blu3r4y
Member
Hello! :)
For our diploma thesis we are going to build a Quadrocopter, controlled by WLAN.
At the moment we are searching for a 32-bit development board with WiFi support/WiFi shields.
The wiki (http://leaflabs.com/docs/arduino-compatibility.html#shield-and-device-compatibility) says that the "WiFi Shield" is supported. :)
My question, which WiFi Shield are you talking about? There are so many of them :D
Thank you for your support!
Best regards from Austria,
Mario
Natalie
Member
I use successfully the Wifly shield, based on Roving Network RN131.
Have a look here :
http://forums.leaflabs.com/topic.php?id=999&replies=5#post-7189
(I had to modify the earliest version of "Arduino" library to make it work with the Maple STM32 board).
Some friends of mine and I have done a little work with these modules which is why i asked about working stm code. (see: http://www.wifimidi.com which is our arduino based product)
It has proved less than trivial sometimes however to port arduino code to the maple.
blu3r4y
Member
Woha, thanks guys! Your replies are very useful to me! :)
The MRF24WB0MA WiFi SPI Chip looks very interesting to me, SPI would be very fast and easy.
One last question, did you ever use on of your WiFi Shields / Chips to transmit a huge amount of data? I would like to build up a Live Video Stream. For this usage a reliable data rate of 1-2 Mbps would be required.
If possible, could you tell me your experiences on this?
Regards, Mario
poslathian
LeafLabs
Mario,
You are going to have a tough time getting above 1Mbps. I have done lots of work with various Maple baords linked to the roving networks modules (rn131g or 117). a few quick notes on using that module, which generally works well but:
1) Use an external antenna, seriously, even just one of those foil fractal antennas makes the connection reliability sky rocket. The chiptenna just sucks.
2) Wire up the hardware flow control DTR and CTR. If for whatever reason the connection gets blocked, the FIFO on the wifly chip will fillup, and new bytes will get dropped on the floor and you will never know. The flow control lines will tell you when the FIFO is full. Having bytes drop with no warning pretty much defeats the purpose of TCP!
3) Ostensibly the Maple UARTS can go pretty fast, and support the higher data rates above 115200 that the wifily supports (something above 900000) but whenever I tried those modes I could not get the wifly to talk to me at all any more. I had to do a hard wifly reset, which is a bit of a pain and involves holding some pin high on power up and then toggling another line 5 times slowly (1Hz) to reset to the default 9600 baud.
You should have no problem getting 115200Kbs, and probably faster, but I have never seen that really fast modes work.
x893 I take it thats a no.
blu3r4y the mrf modules will require that you write/port your own stack. On the arduino that would eat half of the memory and a good chunk of the flash. On the arms its not such a big deal.
Most of the serial modules (wifly, gainspan) do most of the tcp/udp and lower layers for you, you pretty much get a couple (8) of streams and a lot of at/escape work to do.
blu3r4y
Member
Hi poslathian,
thanks a lot for your advices on using WiFi modules! I will keep them in mind.
Because of your speed tests, I checked the datasheets of the WiFly RN-171 (http://bit.ly/WiFly-RN-171) and RN-131G/C (http://bit.ly/WiFly-RN-131G).
According to them the RN-131G only supports up to 1 Mbps sustained data rate with UART. With this module it wouldn't be possible to get faster data rates!
However, the RN-171 supports a data rate of 921 Kbps, over UART. And with SPI, up to 2 Mbps.
Most WiFi modules and camera modules with UART only support ~ 1 Mbps at maximum. I think UART can't go any faster! Maybe that's the reason why your WiFi module didn't answer any longer, at such high baud rates?
For our project, the RN-171 WiFi module, connected over fast SPI, would be a nice choice if we really reach the 1-2 Mbps.
At the moment, i have found another WiFi module. WIZnet overs some great serial WiFi modules with "54Mbps data rate and Max.20Mbps Effective Data Transmission". If we only reach a tenth of this 20 Mbps it would be really awesome! :) In their datasheet they also mention "IP cameras" as a possible application example.
Here is the link to the WIZnet610wi module:
http://www.wiznet.co.kr/Sub_Modules/en/product/Product_Detail.asp?cate1=5&cate2=43&cate3=0&pid=1020
Hi feurig,
Phew, that would be a lot of work to write a protocol stack on your own. The memory wouldn't be the problem, we will use a powerful 72 MHz 32bit controller with lots of flash space.
However, it would be great to outsource this task to the WiFi module, so the WiFly, GainSpan or WIZnet module would be a better choice.
Kind regards,
Mario
Mario,
Both wiznet and mouser seem to be out of that. (I have been working with their Ethernet module -- wiz810). Do you have a secret supplier at present?
There is a stack for the mrf for the arduino originally from asynchlabs/now supported by rugged circuits. http://asynclabs.com/wiki/index.php?title=WiShield_library At present however the disparity between arduino/wiring current and libmaple have made porting efforts a little difficult.
Don.
blu3r4y
Member
Hi,
i haven't searched on purpose yet. At present, I have found a supplier in Germany:
http://www.shop.display3000.com/elektronikmodule/ethernet-wlan/wiznet-wiz610wi-wlan-wifi.html
I don't know if this would be an option for you.
Have you ever experimented with huge data rates using the ethernet module from WIZnet? Maybe they use the same serial interface to the microcontroller.
hereiam
Member
@x893: So can I use ZG2100 datasheet from here http://ww1.microchip.com/downloads/en/DeviceDoc/70624A.pdf to create a driver for MRF24WB0MA module?
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