I had to make a RF remote control.
Transmitter has 7 switches. When a switch is pressed, the transmitter must send a specific frequency.
Typically we need to split from 500Hz to 2Khz for 7 switches.
This transmitter remote will be powered by 3v battery. Please note the stand by current must be as low as possible to preserve the battery energy.
Receiver: This will be powered from 5v to 12v. It is your choice. It will be ON all the time and the frequency must be received when the transmitter sends the signal. (I have separate circuit which will process this frequency.)
Important Note: I have already made transmitter and receiver using standard RF TX with a uC, RX Module .
But it did not work as expected.
Why?: I have used pic controller that will always be in stand by mode (<1uA). When the any switch is pressed, uC will wake up and turn on a port pin and the RF module is powered as it is tied to the port pin. This is were the problem happened. The port pin could not drive the RF module properly. It gives < 2.3v and the RF module fail to work. It needs proper 3v. even though the current is <20ma, but pulsed current is more by RF TX module. Also the decoupling caps are giving pulse current while switch on.
I need a solution to solve this..(Can not use a buffer.. Transistor has vce sat and Mosfet will not work at 3v Vgs.. need some other solution)
Suggest a new circuit, workable solution
Please, Please, Please bid only if you have experience on this topic.
If i get a right tech-pair, i have lot of projects to do together.