Skip to main content ↑ ↓

Messages

This section allows you to view all Messages made by this member. Note that you can only see Messages made in areas you currently have access to.

Messages - arupbsk

361
Project development, ideas, and suggestions / Re: Advanced alarm clock - Project idea
Oops. TI eStore didn't accepted my Mastercard debit card. They need a credit card number which I lack. Guess it's time for me to stop this idea, unless someone else of you agree to work with me in the software development part. I can design the hardware schematics though from my brain and eagle :) .
363
General discussion / Just a guide to reflow soldering, very easy method.
For soldering tiny SMD parts, many people follow many techniques like cute tip soldering iron, magnifier, microscope, sharp tweezers, or even ovens.
I follow another method for this purpose. I have a lamination machine, which is mainly used for TT, Masking, and other PCB fab needs.
I heat it at 200degree and open the upper cover to expose the heated element, which in my case is about 12"x2.5". My method works well for boards smaller than 2.5" width for the reason, but that's enough for many boards.
I then place the board(pre-soldered on pads) in the heating plate and press with tweezer to make it tight by my left hand and the whole board is heated within seconds. The heat is enough to melt solders on the pads.
Then just I take another tweezer and place paste type flux coated parts in right position. The flux melts the surface of the melted solder pads and components are placed in right tracks. If there is some mispositioned Ics, without any hesitation,I just use the tweezer in right hand to relocate it to correct location.
I After every parts get in position, it looks like the solders are scratchy and touching each other in some cases. Then I drop a few drops of liquid flux to the board and the soldered pads become neater by the surface tension of the solder, then it's time to switch off the heater and let the board cool for 5 minutes.
Finally it's time to clean the board with Isopropyl Alcohol and a brush to remove flux substances.

Items used: I use 73%Sn solder for this which is available at 28swg in my area, I use JYD soldering paste flux(china product) which leaves no black/brown goo in board after used. I use MAX GOLD liquid flux which is for SMD rework purposes. I use 6" long sharp steel tweezers(straight head) found in local shop.
Sorry environment lovers, I'm not eco-green soldering person because 100%Sn solder isn't available here, just 60% and 73% available.

Sample: The below FM radio module is dismantled and re soldered by my method, and looks exactly as it was new product.
[attachment=0]
364
Project development, ideas, and suggestions / Re: Advanced alarm clock - Project idea
[quote author="tayken"]
Actually MSP430 has its own user base that's kind of laying low. Ian did some projects with that, I am working on a project with a friend from local hackerspace. There is some usage + it is a good idea to have a large base for selecting components. Also Microchip introduced some low power PIC microcontrollers.
[/quote]
Yeah, I know Ian did a number of MSP430 in diylife. Will reply you with more information tomorrow.
365
Project development, ideas, and suggestions / Re: Advanced alarm clock - Project idea
About MSP430: I've seen TI showing budgetary price of 0.25$ for that, and also it's low power device, so that's a great idea. I have one doubt, that since it's not a popular chip among hobbyists, the user interest of making would be less (i think so). Hence I decided to use PIC or AVR, and this time chosen an AVR (Atmega 8L). There's enough space and just a few components so I've chosen the easiest(for diy) DIP version. I've chosen this for it's 8KB memory of which upto 2KB maybe needed for bootloader.
About data loss: A very serious point you noted out. I didn't think about it previously.

Anyways, a more complex design (still within the same size and with DIP ICs, as space is enough) would include a DS1307 RTC ran by another CR2016/32 for date/time, and a general 24C256 eeprom for reminders. There are lots of possibilities of adding many things, but seriously the simplicity would be lost.

For charging, a power out from the USB port maybe a good idea, so that battery will recharge while connected to USB. (But I doubt can CR2032 be recharged??)
For saving data, the internal 512Bytes EEPROM of Atmega8 can be used. (just a thought)
366
Instructables projects / Re: JDM2 PIC programmer build
[quote author="ian"]Hey Arup,

Two things. First:

1. Put a 9V1 Zener in place of 8V2 because of unavailability.

This could cause issues. The JDM programmer is at the very edge VPP (programming, 12-13volts) of usable voltage.

The other is the UBS->serial adapter. There are multiple issues: A) the timing is not correct, and JDM requires serial port timing, B) the voltage is not correct, most USB->serial adapters only give 10volts instead of the required +/-13 from a real serial port.[/quote]

Ok
1. I'll try to manage a 8V2 diode somewhere.
2. Will this be useful in leveling actual voltage of RS232 port? A RS232 to TTL to RS232 converter. [attachment=0]

And the third culprit maybe my laptop's OS. It's Windows 7. Maybe I need older version of windows like 98 or XP for better RS232 communication. What do you think?

I've measured voltage in the cable. It's 5.68V in idle mode, and comes 5.2x range while any operation is being done in IC-prog. So, isn't it good idea to just use a TTL-->RS232 converter in middle? (just thinking).
367
Instructables projects / Re: JDM2 PIC programmer build
Hi, I've just found that I was wrong and the programmer actually didn't programmed my PIC. It was not erased also.
I realized it when I tried to burn a new code, and saw old code still there in the PIC which ran the UPS.
But the code is looking like virus. Each time I read the code, it's different from previous codes, though actually PIC is working.
Did my alterations made this device useless?
I've selected 13V jumper as my PIC was 16F72.
368
Project development, ideas, and suggestions / Advanced alarm clock - Project idea
I think it would be much useful if we have a gadget like that with us. The hardware will contain a general purpose MPU with USB bootloader, and we just connect it to USB port for downloading our routines(*.csv files maybe) and appointments into it. There's reminder function in everyone's cellphones, but question is how much we use that? Sometimes we forgot important events, or get too busy in some work, and the time for another work is missed, or even a TV show.
With board size not more than the LCD size, it will be a compact gadget. The whole thing will run on a CR2032 battery and the time on device will be reset and synchronized every time user uploads new schedule to the device.
[attachment=1]
I thought will the device run in 3V by a CR2032? I've then assembled one LCD (3.3V version), one Mega8L MCU and one CR2032 in a breadboard and downloaded a testing hex file to check display, and it succeed. Text displayed in the LCD and it's more than 3 days now continuous displaying and battery is still enough charged. (To save battery, I've not connected the backlight)
[attachment=0]
Finally, the LCD would be software controlled and will be turned on only when alarm time comes and there is something to display or remind. A buzzer is added to the PCB for alarm purpose.
One switch maybe added with available IO pins to show time/date for say 5 seconds.

Any more recommendations for this idea? Please post below before I finally make one product.
371
Instructables projects / JDM2 PIC programmer build
I built the JDM2 based PIC Programmer which Ian shared in Instructables.
It was nice project with a good board layout that had wide tracks which gave very nice board when I did it with toner transfer method. [attachment=1][attachment=2]
Thanks Ian for that the board is with sockets for different types of PICs. The total cost involved in parts was some 75cents for me. I've etched a 10x10 copper laminated GE board for that  and then cut it to desired size, and if I consider the cost of the board and ferric chloride, printing, etc then the total cost including parts becomes just 1.5$.

The most important thing I liked is that it works with my USBtoSERIAL adapter, which was not supposed to support any JDM hardware, as I knew JDM hardware work only with real RS232 ports only.

I didn't had any virgin PIC to test the board, so I pulled up the 16F72 from my UPS, and tried to read the code, and rewrite the code. I succeed. MY UPS still works fine. 

Alterations I made:
1. Put a 9V1 Zener in place of 8V2 because of unavailability.
2. Put a 33mfd in place of 22mfd because of unavailability.
3  Built the 15K resistor by three 10K resistors, two in parallel and one in serial.
4. Used 25pF capacitors in place of 22..47..100pF because of unavailability.

The good: It worked with USB to serial adapter. I'm really happy for that
The bad: Too slow. 2048 bytes took 5 minutes to read, and 5 minutes to write. Hope that is not fault of the hardware, but of my USB to SERIAL adapter, or my alterations. I've used ICProg for this.
[attachment=0]
372
Project development, ideas, and suggestions / Re: Nokia LCD Breakout Board for uC interface by easy compon
Sorry for a mistake in part name. The 555 IC is used as astable multivibrator to generate 100khz pulses, but there in design I wrote NE555. But NE555 works in 5V and not in 3.3V. The actual part would be TLC555 which is a CMOS version and can run from 2V to 15V.
The NE555 IC is TTL version and if the user works only in 5V mode, then NE555 can be used without any problem.

( ! ) Fatal error: Uncaught exception 'Elk_Exception' with message 'Please try again. If you come back to this error screen, report the error to an administrator.' in /var/www/dangerousprototypes/forum/sources/database/Db-mysql.class.php on line 696
( ! ) Elk_Exception: Please try again. If you come back to this error screen, report the error to an administrator. in /var/www/dangerousprototypes/forum/sources/database/Db-mysql.class.php on line 696
Call Stack
#TimeMemoryFunctionLocation
10.01632448528session_write_close ( )...(null):0
20.01662580152ElkArte\sources\subs\SessionHandler\DatabaseHandler->write( )...(null):0
30.01662580928Database_MySQL->query( ).../DatabaseHandler.php:119
40.06002719688Database_MySQL->error( ).../Db-mysql.class.php:273