HT12E

[nazirie]

hi...i'm on my final year project using RF to send data in wireless. i'm already study about the encoder HT12E for 4-bits. my already circuit had a piezoelectric that detect force. the signal then amplified with amplifier. my condition here is that to grab that signal and send in wireless to the receiver. how i'm connect the HT12E to my circuit.

[yonghui]

hi,

looking at the picture ur attached. its seems like a simple rf transmitter.

but i recommend u to use RFmodules for transmit and receiver, follow the link below

RF transceiver for 2 ways communication:
http://cytron.com.my/viewProduct.php?pcode=RF-TRX-2.4G&name=RF%20Transceiver%202.4G

all RF modules:
http://cytron.com.my/listProductGroup.php?pid=ACo3Oy4pAxccPQkaDQ4eBup/nbueXc2!!!!!8AjlynVjwNo=

[nazirie]

hi,

thanks yonghui for ur concern

i'm already looked at the link given and understnd the operation of the module. can i know how to make connection between already my attachment circuit to the module. should i use encoder HT12E. i dont know how to connect my circuit to the RF modules.

[Idris]

Are U using microcontroller? This is sample of low freq RF project.
http://www.cytron.com.my/viewProduct.ph ... tg=&store=

[nazirie]

i'm not using microcontroller. i'm poor in programming.

[royalstorm7]

piezo output is very small and short....u must amplify and prolong the signal to fullfill the RF transmission...interface and connection are not so difficult....have fun...gudluck

royalstorm7@yahoo.com

[nazirie]

hi royalstorm
can u give me some idea about the connection.the signal already have the amplifier by the factor gain of 3.

[ABSF]

I'm already study about the encoder HT12E for 4-bits. my already circuit had a piezoelectric that detect force. the signal then amplified with amplifier. my condition here is that to grab that signal and send in wireless to the receiver. how i'm connect the HT12E to my circuit.

The circuit you used is designed for sending audio tone or voice to the other end. Audio has amplitude and frequency. But your piezo would only have a fix voltage level when a force is applied which is hard to interwork with your circuit. I guess your circuit is taken taken from a FM wireless MIC curcuits if I am not wrong.

To convert your force sensor to something that can be measured and transmitted by RF, my best guess is to convert it to a digital signal using an ADC. In your case where you dont want to use microcontrollers, the HT12E can transmit 4 bits at the same time so your transmitted force can have 16 levels ranging from lightest to heaviest. Though the measurement is fuzzy, it is still doable.

The connection is from sensor->ADC->HT12E-> Freq Mod of your Transmitter. On the receiving end you need the output of your RF receiver connected to a decoder HT12D->DAC->voltmeter.

Allen

[nazirie]

Thanks ABSF

This circuit from the previous student and i my task is to continue to transmit data in wireless. from what u have mention, the signal from piezo don't need to amplified right?

Thanks for ur opinion n knowledge. this is really help. i think i must continue my research and get some information to continue this project.

[yonghui]

hi,

probably the output from the piezo can be amplified with op-amp, or bias the op-amp as comparator whereby when piezo being touch it trigger the comparator to switch the signal level.