--===============21563107629870526== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-0kp03nBveUud0OOqU0IC" --=-0kp03nBveUud0OOqU0IC Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Not really. even with these probes (70 - 100 $US is cheap) measuring pH in solids is extremely difficult. The probes will also need to be calibrated regularly and cleaned very regularly as they rely upon diffusion across a membrane which can become blocked by solids. the probes also need to be kept wet or they will fail. On Wed, 2004-09-22 at 21:43, Claudio Martin wrote: > Hy all: > I=B4m looking for a cheap ph sensor for soil. I=B4m working on a gardeni= ng project and i need to check temperature, humidity and PH. These three m= easurements will be interfaced to a PIC ,after that the PIC will display t= he values. I=B4ve seen some PH probes on internet, but they are kind of exp= ensive(70-100 U$D) for this project cause i need to place many of them in d= iferent places. Does anybody know if there is other cheaper way to mesure P= H?. Thanks=20 > _______________________________________________ > http://www.piclist.com > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=-0kp03nBveUud0OOqU0IC Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux) iD4DBQBBUZZFld78u9zTPjkRAiesAJjuo58I/y3yYbhTDNa/3iv6P932AJ0eMe10 Z4UOcxrhRzk/dkHmoFBsYg== =AdYC -----END PGP SIGNATURE----- --=-0kp03nBveUud0OOqU0IC-- --===============21563107629870526== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit _______________________________________________ http://www.piclist.com View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --===============21563107629870526==--