Open Source 3 Channel Frequency Generator

[Yucca]

Thanks europeanhillbilly (Nice handle by the way!)

Fire away with any questions as and when you want.

If you want to just build the low freq version to get started then just buy yourself a LCD shield, quite cheap and fast ship to europe and its pin compatible with the Duemilanove:

http://www.nuelectronics.com/estore/index.php?main_page=product_info&cPath=1&products_id=2

with just that and your arduino board you will get 5V 20mA PWM generator with adjustable freq and duty cycle by loading up the program listed on page one of this thread.

The only hardware work you will need to do is to clip or solder a single lead to one of the port pins and then use that output wire to drive FETs on breadboards etc.

Yucca.

[europeanhillbilly]

Great, I'm about to order the LCD keypad shield and a ProtoShield Kit. Thanks!

One killer feature would be to have a shunt connected to the Arduino that measures the amp draw. The Arduino could then figure out the duty cycle to keep the load at that power level.
Any suggestions?

What you call LF (is 1Mhz really so low? ) should be enough for the first tests. This may be a stupid question, but the arduino page says the hardware has multiple pins configurable as PWM output. I guess then those pins can only be driven by *one* frequency at a time, is that right?

I'm really looking forward to this, hope you don't mind me being a total newbie with microcontrollers. :/

Greets, ehb

[Yucca]

Great, I'm about to order the LCD keypad shield and a ProtoShield Kit. Thanks!

One killer feature would be to have a shunt connected to the Arduino that measures the amp draw. The Arduino could then figure out the duty cycle to keep the load at that power level.
Any suggestions?

What you call LF (is 1Mhz really so low? ) should be enough for the first tests. This may be a stupid question, but the arduino page says the hardware has multiple pins configurable as PWM output. I guess then those pins can only be driven by *one* frequency at a time, is that right?

I'm really looking forward to this, hope you don't mind me being a total newbie with microcontrollers. :/

Greets, ehb

Yes the arduino has a few PWM pins and you can generate I think 3 different freqs, I´m just using one PWM output. Unfortunately the LCD and jogwheel take up the others.

1MHz is fairly quick, but it´s LF. I want HIGHER! I would like to goto GHz in the end, but this I don´t know enough about when it comes to stable(ish) oscillators and amps,.

I will be adding a software gate function to the LF channel this will vork in the ELF to VLF band range. And then you will be able to generate Meyer like waveforms.

I am thinking about current sensing at the moment, a shunt would certainly be a good way of measuring RMS amps via one of the ADC pins. Will have to smooth output with a parallel RC circuit prrior to sampling because the sample rate is quite slow.

Microcontrollers are easy with the Arduino, Just need to know a little C or C++. The free dev environment is really simple to setup, just plug the board into USB and go!

What are you going to use it for first, HHO?

Yucca.

[europeanhillbilly]

I was just re-reading your posts and the code here
HHO will most likely be my first use, yes.
Although I would also like to test PWM with a plasma electrolysis cell. Not sure what parts I'd need for switching 300VDC though.

I need to crawl before I walk, so my first use would be dimming an LED

I got the Duemilanove in my hands right now, sweet small piece of hardware. I haven't coded in C yet, only 'stupid people' stuff like ruby, php and some ecma script. Will need to wrap my head around it, but should be managable. Haven't done alot with electronics yet either, so yeah, I'm a bloody beginner.

I'd be really thankful if you'd manage to find a way for measuring the amps. Have you heard of the "HHO VMU"?
http://www.xo1ox.net/hho/shop/item.asp?itemid=33
Seems to be a good product, but open source is always a better way Reading up on some arduino libraries, OBD monitoring could well be on the feature wishlist for 2010 or so

I haven't ordered an LCD shield yet, will do right now. Do arduinos tend to be easily breakable? Then I'd order a second one, just in case.. (now that I need to order in GB anyways)

Cheers and thanks for your efforts, ehb

[Yucca]

Yes I´ve seen the VMU, it is indeed a sweet little unit.

I also have another project on my bench at the moment called HHOBox.

http://www.hhobox.com

It´s still in devmode but preliminary specs are:

DC...1MHz
PWM
Gating
1 channel RMS Amps
FET Heatsink Temp
CELL Temp
EFFIE up to four sensors
Audio alerts

Yucca.