GPIO Tutorial. Modified WorkFlow and Python Code (4 LED)



Hi all,

I modified the original workflow and code to make it work. I removed 1 minute timer and use only interrupt input to switch LED on from LED1 to LED4 one by one.

I think that the original code is toggling LED on/off every 1 minute regardless the timer. When the interrupt button event happens, it checks the timer 1 trigger (it is always false). The original code did not make sense. So, I decided to rewrite the python code to save the last time the interrupt happened.

When a new interrupt occurs, I check the time difference between the previous saved interrupt observed time and the current the interrupt observed time. If the time difference were less than 7sec, my code would ignore the current interrupt event. Otherwise, the code would save the current interrupt’s observed time and turn on the next LED light.

I look forward to read Dan’s detailed post regarding GPIO tutorial. See if I have missed something. I want to post my solution for feedback from any experienced developer. I welcome any comments.



Last Updated: Dec 13, 2016

Author: Medium One


import MQTT
import Store
import Analytics
import DateConversion
import datetime
import Filter
import json

 #  pinmap dictionary allows you to map the physical pin to the logical map address in read_pin/write_pin functions.
pinmap = {'1':0, '8':5, '9':6, '10':7}
waittime = 7

def read_pin(pin, tag):
    send_mqtt_msg(u'0;4;{};{};'.format(pin, tag));

def write_pin(pin, val):
    send_mqtt_msg(u'0;3;{};{};'.format(pin, val));

def send_mqtt_msg(msg):
    mqtt_msg = msg
    if not isinstance(msg, basestring):
        mqtt_msg = ''.join(map(unichr, msg))
    MQTT.publish_event_to_client('s3a7', mqtt_msg, 'latin1')

 # debounce
log ("Detect an input trigger.  It could be a timer or interrupt trigger.")

in1 = IONode.get_input('in1')
log ('The current interrupt (in1) : {0}'.format(in1))
log ('The current interrupt (in1) observed at {0}'.format(DateConversion.to_py_datetime(in1['observed_at'])))

 # Testing purpose only

 # get the previous interrupt time

log ('Retrive the previous interrupt date/time when LED toggles')
    prev_time = DateConversion.to_py_datetime(json.loads(Store.get('intrtime')))   
except (ValueError, TypeError):
    log ('No previous interrupt time.  Assign utc_now datetime as the previous date and time.')
    #prev_time = datetime.datetime.utcnow() - datetime.timedelta(seconds=3)   # guarantee to toggle led
    #prev_time = - datetime.timedelta(seconds=3)   # guarantee to toggle led
    prev_time = DateConversion.to_py_datetime(in1['observed_at']) - datetime.timedelta(seconds=waittime+1)
log('From Store, in1 observed at {0}.'.format(prev_time))

timediff = DateConversion.to_py_datetime(in1['observed_at']) - prev_time
log ("Time Difference between in1(timer1) and last_2_interrupt_events[1] is {0} ".format(timediff))
if DateConversion.to_py_datetime(in1['observed_at']) - prev_time < datetime.timedelta(seconds=waittime):
    log ('Difference in time between the timer trigger and the last interrupt trigger is less than 10 sec.')
    log ('Escape to skip the rest of the code.')
    log ('Proceed to toggle the LED state.')
log ("Execute try")

log ("Store the current interrupt time.")
Store.set_data('intrtime',json.dumps(in1['observed_at']))  # store the time.

    prev_state = int(Store.get('prev_state'))
except (ValueError, TypeError):
    log ("prev_state = None. Initialize prev_state to zero.")
    prev_state = 0
log ("prev_state : {0}".format(prev_state))
 # toggle LED state
next_state = 0

if prev_state == 3: 
    next_state = 0
    next_state = prev_state + 1
write_pin(pinmap['1'], 1 if next_state == 0 else 0 )
write_pin(pinmap['8'], 1 if next_state == 1 else 0 )
write_pin(pinmap['9'], 1 if next_state == 2 else 0 )
write_pin(pinmap['10'], 1 if next_state == 3 else 0 )

 # Not working code.

 #if next_state == 0:
 #	read_pin(pinmap['1'],'GPIO12')
 #elif next_state == 1:
 #	read_pin(pinmap['8'],'GPIO13')
 #elif next_state == 2:
 #	read_pin(pinmap['9'],'GPIO14')
 #elif next_state == 3:
 #	read_pin(pinmap['10'],'GPIO15')
 #    log ("Something wrong.")
 #Store.set_data('prev_state', str(next_state))

SK-S3A7 Tutorials

Wow, thanks for the contribution. I’m going to go through this!

It might be hard for me to go through this today as I’m off to IoT World in the afternoon and I have a meeting with David Thai, the CEO of Medium One in this morning.

What is the module you have next to the BMC 150 accelerometer?


It is a GPS module from Digitlent. It gives me the exact coordination of the IOT board’s location. I plan to use it to get temperature and air quality data in different cities in San Francisco Bay Area.

That may be my next fun project.

Best regards,


Hi all,

Today Renasas support team has kindly been able to provide a valuable feedback to my question about their GPIO tutorial’s Python code. They have confirmed my findings and have updated their python code in their blog. They also said that they want the LED to toggle every 1 minute. It is intentional. So, they want to keep the 1 minute timer which I want to remove as I show my example in this post.

Here are the changes to

  1. Connect raw.interrupt to IN1 of Base Python. So, the LED toggle will occur whenever the interrupt button is pressed.
  2. Leave 1 minute timer alone unconnected. It still can trigger the Python code every 1 minute to toggle the LED.
  3. They agreed to use function call now to get the interrupt event with the observed time stamp. Their old code which used Analytics.last_n_values function will evoke a syntax error.

The above post is very long because I was learning their code and was trying to make sense of it. Hope you don’t mind reading this long post. You can go to the end of the discussion to find their response.

Best regards,