[SOLVED] dtmf controlled robot

kunal123 · Apr 23, 2013

hello,

**broken link removed**

i connect led between tip & ring 2 led's cathode at ring & led's anode at tip, when i pressed any key of cell phone keypad led glows, i think i successfully pass DTMF tone to MT8870, but not getting output, please suggest me some solution to solve these problem.
my cell phone is HTC desire c, NOKIA 2700, NOKIA C5-03.

D.A.(Tony)Stewart · Apr 23, 2013

I do not see any supply filter caps. Perhaps wires are too noisy, so twist the wires or use telephone cord. Stray hum can interference with signals on a breadboard.

Show schematic

chuckey · Apr 23, 2013

The circuit does not show an earth return to the mobile's connector, no Vcc voltages are shown, the circuit relies on the crystal being the right frequency - is it?. Have you checked all the IC pins with a DVM against its data sheet?
Frank

betwixt · Apr 23, 2013

Try connecting a 100 Ohm resistor across the jack connections. The jack on many moble phones is multi-functional and to be sensed as having a headphone attached (which is what you want) they need a small current to flow through them.

Brian.

[SOLVED] dtmf controlled robot

kunal123

Advanced Member level 4

D.A.(Tony)Stewart

Advanced Member level 7

chuckey

Advanced Member level 6

betwixt

Super Moderator

Similar threads

[SOLVED] dtmf controlled robot

kunal123

Advanced Member level 4

D.A.(Tony)Stewart

Advanced Member level 7

chuckey

Advanced Member level 6

betwixt

Super Moderator

Similar threads

Privacy & Transparency

Privacy & Transparency