RF Serial Data Link {through USB}





How to transmit data using a cheap RF module through USB. The circuit receives energy from the USB port (may provide 100mA and with some programming you can reach 500mA)

List of Materials:
1 - One pair of RF module (like Laipac RLP/TLP433A) look after it in sparkfun.com (they have different operating frequencies: 315, 433 and 917(?) MHz)
1 - TSUB3410 - Serial-to-USB integrated chip (QFP-32) from Texas Instruments.
1 - One Power LED (you may skip it)
1 - 3.3V LDO (Low Drop-out) regulator - to connect in the +5V (+/- 10%) line from the USB.

Start with the "walkthrough.pdf" guide, after it we will improve the wireless link to be connected to an USB port.

! ! ! - Altought it may look like a very simple circuit (just the RF link), you may find some rocks in your pathway.
I still don't know if this is a reliable circuit..so be carefull where you are going to use it. Be advised to try this circuit ONLY when you are in a good mood! if not go play PS2...otherwise this can damage your parasympathetic nervous system!

Step 1: Checking RF Modules

First of all you must go exactly through the steps written in the PDF file attached to this site ("walkthrough...")

It´s a good idea to check first the modules. Do it on a breadboard, it works? Fine, move to the next step... or check connections, wires, supply (did you turn it on?).

You can check the wireless link with an osciloscope or using any (hyper) terminal software. Check the maximum baud rate! (mine 4800bps). You may need a MAX232 chip, it is a Serial level converter...
[ PC >> MAX232 >> TX ] ~~~~~~~ air ~~~~~~~~ [ RX >> MAX232 >> PC ]

email me...may be I can help you!

Step 2: Improving the Circuit to Use USB Instead the Serial Port

If you are fortunate as I was, you can use a Rapid Protyping Machine like the LPKF C-Series. This way it allows you to use a little bit more complicated SMD (Surface Mounted Devices) IC.

Some times is quite annoying to change batteries, so we decided to supply the receiver from the USB port. It´s very simple, the USB delivers +5V (+/-10%), so the only thing you need to do is attach to it a voltage regulator (using Low-Dropout regulators is a good idea).

To interface the RF receiver with the USB we are using the TUSB3410 Serial-to-USB module. It´s a very simple chip and you may find it at, almost, every big supplier (?). We power it with 3.3V, regulated from the USB port. (Don´t forget to install the drivers that you may download from Texas Instruments web site)

When I connected the Receiver to the TUSB I had a problem. The Serial In port from the TUSB3410 has a strong pull-up resistor, so every data that I received was with a threshold of 3.3V (look at the internal schematics of SIN port in the datasheet...). So we plugged a buffer between the receiver and the TUSB4310.

Straight foward! Just follow the basic schematic and it must works perfectlly.

Step 3: Soldering / Testing

At the right part (where is written RX0 and TX0) you must connect your modules.



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    14 Discussions


    4 years ago on Introduction

    I’m working on a project which is about making a rescue
    robot . I have struggling with it for 4 months and now all the mechanical works
    had been done . but I’m facing difficulty in make the robot to work with rf
    module can u plzz help me…

    I want make transmitter and receiver that can control the
    motion…I mean that receiver should have control 8 dc gear motor and each dc
    motor should have a forward and backward botton to control the motion ……can u
    kindly help me with this project ….if u can make the circuit board diagram for
    the PCB ….or any other suggestion plz reply……mail me at “sunny1995gagan@gmail.com”

    1 reply

    i am trying to transmit serial data over this module using usb to ttl converter but its not responding


    6 years ago on Introduction

    hi friend
    i am Ajay. i want to make 8 channel RF receiver and transmitter. i men i want to
    operate 8 dc motor revers and forward throat RF remote control ..using my engineering project then how can i make.. give me some instruction..pls


    7 years ago on Introduction

    How do I connect from PC->RS232->RS232TOTTL->RF Modules?
    The RS232TOTTL has rx ,dx pins, but the RF Module just has 1 Data pin?


    11 years ago on Introduction

    hello if somebody knows like handling to modules RF tlp433a and if somebody has handled some vos modules that trasmitan. thanks

    1 reply

    Reply 11 years ago on Introduction

    No, there is not enough bandwidth to send that amount of data. But you should use a bluetooth wireless link or even any wi-fi camera...or if you want to spend some time at the workbench you should try to do your own RF (FM?) transceiver. Anyway good luck!


    Hey Barmak, there is a way to use this device to connect a webcam and make a "wireless webcam"


    12 years ago

    Kick-ass Instructable on the Laipac-USB wireless. The last page throws an error( “ERROR 403: can not view: E9XCJPBXSCEPYPFGNC”), probably a their-problem, not a your-problem. I’ve done a 916MHz wireless dingus for monitoring a piece of mobile equipment using the RFM TX6xxx series parts(www.rfm.com). Wayyy smaller than the Laipac, and sealed. You can get 1Mb/sec both ways with the TR1100. It rocks, seriously. Great to see your work, just had to drop you a line. Bravo.

    1 reply

    Reply 12 years ago

    man, i just tried the link and it seems to be OK...otherwise you may find it at sparkfun.com. And thanks for the advise...they are really cool modules, those RFM!


    12 years ago on Step 1

    Some times it won´t work at the desired baud rate, so when i try with lower ones like 2400 or 1200 it improves the link quality. F#&K! (distance between the RX/TX pair is a good explanation)


    12 years ago

    "there are 10 types of people in the world, those who read binary, and those who don't"

    1 reply

    Reply 12 years ago

    Hey, whats your e-mail barmak??? I wanted to ask you a few specific questions