A Simple Signal Generator

[Jon Chandler]

A square wave generator can be a handy tool on the bench.  I recently needed one to simulate the signal from a Taos TSL-230R sensor so I built a simple adjustable duty-cycle square wave generator using a PIC 18F series.  When I had to resurrect it to test some piezo beepers, I put it in an enclosure and made a Windows app to control frequency and duty cycle.





The built details, firmware source code and a hex file and the Windows application can be found here:

http://www.clever4hire.com/throwawaypic/tap-28-applications/simple-signal-generator---1

Jon

[Simon]

"who you gonna call - Spam busters"

cmon, all your trying to do is sell the board, you first post and it's to advertise something

[armandas]

If we were to call "Spam Busters" you'd be the first one to go..

[JohnS_AZ]

It's a cool little open project that you could build from his plans without buying the board. Further he linked to the plans and not to the 'buy this board' page so I wouldn't call it spam.

And it is kind of a cool little board.

[Jon Chandler]

It's true, I'd be happy to sell you the board, at a pretty reasonable price.  The markup over cost about covers a trip to the post office.  But if you read the site and ask nicely, you'll see that I'll send you the Gerber files for free.  I'm waiting to make a run of revised boards to verify my re-design before I post the Gerbers on the site.

But the circuit is almost trivial to build.  The schematic is there and what, there are maybe half a dozen components?  Really not too difficult to build using a perf board, a bread board, most any dev board or a board you fabricate yourself.  The TAP-28 board is a board I designed for my own use, and I've made available to the community.  It's an alternative to the rat's nest of wires on a bread board that some people show as a "project" that will work until somebody walks by and a jumper falls out.  Or spending $30 for an Arduino board.

My site also has links to several free compilers that work well.  I wrote the firmware in Swordfish Basic.  Because of the inefficiency of the string handling routines, I don't believe this signal generator firmware can be compiled in the free version.  The previous version (which is linked from the article) will happily compile under the free version.  Or, if you use the same PIC, crystal and connections, the compiled code is just a click away.

I find the signal generator handy to have on my bench.  Just trying to share with the community and perhaps offer a board that makes small projects accessible to people who don't have access to cheap boards.  Sorry if I have offended.

Jon

[Simon]

yea i know i was being harsh, we've had a few silly posts lately.

[Jon Chandler]

Matter of fact Simon, it looks like this is exactly what you need for testing your "DC to AC converter"   It's a simple way to generate the 50 Hz signal you want.

[Simon]

well it could work as the control part as it's a PIC (and that's the only qualifying bit of it) but then I need two alternating signals and a set dead time so really i'd be writing the software I'd write anyway for my regular 12F615 pic, but then I can breadboard it as fast or put it on a PCB that is 30 X 40 mm just the size I was given as the limit for that project, it does not include the power driving circuitry so I'd need to make a board with that on it anyway.

It's a good idea for people that don't want to do a lot of PCB making and want to play with code but as a final project it wastes a bit of space (or a lot for simple stuff) which is not always an option, I guess it's something between one of those full blown pic labs and a general use board but if you need to make daughter boards why not make the whole board ? It's obviously a concept that worked for the designer but might not be everyone's cup of tea.