ht12e for 434 not working.

[vikaskumardabas]

Hi
I've just made rf transmitter but failed. And I started over from starting.
Now I've doubt that if ht12e is not working..

Ht12e on breadboard, 5v supply,1Mohm to oscillator ,
Now after power on, it 5v on Vcc and osc out pin,2.4v on osc in pin and 0v on all data and address pin. I think data pin must show some voltage.
And one more, TE pin is made ground and Vcc but no change on any data or address pin. And 0v on data out pin also.

 

[uday mehta]

there is no need to give vcc to TE pin. for checking that ht12e is working or not, connect an led to pin 17 when you connect the TE pin to ground led will be glow.(actual method use CRO because you can't see the blinking at 434 mhz so it will look like continuously glow) connect +ve of led to pin 17 and -ve to ground. if it glows, when TE is ground, it means ht12e is correct. and to know the voltage at remaining pins check the data sheet. what if your receiver ckt is not prefect. { if you open the data pin of ht12e it takes high and if connected to ground it takes low. } also check the voltage of osc. pins. it has be different.

 

[vikaskumardabas]

I've checked it.
It has 1v in multimeter on pin 17 and as per your idea led glows.
When TE made ground. Is that OK?
Is my ic OK?
And one more thing as per ckt it must have some voltage at data pin that will be grounded to make data but mine shows 0.18v in multimeter.What is that means? I think it is already ground?

Reply from Vikas dabas

 

[vikaskumardabas]

Try this link .. .I think it might help you..
ASK RF Transmitter and Receiver.

As I told u I had tried this ckt but now I want to know that how to get output from ht12e when data input is not possible as mention above. Why data pin shows ,0.18v instead of some 3v.

 

[uday mehta]

no, ckt is not already ground. for your confirmation check the output of IC using CRO. Its looks like ASK modulated. please send me your receiver ckt diagram.

 

[stillcrazy]

Have you tried bypassing the RF stage and connected Pin 17 of the 12E directly to Pin 14 of the 12D to see if the encoder and decoder are working?