Color transfer with EnviroPHAT and UnicornPHAT


#1

To test the new Enviro PHAT color sensor, i though i could couple it with the Unicorn-PHAT with its RGB-LEDs.

You need:

  • 2 Raspberry Pi (i tested with two pi zero)
  • Enviro PHAT
  • Unicorn PHAT

Install the needed libraries, put both Raspberry Pi on a network.

Script for the Unicorn-PHAT Raspberry Pi (server side):

import SocketServer

import unicornhat as u
u.set_layout(u.PHAT)

def set_color(r, g, b):
    for x, y in [divmod(i, 4) for i in xrange(32)]:
        u.set_pixel(x, y, int(r), int(g), int(b))
    u.show()


class ColorHandler(SocketServer.BaseRequestHandler):
    def handle(self):
        try:
            data = self.request[0].strip()
        r, g, b = data.split(",")
        set_color(r, g, b)
    except Exception, e:
        print "Bullshit received!", e

server = SocketServer.UDPServer(("0", 2000), ColorHandler)
server.serve_forever()

Code on the Enviro-PHAT Raspberry Pi (client):

import envirophat as e
import time, socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM);sock.connect(("server-hostname-or-ip", 2000))
while True:
    time.sleep(0.1)
    sock.sendall("{0},{1},{2}\n".format(*e.light.rgb()))
sock.close()

Now try some light of different colors on the Enviro-PHAT and see the unicorn PHAT illuminate in that color.

Note that the code is very simple, you should not catch all Exceptions without proper handling on the server side and provide some reaonable socket closing on the client side (like catching KeyboardInterrupt). But it works for basic testing of both hats.


#2

Very nice! I particularly like your error catch message!


#3

For a more sophisticated implementation you may want TCPServer and StreamRequestHandler, but i had some issues with disconnected sockets and to keep it simple (i.e. almost no error handling) i just switched to udp.

I did not manage to transfer a blinking bike rear light, i guess either the sensor or the led switching just isn’t fast enough.