Cheap WiFi modules

[Jumper]

I have what might be a really stupid question.

Is it possible (and if it is then how) to send serial data from one wifi module to an other when they are both connected to the same wifi router?

I would like to remove some cables in a rs-485 network and replace then with uart wifi solution. I just dont know where to start.... well I have a wifi router :-) and the modules and lots of PICs and programmers . Does anyone know?

[richard]

Is it possible (and if it is then how) to send serial data from one wifi module to an other when they are both connected to the same wifi router?

you may not even need a router the esp modules can also act a access point . I have not tried that sort of comms yet but there are examples around on the web using TCP/UDP packets , or you could try TELNET mode . I think telnet is the closest match to what you want

[Jumper]

True, but I need to assign an IP to the module and I can not see any AT command for that ... and I really would like to have static IP so each module always had the same number even when the system is re-booted.

How else do we know who is on the other end of the net?

[richard]

if you do a AT+CIFSR you get two ip addresses the first is the modules ap address the second the dhcp address from your router , question is the first ip address identical on all modules ,maybe they can network that way. " silicon chip" magazine had an article on using these modules as ap's and assigning addresses to other devices using that ap , but I can find no mention of assigning the ap address anywhere . maybe you do need a router , most routers allow permanent address assignments/reservations (usually nested about ten levels deep in some arcane menu structure) .

[gunayburak]

if you do a AT+CIFSR you get two ip addresses the first is the modules ap address the second the dhcp address from your router , question is the first ip address identical on all modules ,maybe they can network that way. " silicon chip" magazine had an article on using these modules as ap's and assigning addresses to other devices using that ap , but I can find no mention of assigning the ap address anywhere . maybe you do need a router , most routers allow permanent address assignments/reservations (usually nested about ten levels deep in some arcane menu structure) .

Hello Richard ...

How did you figure out the pending client problem ... For example if a scenario occurs as follows ; First client connects to the server then the second one connects but its +IPD data will be missed while answering to the first client ... So will its channel number ... Do you have a solution for that ? Or perhaps there is an AT command I can't see that helps us to display the numbers of the channel IDs of the incoming and pending client requests ....

[richard]

How did you figure out the pending client problem

I did not get bullet proof solution with the pic chips I have. they lack sufficient ram but work ok for modest requests
The best solution I have found is to make a queue of ipds to serve
1. serve up your html/cgi page as one unbroken stream (needs heaps of ram) using int driven hardware serial method , note what ipd you have served and remove from queue
2. have a large rx buffer big enough for the biggest request form (about 450 bytes from an android device) this must be back ground int driven method too
3. when not serving , scan rx buffer for new +ipd add to queue
4. the whole process falls to bits if a requesting device asks for a refresh when a request is already pending for that ipd , this I find will lock the esp8266 up or cause it to reset and then lock up (post#50)

I have had much better results with an arduino mega2650 , the faster cpu and 8k of ram makes it easier to do things this way and C 's string functions help too

when I get around to it I will look at tcp/udp methods , its appears to be much more robust

[gunayburak]

I did not get bullet proof solution with the pic chips I have. they lack sufficient ram but work ok for modest requests
The best solution I have found is to make a queue of ipds to serve
1. serve up your html/cgi page as one unbroken stream (needs heaps of ram) using int driven hardware serial method , note what ipd you have served and remove from queue
2. have a large rx buffer big enough for the biggest request form (about 450 bytes from an android device) this must be back ground int driven method too
3. when not serving , scan rx buffer for new +ipd add to queue
4. the whole process falls to bits if a requesting device asks for a refresh when a request is already pending for that ipd , this I find will lock the esp8266 up or cause it to reset and then lock up (post#50)

I have had much better results with an arduino mega2650 , the faster cpu and 8k of ram makes it easier to do things this way and C 's string functions help too

when I get around to it I will look at tcp/udp methods , its appears to be much more robust

Very well ... Here is an another strange problem I keep having with my ESP-01 ... When the ESP disconnects from the WIFI of the router It gets hot (around 41 degrees and so on)... Have you ever had such an interesting problem ?