Raspberry Pi video controller

This is a video server running on a raspberry Pi Linux computer. It provides a web interface to stream and record video.

What it does

• Arm - Start video recording when a TTL is received. Hook up the ScanImage frame clock to the Pi and this will start a video recording at the start of each stack or timeseries.
• Record - Record a one time video.
• Stream - Stream the video to your web browser so you can see a live feed.
• Stop - Stop any video streaming or recording.
• IR On/Off - Turn one set of LEDs on/off. The brightness of the LED is set with the slider. This is usually hooked up to a bank of IR LEDs.
• White On/Off - Turn one set of LEDs on/off (usually hooked up to White LEDs)
• Message - Text entered in the ‘Messages’ field are saved to a text file with timestamps.
• Provides real-time feedback with elements/objects within the webpage updated without reloading. Some examples are: the time of day, the last ScanImage frame number, current log file, temperature, humidity, etc.

Interface

How it works

The server is pure python running on the Pi. It uses the web framework Flask. Once the web page is loaded by a client browser(you), any objects within the webpage can be updated in real-time using flask-socket-io. This can be done without refreshing the entire webpage. The layout and interface objects are using Bootstrap.

Required Hardware

• Raspberry Pi
• Raspberry Pi Camera, the IR version is called ‘NOIR’.

Installation:

• [I need to make a GitHub repository with the python source code]
• [I need to write out how I install this, my original and pretty useless notes are here]

Running the server

sudo python iosserver.py

This will tell you the IP adress you use to login to the server.

Connecting to the server

Just point any browser to the server address.

http://192.168.1.60:5000

Extra Details

The internet of things

Python code running on any other internet-connected device can ‘inject’ values into the iosserver and they will show up in real-time inside all client browsers. Here is example code on another Pi that has its own temperature and humidity sensor.

# send to iosserver
import requests
try:
	payload = {'timestamp': thisTimestamp, 'insideTemp': temp, 'insideHum': hum, 'outsideTemp' : outsidetemp, 'outsideHum' : outsidehumidity}
	r=requests.get('http://192.168.1.60:5000/_add_numbers', params=payload)
	print 'sent to 192.168.1.60 !!!'
	print payload
except:
	print '-------- error sending to iosserver ---------'

The iosserver receives this GET request with a little function decorator.

@app.route('/_add_numbers')
def add_numbers():
    timestamp = request.args.get('timestamp', '') # defaults to ''
    insideTemp = request.args.get('insideTemp', '')
    insideHum = request.args.get('insideHum', '')
    outsideTemp = request.args.get('outsideTemp', '')
    outsideHum = request.args.get('outsideHum', '')
    print 'timestamp=', timestamp
    # myVideo is another python class that handles all runtime
    # it is not detailed in this example
    myVideo.insideTemp = timestamp + ' ' + insideTemp
    myVideo.insideHum = insideHum
    myVideo.outsideTemp = outsideTemp
    myVideo.outsideHum = outsideHum
    print 'add_nummbers() received ', timestamp, ' ', insideTemp, ' ', insideHum, ' ', outsideTemp, ' ', outsideHum
    return ''

There are a few more steps including some javascript and html. This is not a Flask or Socket-IO tutorial. Have a look a socket-io for Flask.