image transfer from phone to nrf52840

[karthikeyan]

hi team,

     i need a clarification. my expectation is i want to transfer a image from mobile to nrf52840 pdk and display that image to the gui interfaced in pdk. my doubs are.

1. can i interface the gui in pdk. if yes is there any starting guide or support or how can i start.

2. is there any open source mobile app to transfer the image from mobile to pdk. so that i can check whether it is working or not. if there is no app can you give me the suggestion how can i achieve.

i am using sdk 14.1. 

[Jørgen Holmefjord]

Hi,

1. What kind of GUI are you talking about? I assume you are talking about some display interface, but I cannot give you any great answer without more details of the interface. In general you can interface most SPI/I2C/UART devices using our nRF52840. For display interfacing, we have a GFX library and drivers for two displays (ST7735R and ILI9341) in the SDK. There is also an example showing how to use it.
2. I'm not aware of any such applications, but we do have one that transfer an image from the DK to the phone. The principle should be the same, you just need to send the image the other way.

Best regards,
Jørgen

[Jørgen Holmefjord]

I'm not familiar with hologram technology. Could you post links to details about this techonology, or some specific parts you are planning to use? If it can be interfaced using one of the serial interfaces supported by nRF52840, I don't see any reason you should not be able to implement this. 

[Jørgen Holmefjord]

From the video, it looks like you simply want to display a normal 2D video that will light up on the plastic device showing the video from different angles. I don't see any issues with displaying video on the screen, it is only fast updated images. 

If you need high update ratest on the display, you can use the high-speed (32 MHz) SPI interface on the nRF52840, but make sure you use a display that support this rate. I2C will most likely not have high enough speed for displaying video. Storing such large files will also require you to have some fast external memory for storage. The QSPI interface is ideal for this purpose. Note that if you are planning to transfer 100 MB over BLE, this will take some time. Even with the 2 Mbit high-speed mode released in BT 5.0 specifications, the maximum transfer speed is about 1350 kbps, which means the transfer of 100 MB will take at around 74 seconds at under ideal conditions.

We do not have any examples specific for showing video, but this should not be any different than showing images or text, you just need to update the display more often.

[karthikeyan]

yes i understand jorgen. any ideas about which display can i use. and i asked about do i want save the video in external memory and start display it or can i use my controller as a throughput mediator without saving the video.

[Jørgen Holmefjord]

I do not have any display recommendations beyond the ones we have in the SDK. This will depend on your requirements on resolution, refresh frequency, etc. If you can pass the incoming data directly to the display controller, depends on the size and bitrate of the data. The nRF52840 is limted to 256 kB ram, and 1 MB flash. Writing to flash is slow, and not possible with high BLE activity. If you need more buffer than what is available in RAM, you will have to store it to an external memory.

[karthikeyan]

ok thankyou jorgen, with this conversation i will go ahead to make my project. if i find any difficult in that i will contact for help please assist.

[Jørgen Holmefjord]

Good luck!