next topic »

[on:]

Hi.. 

I think there is a problem with my project I am recently doing..

When I attach my gsm/gprs shield, Icomsat, in my arduino uno.. I getting a weird high value from my sensor.. Example I connect a potentiometer to my analog pin I am getting a normal value but when I'm receiving SMS I'm getting a weird high value until the message is shown.

[Reply #1 on:]

Yes, that does sound like a problem.

It could be bad wiring, it could be bad code, it could simply be the fact that mobile (gprs) signals are incredibly noisy and a massive source of interferance.  I'm sure you've heard the "bip, be-dip, be-dip, bip, bip, buuuuurrrrr, bip, be-dip" noises...

[Reply #2 on:]

You need to filter out RF on your sensor, and keep the GSM antenna well away from sensitive parts of the
circuitry.  If the sensor is basically DC, try putting 100pF and 10nF ceramic directly across the output to
shunt the RF pickup.  GSM transmits relative high power radio signals (a lot more than bluetooth or WiFi).

Also ferrite bead on the sensor leads right next to the Arduino may reduce the antenna-effect.

[Reply #3 on:]

Yup.. thank you.. I will do that tommorow.. but how to apply it to piezo element disk.