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High speed UDP, full duplex

PostPosted: Thu Jan 07, 2016 11:41 pm
by logicx
greetings.

I am trying to figure out something but i have found nothing relating to it so i hope maybe someone here will know.

I have a wifi based gestural system that consists of 3 wifi stations and an access point. I have been doing this with 3 rn-xv trancievers attached to arduino fios. connecting to a standard wireless router over wifi. it is an open source project i am preparing to release but the cost of the fios and the rn-xv's makes it prohibitively expensive (approximately $175 for 3 fios and 3 rn-xvs, not including batteries sensors, etc.) this is the project https://i.ytimg.com/vi/xOUFublvNUk/maxresdefault.jpg I decided to shift everything over to the esp8266's because they are more powerful and seem to be far more programmable and cut the cost of building a system down to a total cost of about $65 (in additon to using chinese accelrometers and raw atmega 328p IC's.

the way i use wifi is simply to use UDP to blast the firmata formatted serial data to the computer, running pure data , process it, then blast back LED control data to the in the body worn system. the total amount of data is about 200kb per unit. i use a flush timer to clear the buffer every 5ms at a 115200bps baud rate i am still hoping that i can discover (with your help) how to use the ESP-01's i have, to replicate this somehow. basically a data dump from the arduino over udp and then a dump from the computer back to the arduino as fast as the components can handle.

I also have an esp-12 that i want to use as the access point to replace the wireless router so the whole system can be used with raspberry pi's and worn. this piece is the last part of the puzzle. i "think" th access point should be pretty easy and the rpi's are all ready to go as well. any insight would allow me to have the project ready for a youth workshop i am preparing for in a couple of weeks where i hope to share the joy of programming with kids here in detroit. in exchange, i will be sure to post the updated project here as soon as it works. :-) this is the system in action with the previous components https://www.youtube.com/watch?v=RNx9mHlBcqo (the new system is 95% 3d printed, including printed sensors)

cheers!

Re: High speed UDP, full duplex

PostPosted: Fri Jan 08, 2016 10:29 pm
by logicx
it just occured to me that i may be able to use 2 ESP's as one, ie, one for transmitting to the computer/router and one for recieving from the computer/router, per unit-left hand, right hand, mouth unit. all 6 ESP's still cost less than 1/3 of the cost of an 1 rn-xv, and with one for tx and one for rx, there will be no bottlenecks. this also might double my IO meaning that i can use the esp-01's and the arduino for sensor input into the computer/router and then use the rx esp's (esp-12's) pwm pins to control the leds ! the only drawback i can see is battery useage. 500ma is alot of juice to be pulling, but i can always swap the batteries out need be.

unless someone has a bettter suggestion, im gonna wire this up and see what happens. seems like it might be even better than single esp's for the same task!

Re: High speed UDP, full duplex

PostPosted: Sun Jan 10, 2016 3:25 am
by logicx
is full duplex not possible?

Re: High speed UDP, full duplex

PostPosted: Mon Jan 11, 2016 4:45 pm
by lethe
logicx wrote:is full duplex not possible?

Wifi is half-duplex only, no matter which hardware you are using. In fact most RF protocols are half-duplex, unless they are using different frequencies for RX & TX.
Using 2 ESPs, you will not give you any advantage either, since the AP assigns timeslots for transmission to each client.