Raspberry Pi Lights: how to sync Christmas lights to midi audio

The Raspberry Pi and I

** UPDATE 9/21/2014 **

I updated the source code today. Now lightorgan supports more than 7 output channels.  It chooses the pin to light up based on both the pitch and the octave of every note. Now the number of supported output channels is limited only by how dynamic the range of the midi file is. I observed that this worked practically for at least 24 channels on several Christmas songs. This is cool because the new Rasperry Pi Model B now supports up to 28 pins!  See Gordon’s page at http://www.wiringpi.com.

Also, the WiringPi pins that lightorgan uses are now configurable. Just modify the array called pinMapping[] that’s near the top of the lightorgan.c file to add, remove, or remap a lightorgan channel to a corresponding WiringPi  pin. Recompile with your changes and then you should be good to go.

Check out the new source code from the google…

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Backup & Restore Your Logstash/Grafana Dashboards

Web Development Insights

<TLDR>
I created a Chef cookbook with which you can backup and restore your Logstash/Grafana dashboards. You can find it here.
</TLDR>

It wouldn’t be an exaggeration to say that Logstash and Grafana have changed my life. I can’t even remember how I was monitoring or investigating performance issues before having them. When I first installed those tools and started to feed them with data I was really excited by the possibilities they offered me. Building dashboards was so easy and fluid. Create a widget, select the data to display and viola – you have a neat looking graph! With time I added more and more dashboards both to Logstash and Grafana. I now have dozens in each. They show me everything I need to know and when I find they have a missing piece – I add it right away.

A sample Grafana dashboard A sample Grafana dashboard

Everything went well, life…

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Why We Chose Kubernetes Over ECS

Web Development Insights

On our last post, we saw how Docker changed the way we treat our infrastructure and what changes it brought to the domain of service orchestration.
In the following post, we’re going to take a tour of two of the leading Docker orchestration frameworks out there: ECS (Elastic Container Service) by AWS, and Kubernetes, an orchestration framework which began at Google and became open source later.

3 months ago when we, at nanit.com, came to evaluate which Docker orchestration framework to use, we gave ECS the first priority. We were already familiar with AWS services, and since we already had our whole infrastructure there, it was the default choice. After testing the service for a while we had the feeling it was not mature enough and missing some key features we needed (more on that later), so we went to test another orchestration framework: Kubernetes. We were glad to discover that…

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Apache Spark Cluster Internals: How spark jobs will be computed by the spark cluster

Knoldus

In this blog we are explain how the spark cluster compute the jobs. Spark jobs are collection of stages and stages are collection of tasks. So before the deep dive first we see the spark cluster architecture.

cluster-overview

In the above cluster we can see the driver program it is a main program of our spark program, driver program is running on the master node of the spark cluster.

Cluster manager is the responsible for allocating resources for the given job.

And worker nodes have a executers in which the task will be running and stored the data in the cache.

This is Apache Spark basic architecture of the cluster.

Now we discuss about different RDD types created on transformations as follows:

  • HadoopRDD
  • FilteredRDD
  • ShuffleRDD

HadoopRDD: Spark make a RDD from the Hadoop InputFormat so it makes a new HadoopRDD and map the partitions with Hadoop block size by default…

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