Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Interfacing keypad,LCD and RF wireless transmitter module

Status
Not open for further replies.
T

tschen

Junior Member level 3
Joined
May 10, 2007
Messages
27
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,466
I need help with assembly PIC programming to interface a keypad,16X2LCD and wireless transmitter module (TLP434A). Anyone have any ideas?
 

Re: Interfacing keypad,LCD and RF wireless transmitter modul

here are some projects that i got from the internet in my archive i hope it helps.
you can do some search if o get more.

Added after 4 minutes:

oh sorry this are the schematics
 

Re: Interfacing keypad,LCD and RF wireless transmitter modul

Thank you for the file.
 

Re: Interfacing keypad,LCD and RF wireless transmitter modul

I was wondering if there is any other encoder/decoder chip that works the same as Holtek 12D and Holtek 12E???

I need other substitution for the chip urgently.
 

i want little help plz help me.
i am using transmitter tlp434A and receiver rlp434 with AT89c51 at receiver's and at transmitter's end as well .i want to transmit (just testing) digit 18 (converted to ASCII,from binary).when i conect the TXD pin of MCU (at transmitter's end) with the Rxd pin of mcu (at receiver's end).it perfectly transmit didgit 18 and is displayed on lcd perfectly but when i tranmit it by using tlp434 with rlp434 receiver,so digit is not displayed on lcd but i can see only cursor:-(

note tht i connected the txd of mcu to the data in of transmitter directly,at transmitter's end and the data out (digital),of receiver ,i connected to mcu's rxd pin at receiver's end.
kindly help me
 

maybe an interface problem to the transmitter/receiver. Can you post the interface circuit MCU-TX/RX?
 

Think the problem is related to the transmitter.
uC Supply is 5V, TLP supply is 12V.
TLP Data input is specified VHigh= Vcc-0.5V and therefore needs a minimum input voltage of 11,5V to recognize Logic-H, which cannot be provided by the uC.
There are two solutions:
- change supply of the TLP from 12V to 5V (maybe this will lower the range of the radio)
- Add an additional Pullup-resistor (~7K5) to the TX Data line and connect it to 12V.
 

Brother i am actually using tx with 5v but i am receiving garbage...
 

Nice to know. Any further modifications compared to the schematic???
Have you checked the baudrate? 4800kbaud is maximum.
Have you checked/adjusted the radio frequencies?
 

i tried al baudrates bt no thng changed.in tlp434a module u cnt adjust .these module r preadjust ...(i m told).so shd i adjust? Nd how?thr is sm thng like Pot is there on my receivr which is fixed i cnt change
 

Have you connected a suited antenna?
According to datasheet, there is a trim pot on the receiver to adjust frequency. Put a scope on LinearOut pin and adjust Amplitude to a maximum while transmitting data.
But without more information from your side it is almost impossible to locate the failure...
Maybe one module is simply damaged...
 

i m using just a wire 4 both,transmiting nd receiving antenna.on thng more whn conect the modules to my hrdware and if i turn of the transmiting end the receivr keep ön receiving garbage values!.could u tel me y? Regarding pot actually the face of the pot is stuck with a red type plastic.so its fixed .so now wt can i do?i m told the modules r tunned by default ,is it correct?
 

i m using just a wire 4 both,transmiting nd receiving antenna.
Click to expand...
Assume you use seperate wires, one for TX and another for RX. Length should be 30-35cm
Regarding pot actually the face of the pot is stuck with a red type plastic.so its fixed .so now wt can i do?i m told the modules r tunned by default ,is it correct?
Click to expand...
New module should be trimmed and a turnkey solution. Are your modules Factory new?
on thng more whn conect the modules to my hrdware and if i turn of the transmiting end the receivr keep ön receiving garbage values!.could u tel me y?
Click to expand...
Strange... Seems the problem is on the RX side. Have you decoupled the power with appropriate blocking caps? Otherwise radio may get distorted by ripple of Vcc. take a look here
Without exact schematic it is impossibe for me to help you locating the error. Sorry!
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top