File Transfer using OpenMV WiFi shield

I’m new to openmv.
I’ve been looking at the WiFi examples and am wondering what protocol options I have for sending image frames to a server or cloud service.
Encryption would be nice but not a must have.
ftplib isn’t available.
Any help appreciated.

Hi, we don’t have any streaming protocol implemented, we just send M-JPEG over HTTP.

Ok. I have file transfer going but neither zlib or binasii modules supplied include crc32…
Given the this MCU has hardware CRC support, could this be added at sometime.
I cobbled together a crc32 calculation that uses a lookup table but this causes an memory allocation exception.

def create_table():
a =
for i in range(256):
k = i
for j in range(8):
if k & 1:
k ^= 0x1db710640
k >>= 1
a.append(k) <------ Crashes Here
return a

def crc_update(buf, crc):
crc ^= 0xffffffff
for k in buf:
crc = (crc >> 8) ^ crc_table[(crc & 0xff) ^ k]
return crc ^ 0xffffffff

def GetCRC32(filename):
f = open (filename, “rb”)
l =
crc = crc_update(l,0)
while (l):
l =
crc = crc_update(l,crc)
return crc
crc_table = create_table()

x = GetCRC32(‘042217_09142018.mjpeg’)


Can you repost your code with the code tags. You’re likely overflowing the heap which gets fragmented. A way to fix this is to import the gc module, explicitly delete unused variables, and call gc.collect() before your method.

Please submit a feature request to github.