Write code to send an image from a Raspberry Pi Zero to a server with a RockBlock modem

Raspberry Pi

1. Connect the RockBlock modem and insure there is a signal using screen /dev/serial0 19200
   and issuing an AT command, which should reply OK and an AT-CSQ which should return a number > 0

2. Create a virtualenv with python -venv rockblock Once complete, cd into the rockblock directory
   and issue the command . /bin/activate

3. Clone the repo with a the command

   git clone https://github.com/CrabbyPete/rockblock.git`

   This will create new rockblock directy. cd to that directory and issue the following command

   pip install -r requirements.txt

   To upload a file issue the command

   python main.py < name of the file>

   but before doing this make sure the code server.py is running on a server.

Server

The code was tested using pagekite. On the admin page of the device in the Rock7 page
https://rockblock.rock7.com/Operations# Select Deliver Groups. Select the name of the modem
to send the data, select Delivery Address. Enter the address to send it to ( in the test case it was qa.pagekite.me ) and
select HTTP_JSON.

Run the server code with python server.py. If you use this code on a local PC or Mac and use pagekite
make sure the kites are up. (See https://pagekite.net/ for instructions)

Currently the server will create a file called jpeg.jpg. The is the resulting file.

This code can be modified to put the file anywhere or send it to an email address. It can be
converted to an AWS lambda function as well.

Sending a file to the Iridium requires credit and the line rental. The credits can be purchased in blocks of 100. The BEGIN and END message takes 1 credit each. The maximum number of bytes that can be sent in a message is 340. The image is broken into blocks of 340 and sent to the server. Each 340 block of data is 7 credits. A large JPEG file can require over 100 blocks to send the complete image.