Hello i just want to get an Idea how to send a file to ESP32 (Arduino)
All similar Topics said its not possible.
My Situation:
File is a Binary (Update.bin) for ESP32 Firmware update
File Size: ~700KBytes
And i want to transfer it via BLE (String?)
I did all that the other Way around: Sending Logfiles (Log.txt) as a String from ESP32 via BLE to APP
Files are arround 160KBytes and the Speed is 15KByte/Sec
But with ESP32 i can Split the Logfiles in 500Byte Buffer. With App i just save everything received to File.
This should work the other Way around.
But how can i read files and split them in 500Byte packets?
Is it possible with 700KByte Files?
Assuming you have enough RAM to hold the entire file on the ESP32 side, I imagine that it's possible although given the packet-based nature of BLE you'll probably want to include both an index as to what chunk you're sending as well as a checksum at the end so you can ensure that the firmware image didn't get corrupted. The real challenge I think you're going to have is that the built-in App Inventor File component really only handles files as text. There may be extensions that would allow you to read the file as binary and manipulate it as such for sending the data to the peripheral.
i did some test to read the .bin file and send it with BLE to ESP32
but...
problem: i cant spilt the file text to BLE compatible packet size
with segment text i cant spilt the text, but it counts in readable Chars. So split from 50 to 100 results in over 100 chars (50 readable and 50 unreadable) that are send with BLE
but this works....the right Bytes are send to ESP32. But i cant really produce correct buffers
problem. i tried to convert the text to list and send the list via BLE. But i cant convert string to Number (write bytes) -> show error
and with WriteString i just get 4 bytes
i know your example, but i never found out why you are using the Base64 encoding?
i checked my files with a hex viewer and they are similar.
But there are some errors (i have to find why) and the calculated transmission time is 25min!
Thats too much. So i have to wait for a new Version of the BLE Extension which can send 512 Bytes with one BLE Packet.
From ESP32 to APP i can already send 512 BYtes and its much faster to transmit it the other direction
app inventor reads the file an put every byte in the list and tells me List Lenght is 256 -> correct
on ESP32 i get these 256 Bytes
But just 0x00 to 0x7F are correct
Here the output:
0 1 2 3 4 5 6 7 8 9 A B C D E F 10 11 12 13 14 15
16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A 2B
2C 2D 2E 2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F 40 41
42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57
58 59 5A 5B 5C 5D 5E 5F 60 61 62 63 64 65 66 67 68 69 6A 6B 6C 6D
6E 6F 70 71 72 73 74 75 76 77 78 79 7A 7B 7C 7D 7E 7F EF BF BD EF
EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF
EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF
EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF
EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF
EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF
EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF BF BD EF
i did some research on Base64 and now i'am understanding why Juan use it and why my binary date is not transmitted correctly.
i will do some more tests.....but at the moment i will stop it because the BLE connection with 20 Bytes per Packet is much to slow. I have to wait for the supporting of MTU Size packet lenght.
