Latest Version of IRDA-USB transceiver

[jacky]

Hi,

here is the latest version of the IRDA USB transceiver. I modified the board so that it is easier to built and replaced the TFD4100 with a 4300, which is the newer part.

I will be in Taiwan running a humanoid robotics summer school as well as lots of other travel for various things, so I probably won't have much time to continue working on this.

CU,
   Jacky

[guerra]

Jacky, thank you so much for your work. I just finished reviewing your circuit. In the version that uses TFDU4300 the Vcc of TOIM4232 was connected to 5V but the maximum tolerable value for that component is 3.6V. I noticed you had this fixed in the other versions that did not use TFDU4300 but used the obsolete TFDU4100 instead. So I just fixed it by connecting the Vcc of TOIM4232 to the 3V3OUT pin of FT232RL.

You told me your design was originally made for etching, but since we need to order printed circuits for the other boards anyway then I decided to make a slightly more compact design. I also added a ground plane and made the Vcc lines a little thicker than the other lines. I tried to keep vias far from the pads and to align the SMD resistors and capacitors in order to make it easier to sold by hand. I also found a link to each and every component in Digi-Key and made a BOM list. Some small resistors and capacitors have to be purchased with minimum quantity of 10 units, but this should be no problem because they are really cheap.

The new design that I made has nearly 1.7 square inches. In BatchPCB they charge 2.5 dollars per square inch plus 10 dollars of handling, so I guess one single board would cost around 15 dollars (plus postage, of course). I already run the CAM job and generated the Gerber files with the specs of BatchPCB, so I guess this board is ready to be ordered.

Check the files in the attachment.

[guerra]

I posted a reviewed recharger here.

[guerra]

I posted the reviewed programmer here.

[guerra]

Message from Jacky:

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Hi Rodrigo,

I am not sure which board is the most appropriate message, but please post this message to the forum

Here is my current status with the IRDA transceiver. I built my own latest version since I used a PCB plotter here. Do not use the files I posted on the board, since it still uses the old TFDU4100. I will upload my current board version with the changes metioned below sometime next week. It should be relatively easy to forward port them to your board. I also wrote several test programs that I will add to the upload.

The circuit works, but I had a couple of problems.

1.) The BR/D line (Pin2) on the TOIM4232 was not working correctly when controlled from DTR of the FT232. I wrote a test program to drive DTR and it changed etc., but the TOIM4232 did neither receive or transmit. After several hours of checking things out I still could not find the problem. It all looked fine with the scope on the pins.

I changed the BD/R line and connected it to GND instead of DTR and it works fine now. I can transmit and receive with the circuit. But without the ability to drive BR/D, we can not reprogram the baudrate and are limited to 9600 baud. I will try a pull down next Monday.

2.) My concern is still the angle of the IRDA transceiver since it is limited to 30 deg. and 1m length as per the IRDA standard. However, I think we may be able to add our own IR diode and drive it. If I have time I will investigate this further.

3.) I am wondering whether I should connect RTS to RESET on the TOIM4232. This is assuming that I get 1.) to work correctly. I found out that it is impossible to read the current board rate, so it may be better to be able to reset the TOIM4232 to a known baud rate

I am currently very busy and probably will not be able to do much more work on this. I will try and send you my working board so that you can test it with the actual robots to determine distance and angle for the reception.

CU,
   Jacky

[guerra]

Hi Jacky,

Thank you for your help so far! My comments below.

Do not use the files I posted on the board, since it still uses the old TFDU4100. I will upload my current board version with the changes metioned below sometime next week. It should be relatively easy to forward port them to your board. I also wrote several test programs that I will add to the upload.

I understand, but the board that I posted is based on a version of your board that uses TFD4300 and not TFDU4100. Myself and some other teams also already ordered that board and the parts. You can see the files here. So I really hope we can fix the board not having to make a new one... 

1.) The BR/D line (Pin2) on the TOIM4232 was not working correctly when controlled from DTR of the FT232. I wrote a test program to drive DTR and it changed etc., but the TOIM4232 did neither receive or transmit. After several hours of checking things out I still could not find the problem. It all looked fine with the scope on the pins.

I changed the BD/R line and connected it to GND instead of DTR and it works fine now. I can transmit and receive with the circuit. But without the ability to drive BR/D, we can not reprogram the baudrate and are limited to 9600 baud. I will try a pull down next Monday.

I see. The BR/D (pin 2) of TOIM4231 connects to DTR (also pin 2) of FT232RL through a via in the board that I posted. So it seems easy to use a wire and add a pull down or even to connect to GND and cut the connection to DTR if this is the case. We could also try to calculate if baud rate 9600 is such a big problem or not, because this is already much faster than last year anyway.

2.) My concern is still the angle of the IRDA transceiver since it is limited to 30 deg. and 1m length as per the IRDA standard. However, I think we may be able to add our own IR diode and drive it. If I have time I will investigate this further.

This is also easy to add to the current project as well.

3.) I am wondering whether I should connect RTS to RESET on the TOIM4232. This is assuming that I get 1.) to work correctly. I found out that it is impossible to read the current board rate, so it may be better to be able to reset the TOIM4232 to a known baud rate

Well, for RESET removing the USB cable and plugging it back again does not sound as such a big deal for me either.

I am currently very busy and probably will not be able to do much more work on this. I will try and send you my working board so that you can test it with the actual robots to determine distance and angle for the reception.

We will be glad to test. Our boards and components should be arriving soon as well, so maybe if you give me the updated circuit schematic I can try to fix the board. I want to make a video and pictures showing to the teams how to build the board once we succeed figuring out a working design.

[fcportugal]

Hi all,

 My pcbs arrived (finally) so i am building the circuits.
 
 Can someone please post the necessary changes to ir-transmitter circuit?
 Please include a list of components preferably with a digikey link (or similar).


Tanks, best regards,

João

Fc Portugal
 

[guerra]

Stefan has a drawing, maybe he can upload it, the changes are really simple.

[StefanKrupop]

I attached the basic schematic of the IR-Booster used in China. The used FET is a IRLR3915, the LEDs are HP HSDL4220.
If you want to use the Booster, it is not necessary to fit the IrDA-Transceiver (TFDU4300). Instead, solder Pin 1 of the Booster to Pad 8 and Pin 2 to Pad 3 of the position where the TFDU would have been.

For the future I plan to design a new PCB where the Booster will be integrated with the Transceiver.

Stefan

[StefanKrupop]

As I had to re-build our own IR-Booster, I designed a small PCB for the components. This is not yet integrated with the USB-to-IR-transceiver, but can be easily connected to it (see above).
The connector for DC power is the same as the one for the bot charger.

Have fun!

Stefan

[StefanKrupop]

Warning: The circuit above might have an reliability issue! I am investigating this, but currently I can not reccomend to build it. Maybe I will have to add a level shifter.

Stefan

[StefanKrupop]

Finally I had the time to re-design the USB-IR-Transceiver. The schematic is for big parts the same, but the layout is completely new. It combines the old transceiver, a level-shifter and the booster on one PCB.
I also changed the connections between the FTDI and the TOIM to remove the necessarity to specialy program the FTDI and hopefully make the hardware more stable. This requires small changes to the RobotControl program, I will post a new version soon. The new transceiver has an internal connection that allows the RobotControl program to detect if a V1 or V2 transceiver is connected and initialize it accordingly. This means that the updated program can work with the new and the old hardware without change.

I attached the schematics, board design and updated BOM.

Regards,
Stefan

[StefanKrupop]

As promised, I just posted the changes needed for RobotControl:
http://odin.pcag.fh-wolfenbuettel.de:8080/mixedreality/index.php/topic,106.0.html

Stefan