Networking, Protocols, and Devices
Topic: RN-XV Latency?
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Dec 26, 2012, 01:51 am
Apologies if this has been asked before.
I recently threw together a simple HTTP remote control sketch that relied on a cheap Ethernet shield I had kicking around (ENC28J60-based.) I never thought to time it but the response times must've been in the sub-200ms range.
The area I want to put my remote in has no convenient ethernet and I figured it'd be better to go with an arduino-controlled wireless shield/module rather than stick it behind a wireless access point. Since it was the cheapest option I went with an RN-XV - https://www.sparkfun.com/products/10822
...let's skip over the part where I swear at pull-up resistors, firmware, and many other things...
All is well and I've got the WiFlyHQ library wired up and handling basic HTTP. However, I'm getting ~0.7sec round trip times...I've poked around a bit and I can't find any real answers.
I'm using an Arduino UNO R3, a SeeedStudio XBee Shield (with a 10k pullup between vcc and din), and the RN-XV I linked above with the latest firmware from RN - 2.50.
It looks like the issue is related to the WiFly not closing client-initiated TCP connections - as near as I can tell it's taking me about ~100ms for my sketch to hand off a final (less than 256 byte) response to the WiFly over serial.
Anyone with experience on this one? Should I just give up, write my own transfer format, and stick a HTTP->that proxy on my desktop?