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Monday, November 28, 2011

WolframAlpha FM Synthesizer

This is a nice way to simulate the modulation effects.
From http://codehop.com/wolframalpha-fm-synthesizer/

Economic Shift Register interfacing

We came across an interesting technique of interfacing Shift Registers. We all know that the Shift Registers need 3 I/O lines to interface at minimum.
However if we can cleverly time  the Load and Clocking pulses to get the job done:
The above circuit times the PL pulse of the 74HC165 with the Clock pulse. It uses the limit of the CMOS threshold levels in 74HC14.
Even more interesting is that if this could be done over a single I/O line by alternately configuring it as an input or output.
For Detailed info Refer:

Friday, November 25, 2011

Compiling mspdebug for Windows using MinGW

We were trying to compile the windows version of Mspdebug from its source.
In this post we would detail the dependencies that needed to be taken care off and how to make the Mspdebug-0.18 build with MinGW.

First let us browse the setup:
1. We need Latest version of the MinGW installed presently using :gcc version 4.6.1 (GCC)
2. Download the Old Regex utility from GNU http://ftp.gnu.org/old-gnu/regex/ file regex-0.12.tar.gz

3. Download the Mspdebug-0.18 http://sourceforge.net/projects/mspdebug/files/mspdebug-0.18.tar.gz/download
Note: Make sure that MinGW in in the path along with Msys for the binutils

Building the Dependency of the regex in MinGW
1. Extract the regex-0.12.tar.gz file in a directory say regex-0.12
2. Compile the files: gcc -g -DHAVE_STRING_H=1 -I. -c regex.c
3. Now make the lib file: ar ru libregex.a regex.o
4. Copy the files to the respective directories:
libregex.a => [MinGW dir]\lib and regex.h => [MinGW dir]\include
Here are some quick commands:

cp libregex.a ..\MinGw\lib 
cp regex.h ..\MinGW\include
Thanks to kemovitra blog for help.

Also possible to Get the more recent(2007) Regex Package mingw-libgnurx-2.5.1:

File modifications for including LibUsb-Win32 used in MinGW:
1. Need to change #include<usb.h> to: #include <lusb0_usb.h>

2. Each of the following files need to be modified:
mspdebug-0.18\util\usbutil.h      Line number: 22
mspdebug-0.18\drivers\olimex.c Line number: 23
mspdebug-0.18\drivers\rf2500.c Line number: 22
mspdebug-0.18\drivers\ti3410.c Line number: 23

Compiling the  Mspdebug:
1. Use the command:  make WITHOUT_READLINE=1
2. If this works then you have a mspdebug.exe ready !!
Next we need to try out using this to program the MSP430 chips.

Saturday, November 12, 2011

MSP430F5310 Breakout

We recently developed our first MSP430F53XX breakout board. This board was targeted for developing advanced applications on MSP430.
We have hosted this project as an Open Source Hardware project on Github.

Here is a preview of the schematics:
This board can be programmed using the TI LaunchPad also.

We would be revising this to make a Booster Pack for the TI LaunchPad.

Sunday, November 6, 2011

Removal of old Serial Port entries and COM port Re-assignment in Windows

Many time we have see that we are stuck with some odd serial port Numbers such as COM58, COM86 and all. We were bugged up with this issue as we have several Bluetooth dongles and each creates it own set of 10 COM ports!
To make matters worse when the 2-digit COM numbers is exhausted then 3-digit code like COM103 or COM112 are listed. Most of the Serial port terminal programs support only 2-digit code. And if you happen to have some old piece of software that expect the COM to be a single digit one like COM3 or COM9 then you hit the road block.
This problem has happened to us several times. We found some quick workaround to fix this. The platform being Windows XP Professional in consideration, but should work for Windows 7 also.
Here are the steps to achieve this:
  1.  Open Regedit :
    • From Start Menu click on Run and then type regedit in the text provided
    • Make sure you are logged in as Administrator in Windows XP else in Windows 7 it would ask for Administrator permission.
  2. Navigate to the Key:
    HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Control/COM Name Arbiter
    • Looks something like this:
      Regedit Window showing the CommDB option
    • Now Right click on CommDB and click on Modify..
    • This will show a window like this:
    • The Value of the CommDB would be some thing like COMDB = FC FF FF 03... or some thing similar. Now this indicates the number of ports occupied in binary. Each bit represents a COM port slot being occupied.
      For Example if you have COM1 , COM2 and COM4
      then COMDB = 0B 00 00... in => Binary (0000)u (1011)l = (0D) hex
    • So accordingly first calculate the value of the COM ports that you have on your PC at all times and cleat off rest of the bits.
    • For our case we have COM3 at all times representing the built-in Modem so our value would be Binary (0000)u (0100)l = (04) hex
    • Here is the modified window:
    • Note: Make sure you dont add additional bytes to this entry or it would cause System Crash
    • This completes the second step
  3. Navigate to the Key:
    • Here you can see all the COM ports currently present or are plugged into the computer
    • For our case we don't have any other ports than the Modem so here is how it looks like:
    • If you need first uninstall the ports from pc and check if they are update here.
  4. Navigate to the Key:
    HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Windows NT/CurrentVersion/Ports
    • Here you would be able to see all the assigned COM ports available
    • This is how it would look like:
    • Delete the COM ports that you don't need. For Example we needed only COM3 rest all COM port entries can be deleted.
    • Make sure you dont delete any other ports else System Crash
  5. Now reboot the PC
Now when ever you plug in the new hardware if it shows the old port then just uninstall the driver and plug it back again. It should get a new port assigned.

For more info Read the following:

Wednesday, November 2, 2011

TI Unleashed the Revolution (Palm Sized) - BeagleBone

BeagleBone is a new development board from TI in the BeagleBoard Series. This brings nearly the same power of the other Beagleboards right into palm of your hand.
This board contains the AM335x Family of Sitara Arm(r) Cortex-A8 processor.
Here are some vitals about this board:

  • Board size: 3.4" x 2.1"
  • Processor: 720MHz AM3358 Family of Sitara Arm(r) Cortex-A8 processor
    Link: http://www.ti.com/am335x (Ref Manual)
  • Memory: 256-MB DDR2 RAM
  • USB: 1-port USB 2.0 host, 1-Port USB Debug + Serial Terminal using FT2232
    Single cable development environment with built-in FTDI-based serial/JTAG and on-board hub to give the same cable simultaneous access to a USB device port on the target processor
  • Ethernet: Integrated 10/100 Ethernet
    On-chip Ethernet, not off of USB
  • Expantion: 3.3-V 2× 46-pin peripheral with multiplexed LCD signals and battery-control expansion headers. Industry standard 3.3V I/Os on the expansion headers with easy-to-use 0.1" spacing
  • Shipped with 2GB microSD card with the Angstrom Distribution with node.js and Cloud9 IDE
  • Easier to clone thanks to larger pitch on BGA devices (0.8mm vs. 0.4mm), no package-on-package memories, standard DDR2 vs. LPDDR, integrated USB PHYs and more.

Have a look the the Current Beagleboard Flyer to compare with the other boards.
If you are wondering where to plug in the display then worry not there is a DVI-D board that gives the DVI monitor port and the audio connections.
Here is a video that show it all:
We can wait to grab of these - Hope it would be same for you too :-)

Wednesday, October 26, 2011

Happy Deepawali 2011

We would like to wish you a Prosperous, & Happiness filled Deepawali(दीपावली).

Thursday, October 20, 2011

Remove Trace of USB Devices plugged into a PC

We found a little piece of software that could help to remove the trace of USB devices such as Pen Drives, Flash Disks, or your custom hardware. We were trying to check the USB driver installation of one of our projects. However we had to manually remove its presence by deleting registry keys. Sometimes if the wrong key deleted the whole Virtual systems would crash. So we were in trouble.
Well NirSoft’s USBDeview helped us out of this trouble.

This is a free utility that you can download from http://www.nirsoft.net/utils/usb_devices_view.html

Note: In order to make sure you can uninstall the devices you need to run this program in the Administration logon.

Flying Saucers: Superconductor Magic

We came across this innovative video showing the Magnetic Levitation using super cooled materials.This demonstrates Quantum Trapping phenomenon in super conductors at low temperatures.

Thursday, September 22, 2011

Android on X86: We have Google's Power

We were overjoyed to hear that Intel x86 can now run Android. That would mean the Host and Targets can some day have the same platform for development. This is Great news!!
Here is the link to the Project page:

Here are the Official Intel Website giving the Instructions to installing Android on x86:

Here is the Video of Android Running on Intel N450 based Systems:
This is the Link: http://edc.intel.com/Video-Player.aspx?id=3778
If you wish you too can buy these boards here:
Intel Atom Dev Kits Link

Let us know if you get some of them..

Monday, September 12, 2011

Small is IN:Single molecule is tiniest electric motor ever

There has been a remarkable advancement in performing Molecular arrangements which pave way for useful NanoElectronics in the Future. Here is what we came across recently:

The smallest motor ever made and that's why its contesting in the Guinness World Records.
Molecules have previously converted energy from light and chemical reactions into directed motion like rolling or flapping. Electricity has also set an oxygen molecule spinning randomly. But controlled, electrically-driven motion – necessary for a device to be classed as a motor – had not yet been observed in a single molecule.
To address this, E. Charles Sykes at Tufts University in Boston and colleagues turned to asymmetric butyl methyl sulphide, a sulphur atom with a chain of four carbons on one side and a lone carbon atom on the other. They anchored the molecule to a copper surface via the sulphur atom, producing a lopsided, horizontal "propeller" that is free to rotate about the vertical copper-sulphur bond
Catch it @NewScientist 

Audioino: Arduino programmable via sound card

Here’s a unique way to program an Arduino chip: using your computer’s sound card! Chris from the hobby-roboter forum provides the details on this amazing hack in his forum post.The process simply requires the Atmega168 to be programmed with Chris’ special audio bootloader. The whole project requires only the addition of three resistors, two caps, an LED, audio jack and reset switch. Thereafter programs are developed in the Arduino IDE, then the hex is uploaded to the Audioino via Chris’ Java program (contained in the source code zipped file.)This is a really cool hack, reminding some of us how we loaded programs into the CPU memory using cassette recorders back in the day.
via DangerousPrototypes.com

Sunday, September 4, 2011

New PCB's from Seeedstudio's Fusion Service

We were trying out new sources to get some PCB's from. SeeedStudio provides an innovative and cost effective PCB making service called the Fusion Service. We have now evaluated this service for our MSP430 boards. The quality of PCB was really good for the price.

There are several size options also available(5cm x 5cm & 10cm x 10cm are our most used.
For Bharteya(Indian) Comparison here are the General prices that we have seen:
a. 5cm x 5cm PCB Double Sided
        Local Vendors: INR1050    (3-5 Quantity & Only One Side Silkscreen)
       SeeedStudio:     INR667.2   (Including Shipping , 10QuantityBoth Sides Silkscreen)
b. 10cm x 10cm PCB Double Sided
        Local Vendors: INR1520     (3 Qunatity & Only One Side Silkscreen)
        SeeedStudio:    INR1334.4  (10 Quantity, Including Shipping & Both Side Silkscreen)

In all we are very Happy with the Service & PCB from SeeedStudio and we thank them for this wonderful quality service

We are going for another round of PCBs and hoping that we get them soon.

Friday, August 5, 2011

MinGW: Made Easier

We had initially covered a tutorial to Install MinGW environment. Now the installation has become even easier with the Automated MinGW Installer . This is a single executable file that needs to be downloaded and it would take you through the entire process.

Here are the links:
> Source for the Automated Installer:
> Good Introduction to the Instal process
&gt: Our Tutorial & Articles on MinGW

Tuesday, July 19, 2011

Inflatable Antenna from GATR

We came across the remarkable innovation that makes it possible to have remote stalactite communication and still has portable infrastructure. GATR Technologies has developed an antenna that can fit right into your backpack.
This is an inflatable 1.2-metre satellite antenna that can fit into a backpack and be carried by a single person. It is a double-layered sphere with one layer a nylon mesh and the other made from sail material. The antenna is in the centre. The receiving dish divides the sphere's interior into two chambers and by applying pressure to one chamber you can push the antenna into a parabolic shape. The company already sells a larger, 2-metre version but this one is small enough to fit in an airline's hand luggage area when folded.

For Further info have a look at the following links:

Monday, July 11, 2011

MMA8453Q Accelerometer Breakout - Update

We had built the MMA8453Q accelerometer breakout board. We could not test it since long.
For the Circuit we followed what the Datasheet said:

We only had to map it to our pin Configuration as stated earlier.
For testing we used the Famous Buspirate from Dangerous Prototypes.

We wish to Thank Dangerous Prototypes for creating such a nice tool.

Here is a picture of what we were working:

And here is the Command Sequence:

1. HiZ
2. 1-WIRE
4. I2C
5. SPI
10. LCD
(1) >4
Mode selected
Set speed:
 1. ~50KHz
 2. ~100KHz
 3. ~400KHz
(1) >1
I2C>[ 0x3A 0x0B 0x01 ][ 0x3A 0x0B 0x01 ]
I2C>[ 0x3A 0x0D [ 0x3B R ][ 0x3A 0x0D [ 0x3B R ]
As you see in the Last Lines it prints 0x3A which is the "who am I" kind of address for MMA8453Q.
Note: SA0 is High so the Write address is 0x3A and Read Address is 0x3B

Here is the Commands that were sent:
1. Wakeup command: [ 0x3A 0x0B 0x01 ]
2. Read the "Who am I register" : [ 0x3A 0x0D [ 0x3B R ]

So the Accelerometer is working and now we can conceal the chip package in glue to make it into a robust chip form factor. Next on the list is using it in an actual application.

We would post more updates on that soon. Let us know your comments.

Friday, July 1, 2011

Scripting Android(SL4A) with Python on LG Optimux P500

We got our first Android Phone LG Optimus P500 with Android 2.2 Version. This phone has 512MB of internal RAM which is good to give a decent performance. We did not limit us to this, we wanted to make some good use of this mobile. So the Idea came that we can try to have a programming environment right int the Android Phone.
We knew that there is a complete development environment available to use PC as the host and develop applications for Android. But we wanted some thing easier. Something that could help us get Python on Mobile.
We found Scripting Layer for Android brings scripting languages to Android. SL4A in short.

Scripting Layer for Android (SL4A) brings scripting languages to Android by allowing you to edit and execute scripts and interactive interpreters directly on the Android device. These scripts have access to many of the APIs available to full-fledged Android applications, but with a greatly simplified interface that makes it easy to get things done.
Scripts can be run interactively in a terminal, in the background, or via Locale. Python, Perl, JRuby, Lua, BeanShell, JavaScript, Tcl, and shell are currently supported, and we're planning to add more. See the SL4A Video Help playlist on YouTube for various demonstrations of SL4A's features.
We wanted Python so we went for Py4A - Python for Android.
This is the version of Python that's built to Run with the SL4A and includes various functionality such as Blue-tooth Encryption etc.

Here is a list of files that you need to download:
sl4a_r4.apk: The SL4A Frontend

textedit-sl4a.apk: Editor for the scripts

PythonForAndroid_r5.apk: Python Interpreter for SL4A (Or the latest version available)

Python Modules:



Now after you have all these files in the Phone in a separate Directory say "/sdcard/Develop/"
You are ready to go for the Installation.

Steps for Install:
- Install the sl4a_r4.apk File (Make sure you have install from Unknown source option enabled in settings)
- Install the textedit-sl4a.apk and PythonForAndroid_r5.apk
- After this transfer the SL4A and TextEdit applications to SD card from settings
- Open the Python for Android App and click on Install
   (The App would now download the nessary files automatically. So make sure you have your internet connection ON in the mobile)
- After the Extraction is done it would show that the installation has been successful, Now click on Import Modules and sequentially install the modules one after another. (All three of them)
- Exit the Python for Android App and then run the SL4A app to get the SL4A Frontend running.
  (Dont miss this else like in the Video the programs wont run)
- Now go back to Home screen keeping the SL4A running in background - Run the Text Edit App
- Browse the SD Card for "sl4a" folder in which the "scripts" directory contains the "HelloWorld.py"
   (should be "/sdcard/sl4a/scripts")
- Now you can edit the file and save it
- Go back to Home screen and Open the SL4A app again. Click the Option button to refresh the files
- Single click on the HelloWorld.py shows the activity bar. (this contains the "Terminal Run" or "Edit" Options)
- Click on the Terminal icon to Run the Modified HelloWorld.py
- You see a terminal window automatically pop out and then says "Hello World"
- Now you would be prompted to Exit the Terminal so click "Yes
That's It - You have successfully executed your first Python Script on Mobile.

Here is the Video that Demonstrates all procedures after the Files are Downloaded:

Saturday, June 25, 2011

MMA8453Q Accelerometer Breakout - Soldering can be Art

Check out the Update: MMA8453Q Accelerometer Breakout - Update

Well we have been busy all this time so you see not much of blog activity. However our pursuit on creativity continues.
We were trying out the Freescale's new Accelerometer MMA8453Q which we procured recently.
The problem with this chip was that it was a QFN-16 package and so tiny that we did not believe it could be soldered in any way even if we get a PCB done.
So, so... This was a job for the Wiring Pen we described earlier.

We first soldered the Chip to a piece of veroboard using FeviQuik (conventional Cyanoacrylate adhesive).
Picture of the Chip glued on to the veroboard
Bottom view of the chip showing pin descriptions

Then we did the fine art work of wires using the Wiring Pen and made a breakout.

Breakout pin configuration
We have tested this out and its working!!

As requested here are steps that can help you build your own QFN breakout:
[1] Invert the chip and fix it onto a small piece of Vero board as shown in the First Picture above.
You can use the Cynoacrilate Adhesives (like Fevi-quick we have in Bharat) for this purpose.
But be careful they are extremely poisonous and you can hurt your self it fall any where other than desired.
[2] Identify the Pin 1 location and the desired pin configuration as shown in the Bottom View picture of the chip. Then map it to the desired breakout you would like to have as showing the Breakout Pin configuration picture above.
[3] Solder the Berg pins carefully in the breakout positions as decide in the mapping.
[4] Apply the No-Clean flux on the bottom of the chip and the pins.
[5] Take the Wiring Pen and tin the tip of the wire with fresh solder uncovering the insulation. The length of the uncovered insulation to be as small as possible.
[6] Carefully take a minute ball of solder on the soldering Iron tip and attach this wire to the pin
[7] Next measure the distance to the Berg pin by taking the Wiring Pen near to it so that the wire automatically unrolls. Now cut the wire to be soldered on the berg pin.
[8] Tin this end of the Wire which we just obtained using fresh solder and then fix it the berg pin soldered point by applying the soldering iron and inserting the wire into the solder. This makes your first pin ready.
[9] Using a pain of Pins as probes measure the continuity for this connection in the multi-meter. It should be as low possible but dont press the pins hard else they might damage the joints.
[10] Not continue the steps from step [4] for all the pins you need to take out.
[11] Once done clean the entire thing in a small bath of IsopropileAlcohol to ward off all the unwanted flux or the resin residue from the solder wire.

Thats all for the process.
Thanks for your interest. Let us know your feedback in case you would like a Video demonstration.

Check out the Update: MMA8453Q Accelerometer Breakout - Update

Friday, May 20, 2011

Quick Response Code: Details

We always wondered what and how the QR code came into play. This remained a shady fact that we used it couple of times on the mobile phone for URI catching but never got to find the real designs behind the screen.
Until Recently we found this:
Source: Wikipedia
In fact the QR Code is covered by a Patent 6,494,375 from Denso Wave.
We found even more detailed picture:
Source: QRME
The data contained in the QR Code is an amazing 4,296 Characters of text or 7,089 Digits or simply 2,953 Bytes. This means a complete HEX file for a small microcontroller can be embedded into one QR Code. Or think even better. A whole Letter that you send on a page can converted into a few QR Code Symbols !!
Many of the Mobiles and App sources such Google App Store Zxing provide API that help to encode data in QR Code format.
We are hoping to utilize this technology and cover the easy to implement QR Code in many of our projects.
Scan for your self....

For more Details Visit:
Wikipedia Article on QR Code:
QRME Website for more Documentation on QR Code:

Thursday, May 19, 2011

MSP430 JTAG & Spy-By-Wire Connections

Some time people mistake the connections for the common MSP430 debug interfaces. Specifically in our new board we ran into some issues. So here are some pictures to help you.
Spy-By-Wire Connection

Jtag Connection
Hope that this would help.

Tuesday, May 17, 2011

Wiring Pen: For next gen in DIY prototyping

We came across ELM chaN's website and wondered at how soldering can be an Art.
Source: ELM chaN Website
In hopes to be able to make this possible, we read through the entire tutorial on Wiring Pen & how UEW (polyUrethane Enameled copper Wire) is used.
Looking at this we wanted to make our own Wiring Pen so we started in search of the raw materials:

[1] UEW: We found an easily available source from Mobile repair Shop. On the website we found indication to using the old Relay Coils or any type of solenoid etc. We found this:
In Bharat its available in any Mobile Repair Shop for others they can take it from an old relay. The best part is that you get a bobbin free if you take it out of the Relay.

[2] Syringe Needle & Pen: This is need for planning the exit of the wire in the Wiring Pen. You can get it from any of the medical shops. Also you would need an transparent Pen for use as the body. So here is a picture of what we have collected so far.
[3] Screw: This is needed to fit the Bobbin to the Pen Body.

Now here is how you Assemble the whole thing:
[1] Fix the Nail to the body of the Pen:
[2] Have a Stopper made out of a Plastic container lid to keep the bobbin in place. We have used a Screw on the Other end also. This was made possible by the use of a Metal Stud in the Center as you can see from the above picture.
[3] We added an additional (pulley using a) paper clip insered into the pen at the end of the pen to help the wire be pulled smoothly without damage.
[4] Next carefully insert the wire through the pen body and out on the other side. Then insert it into the Syringe and the Pen Tip. Here we found that initially that the syringe Needle had a big back projection and it could not fit into the pen. So we cut that out and adjusted it to fit in to the Pen's tip. We also inserted a small filler to tighten the Needle.
After Assembly:
[5] Now put every thing together and you have the Wiring Pen Ready !!
Our Wiring Pen is Ready !!
Hope that you liked our build, let us know your comments.

For more information visit the following Links:

ELM chaN's Website:

Tutorial on How to build a wiring Pen:

Sunday, May 15, 2011

Sneak Preview: MSP430 Dev Board

We were into the development of an MSP430 board for our Projects. This was the reason we were a bit late in posting. Here are a few pics to help you get an idea:

This hardware would be a completely OSHW compliant would be hosted on our website. We are also planning to make kits to be sold in order to raise money for our new ventures and projects.
So keep watching and this would be out soon ...

Thursday, May 5, 2011

MSP430 with FRAM: Break Through in Microcontroller World

We received an Astounding news that TI has been successful able to combine FRAM Technology into one of the world Lowest power microcontroller MSP430. We knew about the verifiability of FRAM earlier but combining it with the Microcontrollers adds a whole new dimension to it.
Source: TI Website
Some of the unique Capabilities are:

  • Lowest Power Writes
  • Virtually infinite Wrtie Cycles
  • Adjustable barrier between Flash and the RAM as both can be the same
  • Complete Data retention at much lower power
  • High speeds of Read & Write - the example in the Video was really neat
  • Radiation Hardened & Extra long Data Retention - Terminator Style !!

The initial category of the Devices: MSP430FRXX
Contains ADC, UART, I2C with the normal set of Timers & Clock structure
Presently Samples of MSP430FR5739 are available. However these would be first engineering samples.

There is also a promotional MSP-EXP430FR5739 Experimenter Board which is available at $29 from TI e-Shop with free Shipping.
Source: TI Website
This board contains a 3Axis Accelerometer, NTC Thermistor, 8 LEDs and two push buttons. With on board debugging link like that of Launch Pad this is value for money.
We would wait and watch out for all innovations around this platform, till then for more info Visit:

Open Source Hardware Logo Usage

We got a few picture and templates for using the OSHW logo.However we wanted to make the Logo on PCB and various other things that we keep making. So we found some good Source:

Here we got the following to use for the Logo:
SVG Format OSHW Logo
So the Size of the Logo can be independent can easily be used in Inkscape.

This was nice we can now use it in documentation also.

For all PCB Cad tools also many people have already contributed:

gEDA platform

Eagle platform
This is basically an ULP that can be run or customized to make the logo in Eagle PCB.

KiCAD platform

For more information view the following links:

Long live OSHW!!

Saturday, April 30, 2011

LM3914 based voltage measurement

We were trying to investigate a simple way to make a representative LED output from a given input voltage. Basically this was intended to be a quick checker for the Battery we use in the Offline Inverters.

We found that LM3914 was a low part count Bar Graph display with Analog inputs available. And it was already in our dusty component drawer waiting for some one to use it.
This chip has a Direct Drive for the LED and contains a FLASH ADC kind of Structure for Analog Voltage to Bar Graph representation.
Internal Block Diagram (Sources: National Semi)
Pin Out Detail for the DIP Package (Source: National Semi)
We tried to use the Basic Circuit as per the Datasheet. But we did not have the exact resistances so we optimized them.
Basic Circuit for LM3914
We wanted to supply a Standard +5V and also wanted to adjust the threshold of the circuit so that we can measure different battery sizes and voltage levels.
So we modified the circuit by adding a 10k POT (BOURNS) in place of the R1 and R2.
Our Modified Design for Variable Voltage
Here the POT can be used to vary the voltage steps. In order to do this use another voltage source set at maximum of its value to be measured at J2 Signal input and then adjust the POT such that the Last LED10 is just lit. There you have the calibration done.
We also added a small filter 10K + 0.1uF to make sure we have clean input to the chip.
This is one handy circuit from our creations, hope that this would help you to develop your own application.

Friday, April 8, 2011

Opens Source Hardware Logo Selected

The Open Source Hardware Revolution about which we published some time back. Well now the logo for the hardware platforms that would follow this resolution has been finalized.
Source: Open Hardware
Another one without the Text - useful to generate the Eagle Overlay:
Source: Open Hardware

And from now all our Hardware would have the logo and the Liscense agreement to abide by it.

Tuesday, March 29, 2011

ExpEYES: Open Source Initiative to Physics learning through Experiments

We came across an astounding development made by our Bharteya(Indian) Students at Inter-University Accelerator Centre, New Delhi. This project is call the ExpEYES and is targeted to help students in universities and school to perform Science Experiments, Projects and Demonstration of concepts. The design is a combination of the Hardware & Software Framework combined to enable real time measurements and analyze data.
Source: http://expeyes.in/design-of-expeyes  
The best part of all this is its completely Open Source, including the Hardware. The software part is mostly made up in Python. And the entire development was performed in Linux. The hardware is interfaced via USB
and capable of operating as signal generator, frequency counter and low frequency oscilloscope. This also includes the internally generated references and +5V outputs to help interface the external peripherals.
Source: http://expeyes.in/  
There is well documented User Manual available for the Hardware as well as a set of 50 Experiments that can be performed on the ExpEYES.
The Software package need for this hardware is already available in Debian Package form as well as for other linux in a Tgz archive. Apart from the software packages included there are few generic Python libraries that might me needed to make this working, here is a list:
PyGrace - http://pygrace.sourceforge.net/
PySerial - http://pyserial.sourceforge.net/
The Graphing Front end used is Grace:

Picture of the Software Front end graphing the LCR Measurement
The Python Library needed to make the ExpEYES hardware interface is also available. The Firmware loaded on to the ATmega32 chip that the hardware uses as a core is available with Bootloader (as part of Another Project called MicroHOPE).

We congratulate the Innovators of the ExpEYES: Ajith Kumar, V V V Satyanarayana, Jimson Sacharias, Deepak Munda, S. Venkataramanan for their visionary creation. 

We are also thankful to PHOENIX Project
Inter-University Accelerator Centre, New Delhi for promoting Open Source in education and research in Bharat(India).