How to do simple TCP communication betwenn PC and ESP?

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DK3GR
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Joined: Mon Aug 09, 2021 11:49 pm

How to do simple TCP communication betwenn PC and ESP?

Post by DK3GR »

Hi,
what commands and syntax must be used for simple TCP send and receive data between
PC and ESP?
cicciocb
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Re: How to do simple TCP communication betwenn PC and ESP?

Post by cicciocb »

Hi DK3GR,
this is a minimalist example based on the use of PowerBasic and Annex.
PowerBasic has the capability to establish TCP connections so it is quite easy to use it with Annex.

The exchange is done using the event [Local Link Removed for Guests] and the variables are exchanged using the format var1=10&var2=20&var3=30&....

This example simply send 3 variables and returns the sum of their value.

Hoping this is clear for you.

Annex Code

Code: [Local Link Removed for Guests]

' Annex controlled by powerbasic http demo
OnUrlMessage received
wait

received:
wlog UrlMsgGet$()
a = val( UrlMsgGet$("a"))
b = val( UrlMsgGet$("b"))
c = val( UrlMsgGet$("c"))
UrlMsgReturn "The sum is  " + str$(a+b+c)
return 
PowerBasic Code

Code: [Local Link Removed for Guests]

' PowerBasic example with Annex
' send variables and receive the content
#COMPILE EXE

FUNCTION PBMAIN() AS LONG
  LOCAL Buffer$, Site$, Arg$

  Site$ = "192.168.1.12"            ' IP address of the module
  Arg$ = "/msg?a=123&b=200&c=300"   ' variables sent to Annex

  ' Connecting...
  TCP OPEN "http" AT Site$ AS #1 TIMEOUT 1000 ' maybe increase a little bit

  ' Could we connect to site?
  IF ERR THEN
      BEEP
      EXIT FUNCTION
  END IF

  ' Send the GET request...
  TCP PRINT #1, "GET " & Arg$ & " HTTP/1.1"
  TCP PRINT #1, "Host: " + Site$
  TCP PRINT #1, "User-Agent: Annex"
  TCP PRINT #1, "Connection: close"
  TCP PRINT #1, ""

  ' Send and retreive the message

  TCP RECV #1, 4096, Buffer$
  #DEBUG PRINT Buffer$
  ' extract the result after a double CR LF
  ret_msg$ = MID$(Buffer$, INSTR(Buffer$, $CRLF + $CRLF) + 4)

  MSGBOX ret_msg$

  ' Close the TCP/IP port...
  TCP CLOSE #1
END FUNCTION
DK3GR
Posts: 2
Joined: Mon Aug 09, 2021 11:49 pm

Re: How to do simple TCP communication betwenn PC and ESP?

Post by DK3GR »

Hi ciciocb,

now i am happy and here is the result of my work:

Code: [Local Link Removed for Guests]

LEDpin=33
pin.mode LEDpin, output
FLASHpin=4
pin.mode FLASHpin, output
pin(FLASHpin)=0

print
print
toggle 3

MIN_SPACE   = 100000                        'take pictures only if some space is left on flash or SD-card


wifi.connect "xx","xxxxxxxxxxx"             ' ypur wifi access
print "connecting ";
While WIFI.STATUS <> 3
  Print ".";
  pause 500
  wend
print
print "connected, ";
wmode=wifi.mode
if wmode=0 then print "wifi sleep moce"
if wmode=1 then print "wifi station mode"
if wmode=2 then print "wifi AP mode"
pause 2000
print
print ip$
print

rf=ramfree
ff=flashfree

print "RAM   free:",rf
print "Flash free:",ff
print

ret=bas.device
print "Basic device:",ret
'if bas.device=202 then print "ESP32CAM detected"

OnUrlMessage received
'wait
z=0
do
  z=z+1
  option.wdtreset                             ' reset watchdog timer
  loop
end

received:
wlog UrlMsgGet$()
a$=urlmsgget$("a")
print a$

r$=a$
kw$=ucase$(mid$(a$,1,3))
arg1$=mid$(a$,5,4)
arg2$=mid$(a$,10,4)
arg3$=mid$(a$,15,4)
arg1=val("&H"+arg1$)
arg2=val("&H"+arg2$)
arg3=val("&H"+arg3$)

if kw$="VER" then cmdVER        ' VERsion
if kw$="RST" then cmdRST        ' ReSeT

if kw$="CSU" then cmdCSU        ' Camera SetUp
if kw$="FLH" then cmdFLH        ' FLasH on/off

UrlMsgReturn r$
return


sub cmdVER
  res1=1:res2=2:res3=3:n$="0000":n=0
  hx res1
  r1$=n$
  hx res2
  r2$=n$
  hx res3
  r3$=n$
  r$="VER"+" "+r1$+" "+r2$+" "+r3$
  end sub

sub cmdRST
  res1=1:res2=2:res3=3:n$="0000":n=0
  hx res1
  r1$=n$
  hx res2
  r2$=n$
  hx res3
  r3$=n$
  r$="RST"+" "+r1$+" "+r2$+" "+r3$
  reboot
  end sub

sub hx(n)
  n$=hex$(n)
  n$="0000"+n$
  n$=right$(n$,4)
  end sub

sub LEDon(LEDpin)
  pin(LEDpin)=0
  end sub

sub LEDoff(LEDpin)
  pin(LEDpin)=1
  end sub

sub toggle(n)
  local i
  print "Toggle ";n
  LEDoff LEDpin
  pause 1000
  for i=1 to n
    pause 300
    LEDon LEDpin
    pause 300
    LEDoff LEDpin
    next i
  end sub


sub cmdFLH                                ' cmd flash
  res1=1:res2=2:res3=3:n$="0000":n=0      ' setup default result
  hx res1
  r1$=n$                                  ' result 1
  hx res2
  r2$=n$                                  ' result 2
  hx res3
  r3$=n$                                  ' result 3
  if arg1=0 then                          ' check arguments
    pin(FLASHpin)=0                       ' do the job
    else
    pin(FLASHpin)=1
    end if
  r$="FLH"+" "+r1$+" "+r2$+" "+r3$        ' setup return string
  end sub

sub cmdCSU                                    ' cmd camera setup
  res1=1:res2=2:res3=3:n$="0000":n=0          ' setup default result
  hx res1
  r1$=n$                                      ' result 1
  hx res2
  r2$=n$                                      ' result 2
  hx res3
  r3$=n$                                      ' result 3

  option.wdt  10000                           'watchdog timer 10seconds
  wifi.power  20                              'maximize wifi-power

  ' variables with CAM parameters
  quality     = 10   : brightness  = 0
  contrast    = 0    : saturation  = 0
  awb         = 1    : awb_gain    = 1
  wb_mode     = 0    : aec         = 0
  aec2        = 1    : ae_level    = 0
  agc         = 0    : agc_gain    = 0
  gainceiling = 0

  ret = camera.params("quality", quality)
  ret = camera.params("brightness", brightness)
  ret = camera.params("contrast", contrast)
  ret = camera.params("saturation", saturation)
  ret = camera.params("awb", awb)
  ret = camera.params("awb_gain", awb_gain)
  ret = camera.params("wb_mode", wb_mode)
  ret = camera.params("aec", aec)
  ret = camera.params("aec2", aec2)
  ret = camera.params("ae_level", ae_level)
  ret = camera.params("agc", agc)
  ret = camera.params("agc_gain", agc_gain)
  ret = camera.params("gainceiling", gainceiling)


  option.wdtreset                             ' reset watchdog timer
  if flashfree <  MIN_SPACE then              ' check memory
    print "NO SPACE FOR FOTO!"
  else
    print "make Foto"
  endif

  ret=CAMERA.PICTURE("/PIC.jpg")         ' set framesize
  print

  hx ret
  r1$=n$
  r$="FLH"+" "+r1$+" "+r2$+" "+r3$        ' setup return string
  end sub

There are two minor problems:

1. To stop the programm i have to press the STOP butten in the IDE followed by
a reconnect. Then i must press again the STOP butten and the monitor will
answer "program finished". Why not on first STOP? Is this normal?

2. The responce time fpr this bidirctional HTTP communication is not very fast.
The TCP communication on my other modules with TCP commands is faster.
But at the moment i think it is fast enough.

For the next steps i will add:

1. commands for READ, WRITE and CLEAR EEprom.

2. Add data for mini windows on the captured picture (pos x,y, size x,y)
with 6? items.

3. Compare mini window pixels with the next captured pic and detect movement
of a modell locomotive. The result will be continous polled by the Host PC.
For example: On movement in square window 50,100,30,30 lok must stop

If this job is done, one camera for just 10 dollar can control a complete
central station. The Metallus Radio Train System (MRTS) is much cheaper
and has more possibiltys than the slow uncertain communnication over the tracks.

Thank you very much for your qualified and fast help!
cicciocb
Site Admin
Posts: 401
Joined: Mon Feb 03, 2020 1:15 pm
Location: Toulouse
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Re: How to do simple TCP communication betwenn PC and ESP?

Post by cicciocb »

Hi,
Happy to hear that it worked for you.
About the "stop", I don't know.
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