You need to wait at least 1/8000002460=1.8 milliseconds after you call set_color before calling the next one. It’s safer to double it. When BlinkStick is sending data to the LEDs, it can’t respond to USB requests. The math is as follows:
- 800000 is the speed in bytes/second at which data is transmitted to LEDs
- 24 is the amount of data that needs to be transmitted to each LED, 8 bytes per each channel
- 60 is the amount of LEDs you are controlling
Your script should look something like this:
#!/usr/bin/python
#Import blinkstick module
from blinkstick import blinkstick
import time
#Find the first BlinkStick
bstick = blinkstick.find_first()
counter = 0
while counter < 60:
bstick.set_color(channel=0, index=counter, name="black")
time.sleep(0.003) #<----- You need to add this to wait for black color to be sent to the LEDs
counter = counter+1
bstick.set_color(channel=0, index=counter, name="green")
time.sleep(0.2)
This actually adds a slight delay when LED is turned off before the next one is turned on. To avoid this, you need to send LED frames, which means that you are sending all LED data at once. I’ve created a BlinkStickPro class for this specific reason. There is a very nice RGB analogue clock example you can find in the wiki which is using this class.
The steps include:
- create a subclass of blinkstick.BlinkStickPro
- in the initialization, you can specify delay parameter which defaults to 0.002. You also have to specify how many LEDs are connected to each channel.
- set_color function will not send data to the device, instead it will store the color data in the internal buffer.
- when you have all colors set and ready to send to BlinkStick, you need to call send_data_all. It will automatically send the whole LED data at once to the BlinkStick and then wait the amount of time specified in the delay
- then you can prepare the next frame of data and send it again to the device
The code example to utilize this looks like this (I haven’t tested though 
) :
import time
from blinkstick import blinkstick
class Main(blinkstick.BlinkStickPro):
def run(self):
self.off() # sets all LEDs to black and send the data
try:
index = 0
while (True):
self.clear() # sets all LEDs to black internally
self.set_color(0, index, 255, 0, 0) #this only sets the color on internal buffer
#you can add more lines here to control LEDs
self.send_data_all() #sends the data to BlinkStick Pro
index = index + 1
if (index == 61):
index = 0
except KeyboardInterrupt:
self.off()
return
main = Main(r_led_count=60, delay=0.004)
if main.connect():
print "Press any key to exit..."
main.run()
else:
print "No BlinkSticks found"
print "exit"
Hope this helps
