Piezoelectric transmitter

[brimsant]

So currently I've built this piezoelectric harvester that stores the rectified power in a capacitor which is also connected to a comparator. What I want to happen is that once the voltage of the capacitor surpassed the threshold of the comparator (haven't set it yet but 2-3V), I plan to discharge the capacitor into a transmitter that sends off a signal. Then, the capacitor goes back to charging.

My main issue right now if that I have no idea how to make the transmitter, can someone help guide me on how I could go about making it?

Thanks in advance

 

[danadak]

Transmitter -

1) Power
2) Mode, wireless, wired, type, frequency....
3) Tx rate
4) Desired distance
5) Data size
6) Environmentals

 

[brimsant]

Transmitter -

1) Power
2) Mode, wireless, wired, type, frequency....
3) Tx rate
4) Desired distance
5) Data size
6) Environmentals

I'm not exactly sure of the specifications but I just need it to send a signal that can be recieved in around 1m range and that I need it to be low power (<3V)

 

[ZipZapOuch]

How are you going to store energy in your 22uF cap? Right now, the charge immediately discharges through your two 1k resistors. A fully charged capacitor will discharge in under a second if you can ever get it charged with the leak you have.

And, 3v isn't a "power" unit as you stated above. Watts is power. How many watts do you need snd how long do you need the circuit to be active to make a connection and transmit some information.

 

[brimsant]

How are you going to store energy in your 22uF cap? Right now, the charge immediately discharges through your two 1k resistors. A fully charged capacitor will discharge in under a second if you can ever get it charged with the leak you have.

The resistors should control the threshold voltage of the LTC1440. How it should work is that the capacitor won't dicharge until it charges above the threshold.

The only reason the resistors are 1k right now is because I don't know how high I want the threshold to be yet.

 

[ZipZapOuch]

I'm not exactly sure of the specifications but I just need it to send a signal that can be recieved in around 1m range and that I need it to be low power (<3V)

Also, define "transmitter". The chip you show is an RS485 .transceiver but for wired applications.

 

[brimsant]

Also, define "transmitter". The chip you show is an RS485 .transceiver but for wired applications.

Sorry, I should have been more specific

I plan to eventually put the device in water so right now I am looking at something like a piezoelectric transducer as a transmitter.

 

[ZipZapOuch]

Sorry, I should have been more specific

I plan to eventually put the device in water so right now I am looking at something like a piezoelectric transducer as a transmitter.

What kind of signal do you hope to transmit? Wireless, wired and which protocol?