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1  Using Arduino / Microcontrollers / Re: Question about Arduino Leonardo: Average Lifespan? on: Today at 08:16:10 am
I like the economists' attitude - a successful economic forecast is when you get the sign (+/-) correct. smiley


I remember a cartoon many years ago:
- Lab all destroyed with smoking debris,
- Scientists in burned lab coats,
- Lead scientist at blackboard with a very long, complex equation,
    pointing to the decimal point in the results... and saying:
    "Gentlemen, this is a decimal point, when used appropriately..."

2  Using Arduino / Project Guidance / Re: ARDUINO MEGA on: Today at 08:10:38 am

Dude the hyperlinks in the Build lists on that link has all the sources...  both U.S. and China...
Repeated here for completeness:
OR (different pinout, same controller)

Pro Mini


3  Using Arduino / Microcontrollers / Re: Third PWM channel on ATTINY85 on: Today at 08:05:25 am
Wow.  You are seriously full of...

OMG!  I really must stop drinking coffee and reading these posts  smiley-grin  Another coffee spew ... coffee does seem to clean the keyboard fairly well / Hopefully the moisture seal in the keyboard is working !  No matter though, I can buy another PC, but this humor is priceless!

4  Using Arduino / Storage / Re: Retrieve value from spesific cell in excel..?? on: Today at 08:01:40 am
That's fine but I think it's time review the original post which would imply that, not only would you need to know VBA, but also you need to teach Arduino VBA, so it can do the looking. And likely all for no purpose - or no purpose that can't be done with a CSV. I've heard it said that 99% of all the real work ever done in Excel can be done with a CSV file. I'm inclined to believe it. 

I reread the original post.  I believe the Op wants the Excel up and running continuously and the "Value" shown in the cell to be redisplayed onto a LCD screen.  I cannot determine from the post if the Arduino really needs to know the value for any use other than sending to the LCD.  So, the procedure would be for VBA to send to Arduino... over serial through the USB port is likely the most viable, although two-way can be established over USB with the right descriptors... perhaps to a Leonardo.

If we could coax Excel into producing a single ASCII file for the Arduino, we would still need to manage the opening of the file and the access to the file data contents.  This just seems silly.

Reading a file stream and extracting info is really very, very easy.  The character stream coming from reading an SD card is no different, in theory, than the stream coming from a keyboard.  I have posted last year a simple example of how to parse and manipulate such a stream (Somewhere in the Project Gallery) but also here:

Presumably, the Op's Spreadsheet has a lookup table for UPC being read by the barcode reader.  Such tables are likely not appropriate for an Arduino even if we put in additional EEPROM.  Then there is probably a price table and tax calculations (assuming a commercial terminal... but it is really not relevant what is being stored and looked-up.)  I think the Arduino is just managing the LCD, but the Op probably should confirm that belief.

5  Using Arduino / Storage / Re: Retrieve value from spesific cell in excel..?? on: April 22, 2014, 09:06:18 pm

Nothing wrong with that.  VBA beyond simple macros is a skill centric only to Microsoft Office fanboys (and fangirls.)  But, when one is working with Office, VBA is pure magic.

6  Using Arduino / Storage / Re: SD logger - with several sensors - not fast enough on: April 22, 2014, 09:00:03 pm
I think that few newbies know your forum reputation...  I know you are generally modest but you could probably quelch a lots of dialog by introducing yourself as the author of SD library  smiley-lol

Assuming you are not just toying with your prey.  Yo tha man, dude.

7  Using Arduino / Storage / Re: Retrieve value from spesific cell in excel..?? on: April 22, 2014, 08:21:50 pm
how I want to read the value from the specific cell in excel?
I was plan to scan the barcode and send the bar ID into specific excel cell inside the SD card. For example...the ID show in cell F5.  Then at cell F6 will show the S/N for that ID (using excel formula). I want the arduino to read the S/N inside cell (F6) and print out at LCD..
*i ve the list all barcode ID in comlumn A and S/N at column B
I ve try to search every where in internet and still not found the solution my problem.

Yes, this can be done in realtime which is what I believe you want.  Excel is a rather complex program but the solution lies in VBA, the programming language of Excel.  F6 is a formula that has a visual representation that is shown on the monitor via a buffer.  So, VBA can be used to map F6 to another cell that can be used to actually have the digits.  This can then be exported as a range to a disk file OR can be sent oner serial to the Arduino or even directly to a serial display.
The concepts are advanced and the implementation is Expert.

8  Using Arduino / Microcontrollers / Re: Third PWM channel on ATTINY85 on: April 22, 2014, 07:50:49 pm
The Digispark tiny85 uses the Bluebie boot loader and is designed to be programmed without the need of reset.  Therefore, you can get 3 PWM and reprogram too.


Build your own:
9  Using Arduino / Project Guidance / Re: ARDUINO MEGA on: April 22, 2014, 07:24:43 pm
but my problem is TIMING.

The forum gets this question every so often... For example:

Essentially, while the Arduino has a reasonably accurate resonator, it is not as accurate as a precision quartz/watch crystal.  For under $20, you can add a very accurate time base:

For constant year in, year out accuracy there are solutions that include GPS or Internet Time Servers.
My clock:

10  Using Arduino / Microcontrollers / Re: Alternative to 16U2 on: April 22, 2014, 07:32:26 am
admittedly nice being able to plug in a new chip on those big socketed boards but pro-mini is so cheap at $2-$3 shipped dollars its almost not worth it.

It's a good point but the sub-$3 range is for the China variety of the clone.  These clones often have varying pinouts, especially around the Vcc/Gnd area of the board.  So caution needs to be utilized and the realization that one board ordered today may differ from one board ordered two months ago.

The other issue, which should be considered, is the need to have a soldering iron and decent skills in using said iron.  Even if you just need to solder the headers for breadboard use.  Soldering and unsoldering wires to the little boards will eventually cause copper foil lift at which time the board.

It is a cheap and viable solution, but not one that I would recommend for the "My First Arduino" award.  Buying a UNO has many benefits for newbies.  For EE's, HAM's, or ET's with hardware buildout experience... yea, go for the cheap... they generally work.  My last shipment of 5 Pro Micros and 2 dead units... one was revived with reflashing the bootloader for the 32U4 but one is eternally dead.  The previous 10 Pro Micros were 100%.  2 duds out of 15 may be an unacceptable rate of failure and most newbies will be unable to flash the 32U4: something to think about.

11  Using Arduino / Microcontrollers / Re: Question about Arduino Leonardo: Average Lifespan? on: April 22, 2014, 07:19:15 am
Two orders of magnitude would mean an error of 100 times the correct value - i.e. 10,000  (or 1) where 100 is correct.

I should have paid more attention in math class!  My bad  smiley-sad

12  Using Arduino / Displays / Re: TFT touch LCD YX32B/34B on: April 21, 2014, 07:36:48 am
Too small, no touchscreen.. but a nice try...

Any1 else ?

There are SPI TFT RGB screens that are larger than 2.2 inches!  My reference was to the ease of using SPI, not to he screen size.  Generally, a simple search of the forum will answer most common questions...

Adafruit also has a nice TFT RGB that has an "add on" touchscreen.  Her stuff always works, is well documented, is supported, and you pay the extra for that service.  But if you need something that can be integrated quickly, has a 100% guarantee of working as marketed (integration with other things is not guaranteed... you may have to work to make it happen) ... well, the price may be reasonable.

Sparkfun also has a good selection and good support from my experiences.

13  Community / Exhibition / Gallery / Re: ILI9340 SPI 2.2 inch color ASCII serial terminal on ProMicro 32U4 on: April 21, 2014, 07:27:35 am
I haven't received them yet.
It was on
I saw they were at 2.2 GBP at the moment.

Wow.  Maybe a short report when they arrive, seems like a great price if that included the shipping.  Also, would be interesting to know if J2 connector is standard Chinese variety or if it is the Adafruit pinout.  Trying to keep track of the different pinouts for LCD's is a major pain.  I have started to just build a "notes.h" section into every program sketch where I use ASCII to draw out the pinouts used in the sketch.  The entire tab is a bit comment, /* ... */, and is a very useful way to evolve notes as sketches get modified from a basic 328P-PU to a Mini to a Micro to a 2560, etc.


14  Using Arduino / Microcontrollers / Re: Alternative to 16U2 on: April 21, 2014, 07:22:20 am
I use a Sparkfun FTDI BASIC for my 3.3V Pro-Mini, 5V Pro-Mini and breadboarded ATmega328 chips. It works great. no problems.
Nice.  Have one... rarely used, however, but always works.

i am always amazed at the number of people who still like to put that usb/tll converter on every board. talk about redundancy.
Yes!  And so cheap in today's marketplace... if one takes a few minutes to look for a bargain.

Lots of options.   I just did not want a newbie to run out and buy a surface mount 16U2 or 32U4 and a 328P-PU just to copy a UNO design in detail.  Deviating down the forerunners to UNO before the 16U2 is a better approach, IMO.

15  Using Arduino / Project Guidance / Re: UNIVERSITY PROJECT: LED, Speaker, Motor, Battery on: April 21, 2014, 07:17:55 am
... I was looking at LilyPad Vibe Board ( do I need any specific components to connect this with, an arduino UNO for example? What sort of things is the UNO for - ie what would be the best board for all the above components?

I think you are falling a common trap, trying to anticipate the future without the benefit of a crystal ball.  The UNO is a basic workhorse, with a replaceable chip just in case!  Blank chips are a small fraction of the UNO cost.  But as you move up the product line, you typically get more SRAM and more I/O capability.  Your "middle of the road" Arduino is probably the Mega2560, with lots of I/O and 8K of SRAM.  It does not have a replaceable microcontroller... if you fry it, you might as well bury it.

I would strongly recommend the UNO in any event... it is a good prototyping platform for most small/medium projects.  It is a workhorse.  It is easily home built into a simple protoboard so that the UNO is not bound to a project.  It is the physical BIG brother of those little Mini clones from China for $3.  The UNO will accept a daughter card (called a shield) and many shields are available.

When you are working with an UNO, you have a standard frame of reference.  You have a common way of communication for a problem to the forum.  There are zillions of UNO's out here and the chance of finding something weird that has not been seen before is small.

As your project evolves, you can think about whether you need to buy a project Arduino.  Maybe the UNO will suffice, maybe not, but they are relatively inexpensive as compared to college tuition or even a round of beers at the pub.

As you work through your project ideas, begin a spreadsheet.  Identify the component, sensor, output device on the spreadsheet along with the power requirements and the protocol used... serial, SPI, I2C, direct port, buffered port, etc.  Also list any required libraries that are common... LCD, SoftwareSerial, etc.  By keeping track of physical requirements and the software needed, it is easier to identify the proper (final) board.

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