Python loop for posting data to web

[marciokoko]

I got this code for posting data to thingspeak from a raspberry pi (zero):

#!/usr/local/bin/python3 
from envirophat import light, motion, weather, leds
import thingspeak
import time
from datetime import datetime

# Structure of the record - semicolon separated:
# UNIX timestamp;ISO date; light; rgb; motion; heading; temp (celsius); pressure (hPa)

# your ThnkSpeak Channel and API Write Key
channel_id="123"
api_key="456"
thingspeak_data = {}
try:
    now = datetime.now()
    ch = thingspeak.Channel(channel_id, api_key)
    timestamp = round(datetime.timestamp(now))
    cas = now.isoformat()
    leds.off()
    lux = light.light()
    print('%s;%s;%.1f' % (timestamp,cas,lux))
    thingspeak_data['field1'] = cas
    thingspeak_data['field2'] = lux
    response = ch.update(thingspeak_data)
    leds.off()

except KeyboardInterrupt:
    leds.off()

When I run the script from the terminal using the python command it works and posts once of course. But I need it to post every few minutes, so I did this. Replaced try: with while True: and added time.sleep(1800):

#!/usr/local/bin/python3 
from envirophat import light, motion, weather, leds
import thingspeak
import time
from datetime import datetime

# Structure of the record - semicolon separated:
# UNIX timestamp;ISO date; light; rgb; motion; heading; temp (celsius); pressure (hPa)


# your ThnkSpeak Channel and API Write Key
channel_id="123"
api_key="456"
thingspeak_data = {}
#try:
while True:
    now = datetime.now()
    ch = thingspeak.Channel(channel_id, api_key)
    timestamp = round(datetime.timestamp(now))
    cas = now.isoformat()
    leds.off()
    lux = light.light()
    print('%s;%s;%.1f' % (timestamp,cas,lux))
    thingspeak_data['field1'] = cas
    thingspeak_data['field2'] = lux
    response = ch.update(thingspeak_data)
    leds.off()
    time.sleep(1800)

#except KeyboardInterrupt:
#    leds.off()

It works, but only runs a few times and then stops after about the 3rd time. Why?

Mars