Jpeg image view using Bluetooth

[Samson_W]

Hi ,

I'm new to creating app and I though this is the best way to build an app for my project . I have arduino which can take pictures using arducam . I need to build an app to view the image .

As first step I manage to search for Bluetooth and connect to the device using an example .

I add another to button to cake snapshot ;

next step to accept image data and show the image (this is the part that i'm having issues with )
I read some comments online and used image block convert to base64 and view the jpeg image but It didn't work as expected .

Appreciate if someone can help me to sort this problem or guide me with a proper solution .

Thanks in advance .

[Juan_Antonio]

Try this

Bluetooth HC-06 Send/Receive image.jpg file to/from Arduino. SdCard Reader. Text file

1.- App converts an image: pozo_4.jpg to string Base64 by an extension. The string is sent by Bluetooth HC-06 to Arduino. Arduino receives the string, converts it into the file pozo_4.txt and saves it in a micro SdCard. p9L2_Bluetooth_Base64_2.aia (78.7 KB) Asterik * for end_of_send You can try with pozo_4kB, pozo_20kB and pozo_50kB [base64i_13] Arduino UNO, BluetoothHC06 module, SdCard reader and microSdCard: [sdcard4b] Micro SdCard Reader search image. Code Arduino. #include <SD.h>…

[Samson_W]

Thanks Juan for your response ,in my case instead of sending as a text to the app the camera sends the jpeg data in binary format ,so will I be able to still use this method?

[Juan_Antonio]

@Samson_W

this method

Give it a try, this method converts a file to String Base64 and sends that String. Try small files < 80Kb first.

Bluetooth HC-06 Send/Receive image.jpg file to/from Arduino. SdCard Reader. Text file

2.- Arduino sends pozo_4.txt to App by Bluetooth HC-06. App receives this string Base64 and converts it to file: /mnt/sdcard/el_pozo.jpg Image component shows that image. p9L2_Bluetooth_Base64_3.aia (89.4 KB) pozo_4.txt (5.2 KB) [base64i_14] When btn_receive click, App sends character "k" to Arduino, then reception will start. When App receives the asterisk * (code 42), it will interpret that the reception has finished. Extension will convert the received string to /el_pozo.jpg. …

[Samson_W]

Thanks, ill give it a try .

[Samson_W]

Hi @Juan_Antonio ,

I tried the method you provided. It seems that you need to save the base64 data to a JPG file and then retrieve it to display the image on the phone.

In my case, I want to decode the base64 image data (which is captured from Arducam and converted to a base64 string) and display it right away. I tried connecting the received string block directly to the .base64toImage block as shown below:

However, it's giving me a runtime error "bad base-64". When I use list view to display the received data, I can see the whole frame received as a base64 string. So, I'm not exactly sure why the error occurs.

I also tried copying a base64 JPEG frame from camera and pasting it into a text box to see if it displays the image properly, and that works:

My question is, for the incoming string data, do we still need to copy the JPEG frame as a base64 string to a file in order to display the image? Or is there a way to decode it right away and show the JPEG image (Similar method as showed in the first image ?

Appreciate your help.
Thanks, Samson.

[Juan_Antonio]

BLE sends 24-byte packets.

https://community.appinventor.mit.edu/t/ble-esp32-bluetooth-send-receive-arduino-ide-multitouch/1980

https://community.appinventor.mit.edu/t/send-file-via-ble-to-esp32/26883/8

[Samson_W]

Thank you for the prompt response @Juan_Antonio , is there a method or example that can append all the received bytes in that frame and send to decode ? Instead of saving in to a file and decode to file to an image ?

Thanks.

[Samson_W]

Seems like this method works ,

Thanks.