Archive for October 2016

First of All :
Best wishes to all the readers and friends...

Well this week too even though a festive week, so work was achieved. Starting with the two main projects that are currently in progress:

1. RFM69HW Light Sensor:

Well this one got way ahead. I got to understand that RFM69HW has a Semtech Chip SX1231H which gives the +20dBm power capability. Tried out the Arduino RF69 driver from Lowpower labs. Still not happy with the performance and features available. Lot more info about this library is available on their website with better description of the packet structure. One more difficulty with this driver was that its written for the Mortino boards only so had to hack internals of the library. And after playing around with all that I got the insatiable urge that every geek knows of. Well I want to write my OWN LIB.
Bad luck radios are hard but it would be nice learning experience for me. All these days I have design RF hardware but could not venture into radio firmware. So just started to tinker around with the RFM69HW and its internals. I have made some headway in understanding the Frequency calculation for this radio module. That part and some insight would be for another post later. But watch out I will take this out and soon.

2. ESP-udaan board now RF-udaan (! Sorry !)

Well you might wonder what the heck one more name change. Well thats what developers and makers struggle with. For hardware engineers its : Naming things and Unlearning concepts.
You  might have guessed it right. ESP8266 has unfortunately removed from this board.
Well now this board has 2 Modules - RFM69HW (ISM) and DRF1276G (LoRa)
Additionally in the remaining space there is an Adapter for Arduino Pro Mini that would be used to control these boards. Also added are a DHT22 and LDR for sensing interface to Arduino board.
I placed the order with DirtyPCB service from Dangerous prototypes. I had used their service previously and was quite satisfied by the quality. Only problem it take more than 30days to get the boards some times !! Hope that it arrives in time before TheThingsNetwork deploy LoRa Gateways around Bangaluru.

Well there is more......
I could not just sit around so I started another project :

Static Site Generator

Well its in progress and its one thing I have been wanting to do for a long time. Blogger has become too unwelcoming. Its old and my idea was to move away from it. So I had already selected a few famous ones.

Evaluating all three of them , Not sure of Ruby so jekyll is ruled out.
Both Golang and Python are my favorites hence they are fighting each other in terms of features and easy implementation.
Once I have a successful theme even a bare minimum I will make a move to a per-created github website URI. Should leave the old for RIP.

That's all for this week, check out more next week.
This week was pretty hectic with lots of things going on. However there were two main projects that a currently progressing:
  1. LoRa + RFM Board
  2. RFM69 Light Sensor
LoRa RFM Board
RFM69 Light Sensor

 Well about the LoRa RFM board ( bad name sorry ! )  this one is a long time though Idea. I wanted to have an Arduino enabled LoRa board. Then I had need to work with RFM modules from HopeRF. So I combined all the requirements together + added our favorite ESP8266 into it. Then came the ESP-Udaan project. So now on this board would be called ESP-Udaan not the weird long name. The board is designed such that one can program an Arduino Pro Mini or the ESP8266 as needed. Plus the would be flexibility to expand using the edge connectors. I have also provided one small I2C connector at the bottom of the board to connect the DS3231 Raspberry Pi modules for RTC. That would make this into a good IoT node. Watch out next week for some more updates.

Next, the RFM69HW Light sensor. This is an attempt to build an out door light sensor using RFM69HW and an Arduino Nano clone. I am using a 868MHz module since that's whats legal in Bharat(India). This would gradually make the framework for the ESP-Udaan board. Since that too has the same profile. Added to the bread board crooked wiring is a TLV-2217-3.3V Texas Instruments LDO. As I wanted to have good power available so connected the RAW output of the Arduino Nano (means the USB input power) to this regulator generating 3.3V. The Tranceiver powered up comfortably and got response back. The software is still work in progress.

That would be all for this week checkout the build progress next week and more.

Its already been 2 years since I last posted.
You might already be noticing the change, and  in what way this blog will be written in future.
From now on the blog will have only myself @boseji and no more the team.

We started around 2009 a team of 8 people committed to create good content on the net about Electronics, Embedded, Linux, Physics and various other outlandish ideas. However eventually in the course of time everyone except myself dropped out.

Most people might have seen only my credentials on the blog as the final publication was only done by me. The team was suppose to create the content and hence the term "We" was used in most cases. The content for maximum cases was being compiled by @boseji and reviewed by others. It was a constant wish of everyone to get their name on the blog. That was possibly the point of departure. Unless someone brings about original content, spend hours in actually typing and proof reading the articles; they are just can't post it. No one realized that hard work that goes into doing so.
Well that might be me complaining about them.

I still kept going for the next 5 years till 2013 and then I became quite busy at work.
All contacts started dropping out since then. Even though the contributions were scanty from the team, there used to be little innovation call-ups and new product ideas. All of that came to a screeching halt. And there was silence afterwards.

It was after a lot of persuasion and recommendations of the followers still on this blog & family, that I am taking the baton again.
Even though it might be only me, I will try to keep my promise again and keep moving forward.

Thank you dear readers & friends for all your support.
We had been silent on our adventures with the latest Android version Lollipop. So here is it, the most simple and easy to follow build instructions for compiling Android Lollipop from source starting from scratch (bare minimum Ubuntu 14.04 PC with Internet and above 40GB usage remaining).

Its been long that this post has been in Draft  about 2 years so Lets go ahead and complete this.
All credit goes to :

Here are the Compilation commands:

>repo init -u -b android-5.1.0_r1 

>repo sync -j4  
>sudo apt-get install openjdk-7-jdk 

>sudo apt-get install bison g++-multilib git gperf libxml2-utils make zlib1g-dev:i386 zip 

>sudo nano /etc/udev/rules.d/51-android.rules 

>javac -version 
Should be Open JDK 7

>sudo update-alternatives --config java 

>. build/ 

You're building on Linux  Lunch menu... pick a combo:      
1. aosp_arm-eng      
2. aosp_arm64-eng      
3. aosp_mips-eng      
4. aosp_mips64-eng      
5. aosp_x86-eng      
6. aosp_x86_64-eng      
7. aosp_flo-userdebug     
8. full_fugu-userdebug      
9. aosp_fugu-userdebug      
10. aosp_deb-userdebug      
11. aosp_tilapia-userdebug      
12. aosp_grouper-userdebug      
13. aosp_hammerhead-userdebug      
14. aosp_mako-userdebug      
15. aosp_flounder-userdebug      
16. m_e_arm-userdebug      
17. mini_emulator_x86-userdebug      
18. mini_emulator_x86_64-userdebug      
19. mini_emulator_arm64-userdebug      
20. mini_emulator_mips-userdebug      
21. aosp_shamu-userdebug      
22. aosp_manta-userdebug  Which would you like? [aosp_arm-eng]    

Selected  12. aosp_grouper-userdebug  for Nexus 7 2012 tablet


>make -j4 

Takes 2hours 30minutes on Quad Core operation

This time its become much Simpler and easier to compile. No need to too many complex installations.

As promised this time we would be discussing further on the Backup Power Domain and special Shutoff Mode EM4. Initially we looked at how the EFM32 can be transitions to various power states. However "there is more to this chip than that meets the eye".

The EM4 mode of this chip is way more configurable and can be very useful. Its only that we need to take some system design considerations into account before using this mode.
Let us review the conditions of the peripherals for this mode:

---- This was a 2 years old incomplete post
It looks like that EM4 is very difficult to plot with the power analyzer. I had abandon that.
Sorry folks that would be all.

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