Signal Generator??? - Page 1
Forum section: electronics / general

author: JohnS_AZ
author_rank: Frequent Contributor
timestamp: September 24, 2010, 03:53:59 pm
content: I followed a link in another post (which I can't seem to find now) to this seller. Seems like they have some good prices on bare protoboards and some displays. But in poking around, I found what has to be theWorlds Most Stupid Signal Generator Kit...http://iteadstudio.com/store/index.php?main_page=product_info&cPath=17&products_id=186Dumb as it is, it's amazing they can sell the thing for $4.50 US.

author: djsb
author_rank: Super Contributor
timestamp: September 24, 2010, 04:14:55 pm
content: Can't even get the MCU part number correct. It's listed as 80C2951 but AT89C2051 on the larger image. Looks like a simple R2R DAC design judging by the number of resistors.

author: Zyvek
author_rank: Regular Contributor
timestamp: September 24, 2010, 04:17:48 pm
content: I think that company is a division of Dave's favorite Chinese brand.They seem to have a number of good prices on some familiar devices.

author: JohnS_AZ
author_rank: Frequent Contributor
timestamp: September 24, 2010, 04:26:58 pm
content: No where does it say what the frequency output actually is. And if you look at their scope photos all 4 waveforms are output at different frequencies! I guessing the big glitches are from using 10% resistors in the D/A.Man, crap like this makes me think "I really ought to get into the kit business!"

author: DavidDLC
author_rank: Frequent Contributor
timestamp: September 24, 2010, 05:32:57 pm
content: You get this unit and make a hack on the program to make it variable !Is a good price including the PCB !

author: Bored@Work
author_rank: Super Contributor
timestamp: September 24, 2010, 07:00:29 pm
content: $4.50 is IMHO ok for such a toy. Toy as in soldering exercise. But they should really mention that this is in no way a serious signal generator.If you want a variable on with better quality and source codehttp://www.myplace.nu/avr/minidds/index.htmIt is IMHO also not the most simple signal generator. E.g. the classic dual OpAmp square and triangle signal generator needs less parts, is equally crappy :-), and is adjustable with two pots.

author: JohnS_AZ
author_rank: Frequent Contributor
timestamp: September 24, 2010, 07:11:13 pm
content: Or you could build Dave's ...http://www.alternatezone.com/electronics/dds.htm(although the board art is probably no good ... seems the AD9835 is only available in TSSOP now)

author: Zero999
author_rank: Super Contributor
timestamp: September 24, 2010, 07:43:16 pm
content: The frequency isn't adjustableThe amplitude us fixedNo source code provided.What a load of crap!This gives me an idea: use an MCU with an RC oscillator for the clock and vary the capacitor and resistor to adjust the frequency. Oh maybe not.

author: slburris
author_rank: Frequent Contributor
timestamp: September 24, 2010, 07:43:59 pm
content: Change the frequency by changing the crystal? Who would buy somethinglike that? Oh wait.... isn't that how old CB radios used to work?If you only need square waves, a simpler circuit is a TTL can oscillator.$1 or less, 1 part :-)I'm not an analog guy, but even I wouldn't use a micro for this.For the same $5, how about this signal generator from Velleman.Offers 4 output types and the level is adjustable!http://www.mcmelectronics.com/product/80-7356&CAWELAID=445498319manual here:http://www.vellemanusa.com/downloads/0/minikits/manuals/manual_mk105.pdfScottScott