7627]

i tried 3 ina122p and it doesn't work for me. can you resolve the problem?

[@psamtam]

i tried 4 ina122 and still doesn't work... the output is always 4.5v when supply voltage is 5v

[@erwinramos6240]

No change in voltage output when i try to bend the loadcell😢. I think my IC is busted😭.

[@Thesuvari34]

İna 122 better hx711 or better. Which one should I choose

[@gerzsone30]

Choose ina122 Hx711 is slow

[@Thesuvari34]

@@gerzsone30 stm32 & arduino leo

[@PALOSDEAJO]

How can I contact you?

[@CYBORGRACER]

it will help me a lot, because mine doesnt work. MY CHIP IS A INA128P, IS CORRECT? MANY THANKS

[@gerzsone30]

Your chip should be fine. Last time I received INA129P instead of the 122P I wanted, but it worked just as well. The difference is only signal to noise ratio and some tolerance values.

[@CYBORGRACER]

@@gerzsone30 nice. thanks man! Regards

[@MrStimpydk]

thought I reply on this about my trouble. I now have got the correct trimpot 1k, but still flickers. I have tried to ground the negative but no changes. I have meassured the loadcell, I have different results than yours. Its a 5 wire 50g loadcell, but the yellow wire is not used. (www.tinkerforge.com/en/shop/load-cell-50kg-czl601.html) It has input ohm at 405 and output ohm at 350. My messurements is green to white 350 ohm black to red 404 ohm green or white to red or black 289 ohm. When trimpot is adjusted to give reasonable signals its at 56 ohm. Since I dont have 1k ohm between black and red the setup might have be diffferent? can you guide me on the right path?

[@gerzsone30]

The trim pot value is very small. It means the load cell you have has very low sensitivity. The amount of amplification needed can be barely handled by the chip, therefore it amplifies the noise as well. Try a different type of load cell.

[@MrStimpydk]

@@gerzsone30 thx for your feedback.

[@MrStimpydk]

its a bit weird because tinkerforce have their own module to connect with it but it uses the "lesser good" hx711 chip. www.tinkerforge.com/en/shop/load-cell-v2-bricklet.html

[@MrStimpydk]

@@gerzsone30 For another loadcell, I guess I should look the input and output ohm level. If a loadcell has input at 1000 ohm and output ohm at 1000 ohm, would that be perfect?

[@gerzsone30]

I would not say it depends on the resistance values, but rather the amount of change in resistance. It can't be measured normally. I'm not a professional, just guessing