The Arduino’s greatest weakness is also it’s greatest triumph. That is, it is only a low power simple processor, which makes internet connectivity for such a simple device difficult. Often the network interface has a few orders of magnitude greater performance than the arduino atmel avr processor itself.
Arduino Yun is the answer to wifi connectivity for arduino. Ushering in a new era known as the internet of things, Yun is actually a complete 400mhz system on chip. There is irony in the fact that the powerful system on chip’s only duty is to serve the lowly AVR. Akin to “You Pass Butter”
Anyhow – today we are going to be looking at some simpler, lower power alternatives to adding wifi to your arduino project. For about 11 bucks you can grab a USR-WIFI232-T from ebay shipped direct from china. And this typically includes an omnidirectional antenna with a U.FL connector! As with most of these Chinese components, who actually manufactures them is murky. I purchased two variants, one from Ebay under the model USR-WIFI232-T (Specs / Mirror) and one from a US distributor Grid Connect under the name and model Hi Flying HF-LPT100 (Specs / Mirror)
These devices provide UART Wifi. This means everything is done over serial. This introduces several limitations such as transfer performance and simultaneous connections. The specs claims capability of 5 simultaneous connections, but in reality they are not 5 separate TCP sessions. All of the connections receive the same data back from the server. This means you can’t have 5 people accessing a web interface each trying to navigate to a different page. Suffice to say – these modules are for simple tasks.
It appears that Hi Flying is the actual developer of this device. As claimed on their website from their own “Highly Cost Effective With High-Flying MCU: MC101”. No matter if it’s Hi Flying or USR, they are all devices based off the Mediatek MT5931 (Specs / Mirror)
Below the MediaTek AC is the High Flying MC101. This is likely a simple ARM CPU. The SDK reveals that this is an arm architecture running FreeRTOS and lwIP. On the reverse of the board is a 16Mbit SPI flash chip from GigaDevice for firmware storage.
For more detail: Arduino Wifi With Hi Flying HF-LPT100 / USR WIFI232-T