Rich man EFIE

[TheOne]

Hi, they are something missing in my circuit that I need to buy to finish it, the DAC (digital analog converter), at first I was sure the PIC have one but that was only the ADC, anyway the coding is done, everything is ok, just need to add the ADC and time .

Making a circuit to sell it is a good idea but this kind of circuit need professional soldering and board, I am not sure how a clean circuit will cost and i probably need to buy/order a big quantity to have some, that mean I need to sell a lot of circuit to cover all the cost.

Maybe I can get some idea/help from other to make this append.

[Yucca]

VERY nice indeed!

Great work on using 4bit address mode for the LCD, it sure saves microcontroller pins

You can do DAC with minimal external circuitry: Use fast PWM by utilising a timer pin and interrupts, then smooth the pin output using just a small ceramic capacitor with its charge slowly leaking to ground through a resistor.

I am working on a signal generator coded in C++ on the Arduino platform with external programmable oscillators, I have pretty much finished the GUI, it uses a jog wheel and a 16x2 LCD like yours, I will start a thread soon with photographs and source code.

I notice you appear to have user defined graphics on your LCD. I presume it has a standard Hitachi controller on it, if so could you give me a heads up on doing UDG?

All the best, Fraser.

[Yucca]

Also, forgot to mention:

If you want to sell ready made units then you could use Arduino or Freeduino boards, the great thing is that they come ready built with power regs and USB interfaces on and theyÂÃ,´re pretty cheap.

The even greater thing is that you can buy off the shelf plug on boards for them called "shields", you can get LCD shields with joypads on them. You can also get bare shields like veroboards for building your own projects on. So your unit could be one micro board, one bare shield with your input and output signal conditioning on, and one LCD shield, you could just bag these up and sell ready programmed as a kit.

The other nice thing is that the development environment is C++ or C and itÂÃ,´s very good quality and FREE to download!

I recommend Freeduino because itÂÃ,´s an open source board, and itÂÃ,´s fully compatible with industry standard Arduino, and itÂÃ,´s cheaper

http://www.nuelectronics.com/estore/index.php?main_page=index&cPath=1

Of course the only downside would be that youÂÃ,´d have to port your code over  but nonetheless it maybe something to think about.

Fraser.

[TheOne]

Yes indeed for the LCD. Its quite easy actually to make your custom graphics but its basically you are creating new character font.

Here the link of the PDF (http://www.serialwombat.com/parts/hd44780.pdf), all infos needed to generate your custom graph character. For the progress bar I am using a couple of character with 1/2/3 etc.. columns and when its time to show the graph I call a beautiful little function that render the right character on the screen

I was aware of the method you are talking about (PWM) but I think to get a very accurate voltage between 0v and 1v a DAC is the way to go?

Nice platform, but my question is was is a Arduino? a chip like dsPIC ? dsPIC are very fast, many pin (64), ADC, enough memory, also how cost a dev kit for this platform?

Sylvain

[Yucca]

Yes indeed for the LCD. Its quite easy actually to make your custom graphics but its basically you are creating new character font.

Here the link of the PDF (http://www.serialwombat.com/parts/hd44780.pdf), all infos needed to generate your custom graph character. For the progress bar I am using a couple of character with 1/2/3 etc.. columns and when its time to show the graph I call a beautiful little function that render the right character on the screen

I was aware of the method you are talking about (PWM) but I think to get a very accurate voltage between 0v and 1v a DAC is the way to go?

Nice platform, but my question is was is a Arduino? a chip like dsPIC ? dsPIC are very fast, many pin (64), ADC, enough memory, also how cost a dev kit for this platform?

Sylvain

Thanks for the LCD info

On Arduino the processor is ATMEGA168 16MHz 32kbyte program, EEPROM, 8 bit RISC, 16 io pins, 8 ADC, SPI and more. ItÂÃ,´s more than powerful enough for your project I think.

You can get VERY accurate voltages using fast PWM and conditioning circuit. 0 to 1 V with 0.01V resolution should be no problem provided youÂÃ,´re driving high impedance load like opamp. A cheap DAC chip wonÂÃ,´t be that much more accurate and in fact alot of DAC chips use PWM in their internal architecture. But for maximum accuracy an expensive DAC chip canÂÃ,´t be beaten.

The development environment for Arduino or Freeduino is free:
http://www.arduino.cc/en/Main/Software

Fraser.