Need more information on ph sensors

Hi guys
I want to measure the ph of the soil although the product Gravity: Analog pH Sensor / Meter Kit For Arduino:
https://www.dfrobot.com/product-1025.html
is for aqueous solution.Also Analog Spear Tip pH Sensor / Meter Kit:
https://www.dfrobot.com/product-1668.html
says it can be used for semi solid but very costly.
I was curious about if there is any other cheaper alternative to measure ph . I also found this :
https://www.electronicscomp.com/3-way-s ... bUQAvD_BwE
How ths device is measuring ph at such low price ,is it reliable/accurate?Please guide.
Thanks

Translation:

Hi guys,

I want to measure the PH of the soil although the product is for aqueous solution: Analog pH Sensor / Meter Kit For Arduino

Also Analog Spear Tip pH Sensor / Meter Kit says it can be used for semi solid but it is very costly.

I was curious about if there is any other cheaper alternative to measure PH.

I also found this: 3 Way Soil Meter. How this device is measuring PH at such low price, is it reliable/accurate? Please guide.

Thanks

pH probes are by nature very delicate, so its a difficult problem to make a robust enough probe - if
you want cheap, I think you have to buy litmus paper and do it by hand.

That 3-way tester doesn't have a pH sensor, so it can't measure pH. It uses different metals in
the probes in an attempt to measure electrochemical potentials, so its likely measuring a proxy for pH,
not pH itself.