Instructables

Raspberry Pi (security) Slow Scan Television Camera

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For project updates, visit: AgriVision - Raspberry Pi SSTV Camera.

The goal of this project is to use the Raspberry Pi with the PiCam as a wireless camera which can transmit images over long distances, usually tenths of kilometers. Images will be transmitted by amateur radio (ham-radio) using slow scan television (SSTV) on the 2 meter band (144.5 MHz).

Since the Pi can generate the HF FM signal itself, no additional electronics are needed for low power transmissions. For a little bit more power a one or two transistor amplifier will be suitable. Furthermore a low pass filter is recommended to filter out higher harmonics of the signal.

This project also contains a python script which detects movement. Using this script the Raspberry Pi can be used as a wireless security cam at distances far outside the range of normal WiFi networks.

Be aware that you need a ham-radio license to use this application!

Here is a video of the camera in action:

 
 
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Step 1: Capturing the image

First thing to do is capturing the image we want to transmit. This can easily be done with raspistill:

raspistill -t 1 --width 320 --height 256 -e png -o /tmp/image.png   

For sstv we need a small image, of 320 x 256, it is saved into the /tmp directory as png.

phinch2 months ago

wow this is great.

I'm hoping to implement your version of pifm and a usb gps dongle into a aprs beacon. you have inspired me, but I don't know if I have the programing skills.

73

CMGMatt2 months ago

I'm using your custom code but I'm getting a 'Segmentation fault' error? How do I fix this?

Cheers

CMGMatt CMGMatt2 months ago

I'm an idiot... Fixed it. I tried to use another image...

SugarCluster6 months ago

Alternatively we can use walkie-talkie pair with shared band(channel) to use this without getting arrested by FCC.

(Or,a FM-band low power transmitter that doesn't interfere with commercial radiowaves)

11428 months ago

Thanks for sharing. I have been snooping around for something similar ever since PiFM was announced. This was a great step by step guide. The steps were easy to follow and and I even took the step to mod. the text color in sstvcatch.py to yellow for better contrast.

73!

AbDuCt8 months ago

Does the image get screwed over if there is any noise on the frequency? Some of my friends were playing with tcp/ip over ax.25 and some jerk was broadcasting over us and all the packets would become currupted.

soldeerridder (author)  AbDuCt8 months ago

depends on the signal strength, strongest signal wins, the same as with WiFi or other wireless techniques. You can increase your signal strength by using more power, or better use directional antenna's with high gain on both the receive and transmit side.