Archive for 2016

Look like we are at the end of very eventful year 2016. Lots of twists and turns on the way to reach. Wish you a Very happy new year 2017!

We went through lots of projects and lets have a look at what we have through one by one.

1. RF Udaan

This was project to create a programmable RF platform with LoRa and generic ISM band RF communications. This project has been successful to some extend but still has a learning journey ahead. The project suffered several setbacks due to problems due to the selection of the DRF1276G as a target platform for LoRa. However the ISM band radio using RFM69HW has been quite a success.
Left side of the RFM69HW connected to RF-Udaan board with Pro Mini and DHT22

More closeup view of the Pro Mini board

 These are the RFM69HW board with the base RF-Udaan project board. They work great with simple Wire antenna and have good sensitivity of around -98dB considering the adhoc soldering and wire antenna.

DRF1276G Module connected to RF Udaan board

Little closer look at the DRF1276G
These are the pictures with the DRF1276G module and a Right angle 2dBi rubber duct antenna. They don't perform as good. Possibly due to the RF driver being used or some issues with the hardware. Investigation is still progress.

We have already sent out the next version of this board called RF-Udaan2 as many of you might have guessed. We are migrating the LoRa setup to Microchip's RN2483 module without any further delay.
Also we would be evaluating the RFM95 which many people have recommended. We also have a special surprise design where in the RFM69HW board will become intelligent and will have ESP8266EX connection capability. But that towards 2017, keep a watch.

2. RFM69HW Senor Node

This has now merged into the RF Udaan project as both have similar radio. Just so that you remember by protos:
First Prototype for the RF Sensor Node

Before RF Udaan boards the famous Spider soldering
Presently doing RF Power to battery life evaluation tests. In fact I published some of my initial code for a Low Power execution in a Gist:

This gives an Arduino Sketch where we can check low power consumption of the ATmega328P chip. Though there is problem that it can't be programmed without a ISP programmer. So I converted one of my Arduino to an ArduinoISP and then programed the Pro Mini board from that. But after getting stuck multiple times I used my old trusted Atmel MKII programmer.
So still a working progress. I will update some of my findings that might surprise you. Watchdog in Atmel is great and the Power Shutdown though not very feature rich like the MSP430 is still good. No wonder the ATmega328P is called a Pico-Power chip.

The measure currents are down to 12uA with full memory retention and on-board power hungry LDO on the Pro Min + RF Udaan + RFM69HW board. 

That's a remarkable feet. More on this in the coming posts.

3. Static Site Generator using Golang

Work is progressing on this albeit slower than other projects. Checkout some of my initial examples in the 99_..... directory of the Github repo.

I have now resolved to create a small Thingspeak like service that can be hosted in the local PC or on a simple Raspberry Pi to be able to upload and represent data. Open source web server using golang that can be used to upload data from ESP8266EX. Hope that if you keep checking my play ground repo then you might find some useful pieces of Golang code that you might use for your projects.

4. SIM900 Relay

This project though successful on my side, is still stuck due to non availability of hardware in the location where my friend lives. I have tried to port the library to get it running with the cheap GSM modules but no luck yet. Will be trying to ship some SIM900 boards to solve the problem.

Hope that with renewed spirit in 2017 we would have more projects to discuss and continue where we left off on many others. As always your feedback and support is always welcome.

This is boseji signing out 2016, and see you next time.

Well looks like its late again. About time we should call it a Biweekly update. Sorry about that first stuck with drivers for SX1231 and then lots of soldering on the way.

RFM69HW board, part of RFudaan project - WORKING!!
Also blogger for a change got updated recently. That's interesting, apart from blogger all other things Google have been modernized and made a lot AI.
My project to create a Golang based site generator, still needs to come out of being a paper drawing to a functional Go program. Till then I have to stay with blogger.

I had to do a lot of soldering to come up with the prototypes. Though the boards arrived 2 weeks back I think on 17th or so, it took me quite a while to chop them into pieces.
Thanks to Dangerousprototypes & Dirty PCB team for the great PCBs. Although this time around there were a bit of drill offsets all over. But my thumb rule of 20mil+ annular ring saves the day.

Its late mid week, but had to. Got busy with illness, work and failure. But for the effort invested it was worth the time.
This is a picture of the RFM69HW + Arduino Pro-Mini protype.

Well last week and first part of this week is what I am going to cover here.

Let look at the current running projects:

1. RFM69HW Light Sensor

As you have see above I have tried to make some protos after my successful experiment last week.
Here is the Proto that I had built with Old version of Seeeduino (v2.21) :
The picture is quite dark, sorry for that. Its basically a RFM69HW module soldered on to a general purpose board and then inserted into the Top Right connector of Arduino. And the red wire in front is the antenna. Apparently it broke off twice so I had to finally add some heat glue to fix it.
The best part is using a RTL SDR I could capture the transmission.
868MHz Transmission from RFM69HW - LDR sensor Values

Well of course you would remember one more proto using Arduino Micro:
So now with 3 Nodes transmitting the dance of the frequency spectra is awesome to watch.

Here are some Detailed pictures of the RFM69HW board with Arduino ProMini :

This time I had added an XC6202-3.3V regulator that is used to power the RFM69HW.
Hope that the PCB boards from DirtyPCB comes soon both LoRa and RFM.

2. RF-Udaan project

This is the LoRa board that includes the DRF1276G module. Again waiting to get both the modules as well as the PCB board.

3. Static Site Generator

After getting no where with HUGO, Pelican and Jekyll, I got an idea to write my own. Well that might be a bad idea but a good learning exercise. So some basic work is done on that too. Secretly working with golang since its the fastest and easiest for connectivity. The awesome part its a EXE which is very useful for people like me. I come from hardcore C and Assembly background. So any language that gives net connectivity within 5 lines and give Binary output is great. No framework or Virtual machine needed. Well hope that this would be another good exercise to learn the next generation language.

4. SIM900 Relay

A friend of mine asked me to design a GSM control relay. So I have started working on that too.
Currently using a Arduino UNO and a iComSat SIM900 Shield from iteadstudio.

SMS read was easy to do, now planning to make the interpreter part also.
All code would be posted soon, so watch out.

That would be all for this update, hope to see you next time.
This week lots of testing and RF sniffing. And problems with Windows.
Well my main Laptop gave up, it was Windows 7 Professional 64bit. Though its a beast of a laptop but updates caused a problem. Lenovo asked for an update to BIOS. It was already 00:30 IST and I agreed on installing that. That was all . Next day morning the same laptop stopped booting. After 3 formatting attempts , 2 hardware diagnostics attempts and banging the head 10 times on the wall. I found it was bug in the update of that night. Finally I had got the laptop to boot by disabling some thing called "Execution Prevention and Memory Protection". But by that time the Windows already had gone corrupt on the HDD. So I had to reinstall the complete Windows 7. And to add to the misery Windows Updates on Windows 7 Professional taking eternity to even search. Still waiting on that one.

Fortunately all the current weeks projects are on my PC which is alright. So we are safe to Proceed.
868MHz Transmission from RFM69HW - LDR sensor Values
Well this is an SDR-Sharp Plot of the RF transmission from my RFM69HW based prototype board. The Arduino + RFM69HW Sensor is sending out LDR sensor Raw values to another gateway board connected to the PC. Initially I used the RFM69 driver from Lowpower labs . Later I wrote my own to outdo the adventure.Interestingly the found that 18cm of Wire is an Ideal Antenna for RFM69HW boards. That part was success now working on Signal Reception to formulate a presentation layer protocol above the Raw communications.

Next project RF-udaan is still on track. The boards were already shipped from DirtyPCB. Hope to receive them by this month end (fingers crossed).

Not much progress on the Website porting side. As kept busy with the driver writing work.

Hope to catch up on more this week.
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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