Receive USRP data on lopy lora

[nilam]

i tried to receive data from USRP, my code to receive data is
rx_data = s.recv(64)
if(rx_data):
print("Received data: "+str(rx_data))

received data is not in properly decoded
it displays some things like this:

Rx_cnt:12
(rx_timestamp=2217324419, rssi=-78, snr=1.0, sfrx=8, sftx=0, tx_trials=0)
Received data: b'\xbd\xca'
Rx_cnt:13
(rx_timestamp=2218930349, rssi=-79, snr=2.0, sfrx=8, sftx=0, tx_trials=0)
Received data: b'\xc5+*\xfe'
Rx_cnt:14
(rx_timestamp=2219519010, rssi=-75, snr=1.0, sfrx=8, sftx=0, tx_trials=0)
Received data: b'\xe7\xdfl\xfb'
Rx_cnt:15
(rx_timestamp=2220686254, rssi=-84, snr=-0.0, sfrx=8, sftx=0, tx_trials=0)
Received data: b'\xad\xee'
Rx_cnt:16
(rx_timestamp=2221272054, rssi=-77, snr=2.0, sfrx=8, sftx=0, tx_trials=0)
Received data: b'\x95\xe7\xb8\xfa\xf0c\xee'
Rx_cnt:17
(rx_timestamp=2221760271, rssi=-93, snr=-3.0, sfrx=8, sftx=0, tx_trials=0)
how to decode to get hex bytes or string text output

[robert-hh]

@nilam You'll get hex ascii representation with ubinascii.hexlify(), like:

import ubinascii
print("Received data: ", ubinascii.hexlify(rx_data))

I the samples you gave there are almost no printable characters, so displaying it as ASCII is not that useful.

[nilam]

@robert-hh what is the format of received data? like b'\xc5+*\xfe'.
is it utf-8? base64?
Sorry, i am asking very basic .

[robert-hh]

@nilam Python displays it as a mix of hex and ascii. so at
b'\xc5+*\xfe' you have 4 bytes, two of them, + and * are printable. I made a little hexdump function, which translates that to the usual way. It expects an bytes object as input

#
# Hexdump Function
#
FILTER=''.join([(len(repr(chr(x)))==3) and chr(x) or '.' for x in range(256)])

def hexdump(src, length=16):
    N=0; result=''
    while src:  # loop through string
       s,src = src[:length],src[length:]
       hexa = ' '.join(["%02X"%x for x in s])
       s = ''.join([FILTER[s[_]] for _ in range(len(s))])
       result += "%04X   %-*s   %s\n" % (N, length*3, hexa, s)
       N += length
    return result

so hexdump(b'\xc5+*\xfe') returns:

0000   C5 2B 2A FE                                        .+*.\n

As a side note: if you enclose you code with lines, that consist of three backticks (```), it gets printed accodingly

[nilam]

@robert-hh thank you for quick response.

[robert-hh]

@nilam Just to be pedantic, I simplified hexdump a bit. This is old code, collected when I started with Python.

FILTER=''.join([(len(repr(chr(x)))==3) and chr(x) or '.' for x in range(256)])

def hexdump(src, length=16):
    N=0; result=''
    while src:  # loop through string
       s,src = src[:length],src[length:]
       hexa = ' '.join(["%02X"%x for x in s])
       s = ''.join([FILTER[_] for _ in s])
       result += "%04X   %-*s   %s\n" % (N, length*3, hexa, s)
       N += length
    return result

I have my doubts whether I did all of that myself at that time, especially the FILTER= .. expression.