RE: [funwithtransistors] FW: R-2R DAC


Dec 5 8:06 PM

 


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#2309 Dec 5 8:06 PM

�� ��Regards. ��Max K 4 O D S. ��I've Never Lost the Wonder. ��Antique Electronics Site: www.angelfire.com/electronic/funwithtubes/ ��

��From: funwithtransistors-owner@yahoogroups.com [mailto:funwithtransistors-owner@yahoogroups.com] On Behalf Of Daniel Koller kaboomdk@... [funwithtransistors]Sent: Tuesday, December 05, 2017 9:20 AMTo: Andrew Jardine andybiker@...>; Funwithtransistors Moderator funwithtransistors-owner@yahoogroups.com>Subject: Re: R-2R DAC



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#2310 Dec 5 9:18 PM

I hate today but the design is way to complex.. There is no need to build anything like this.. The entire thing can be done with a $3 single board uP.. It has the computer. the memory and the DAC and more and self for under $3 free shipping. . This is overkill for a for bell but it allows room for growth.www.ebay.com/itm/STM32F103C8T6-ARM-STM32

On Tue, Dec 5, 2017 at 12:06 PM, 'MAX' max@... [funwithtransistors] funwithtransistors@yahoogroups.com> wrote:

...Regards..Max K 4 O D S..I've Never Lost the Wonder..Antique Electronics Site: www.angelfire.com/ electronic/funwithtubes/.

.From: funwithtransistors-owner@ yahoogroups.com [mailto:funwithtransistors- owner@yahoogroups.com] On Behalf Of Daniel Koller kaboomdk@... [funwithtransistors]Sent: Tuesday, December 05, 2017 9:20 AMTo: Andrew Jardine andybiker@...>; Funwithtransistors Moderator funwithtransistors-owner@ yahoogroups.com>Subject: Re: R-2R DAC



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#2311 Dec 5 9:29 PM

Sorry hit return a little to soon.

These little boards are all .over eBay. . There is no way to buy the parts for they selling price. . The .There are enough pins so you could have several doors each with it's own sound, It would be easy to load new sounds from USB connector to computer.. The DAC is built in but yo'd need a power amplifier. . .

Using a olde prob and address line dan home made DAC is something from the 1970's.. Today we'd use a one chip design for about $1.

In fact almost every time you think of building some small digital device r controller that $2 STM32F board seems like the best way.. May as well spend $20 and buy 10 of them.

They are easy to program.. You can use the Arduino IDE or "MBED" IDE. . Of course other methods .too but then you are needing to be a specialist.. Arduino .or MBE are suitable for hobbyists doing a one-off project.

On Tue, Dec 5, 2017 at 1:18 PM, Chris Albertson albertson.chris@...> wrote:I hate today but the design is way to complex.. There is no need to build anything like this.. The entire thing can be done with a $3 single board uP.. It has the computer. the memory and the DAC and more and self for under $3 free shipping. . This is overkill for a for bell but it allows room for growth.www.ebay.com/itm/ STM32F103C8T6-ARM-STM32

On Tue, Dec 5, 2017 at 12:06 PM, 'MAX' max@... [funwithtransistors] funwithtransistors@ yahoogroups.com> wrote:

...Regards..Max K 4 O D S..I've Never Lost the Wonder..Antique Electronics Site: www.angelfire.com/elect ronic/funwithtubes/.

.From: funwithtransistors-owner@yahoo groups.com [mailto:funwithtransistors-own er@yahoogroups.com] On Behalf Of Daniel Koller kaboomdk@... [funwithtransistors]Sent: Tuesday, December 05, 2017 9:20 AMTo: Andrew Jardine andybiker@...>; Funwithtransistors Moderator funwithtransistors-owner@yaho ogroups.com>Subject: Re: R-2R DAC



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#2312 Dec 6 2:45 PM

Thanks Chris,

�� ��But....1) I am a Luddite.�� 1970's is just fine by me!2) I have all the parts in boxes, including DACs3) Don't underestimate the programming time, and time to set up the IDEs to program the uP's, though that's something I want to get into.4) This is after all "funwithtransistors".�� ��Transistors are "so 1960's"!�� ��

...so being stubborn and sticking to my design.�� Andrew Jardine has built essentially the same circuit, but my reply to him did not go back to the group as intended.�� I am further inspired to build it using an EPROM (I've really got a lot of these).

�� But the thing I am spending the most time on is not so much how to generate the sound, but how to trigger it.�� I'm trying to make it sort of universal, and most importantly NO MAINTENANCE.�� The last thing I need is to have to fix a doorbell.�� There are no nuances to a doorbell.�� You press the button and it has to work.�� So my circuit has to be simple, reliable and robust.�� ��That also means to me no batteries.�� So I need to power it from the bell circuit and still be able to use the button.�� In all likelihood, the wire goes from the transformer, to the button on the door, to the bell.�� I thus only have power when the button is pushed, so I need to figure out how to work around that.�� �� ��

�� Best I have figured for now is to put a diode across the doorbell button.�� ��Then I will get half-cycle DC to keep the circuit live.�� When the button is pressed, I'll get AC at the circuit board.�� I can then rectify that to get a negative voltage which I can use to trigger the circuit.�� ��Yes, I could monitor an input pin of an Arduino.�� ��But once I add all the supporting circuitry to the board, and the amplifier, then I might as well just roll my own.�� It will cost the same ($13 for 5 boards!).�� ��The only difference is the added design time, but that's the part I enjoy most these days.�� It's a puzzle to lay it all out.����

�� ��All that said, I am not totally backwards.�� I have programmed pic chips (but again, prefer to do it in machine code rather than high level language, at least for now).

�� ��Dan







On Tuesday, December 5, 2017, 4:30:07 PM EST, Chris Albertson albertson.chris@... [funwithtransistors] funwithtransistors@yahoogroups.com> wrote:







��Sorry hit return a little to soon.

These little boards are all ��over eBay. �� There is no way to buy the parts for they selling price. �� The ��There are enough pins so you could have several doors each with it's own sound, It would be easy to load new sounds from USB connector to computer.�� The DAC is built in but yo'd need a power amplifier. �� ��

Using a olde prob and address line dan home made DAC is something from the 1970's.�� Today we'd use a one chip design for about $1.

In fact almost every time you think of building some small digital device r controller that $2 STM32F board seems like the best way.�� May as well spend $20 and buy 10 of them.

They are easy to program.�� You can use the Arduino IDE or "MBED" IDE. �� Of course other methods ��too but then you are needing to be a specialist.�� Arduino ��or MBE are suitable for hobbyists doing a one-off project.

On Tue, Dec 5, 2017 at 1:18 PM, Chris Albertson albertson.chris@...> wrote:I hate today but the design is way to complex.�� There is no need to build anything like this.�� The entire thing can be done with a $3 single board uP.�� It has the computer. the memory and the DAC and more and self for under $3 free shipping. �� This is overkill for a for bell but it allows room for growth.www.ebay.com/itm/ STM32F103C8T6-ARM-STM32

On Tue, Dec 5, 2017 at 12:06 PM, 'MAX' max@... [funwithtransistors] funwithtransistors@ yahoogroups.com> wrote:

������Regards.��Max K 4 O D S.��I've Never Lost the Wonder.��Antique Electronics Site: www.angelfire.com/elect ronic/funwithtubes/��

��From: funwithtransistors-owner@yahoo groups.com [mailto:funwithtransistors-own er@yahoogroups.com] On Behalf Of Daniel Koller kaboomdk@... [funwithtransistors]Sent: Tuesday, December 05, 2017 9:20 AMTo: Andrew Jardine andybiker@...>; Funwithtransistors Moderator funwithtransistors-owner@yaho ogroups.com>Subject: Re: R-2R DAC







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#2313 Dec 6 10:14 PM

A software version of this would be nearly trivial.. One pin goes low you copy the music data out one of the analog pins.. Likely about a dozen lines of code in total. And the PCB is already made. ..

But if the goal is to be limited to only parts that were available before 1980 with no microprocessors involved.. Now you have a good sized logic design project. . I studied computer engineering at UCLA in the late 70's and I do remember 74x00 logic gates and the Z80 microprocessor. . .Memory was expensive and true audio grade DACS were not cheaply available.. Doing this "right" back then would have taken .weeks. . We had to laterally "tape" PCB designs and shoot litho film and then expose and develop and etch PCBs, use wave solder baths and so on. . It was really slow and expensive.. Designed had high parts counts and mistakes were easy to make

I prefer building 1940's vintage tube gear to 70's vintage logic.. It is physically less work. . .In fact I only used 70's vintage logic in school.. By the early 80's it was all done in software. . Big PCBs filled with small scale chips was a short period of time. .

Back to powering it: . Yes a diode across the button would supply continuous DC and you could filter that the and like have enough volts across a filter cap to run one of those 7805 regulators. .

Then when the botton is pressed you could us another diode to rectify a negative DC voltage that could close a mechanical relay that pulls a log line to zero and latches a flip flop. . The end of the sound recording resets the flipflop, Wail set a counter runs at (say) 24K and clocks the recording out of the ROM to a DAC. .

You need a FF to use as a latch because the person pressing the button might not hold it long enough to play the entire song recording or he might press multiple times and you want to act on only the first press.



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#2314 Dec 7 1:10 PM

Hi Chris, Daniel, ��I would like to try an STM32F103C8T6-ARM-STM32 board as I do have some experience with the Arduino boards.I.ll read up on this micro, it looks good.It would need to have an amplifier, power switching and a microSD interface added.I.m not sure that I could get it much smaller than the original though.The hardware development time is much shorter but software may take some time (for me!)I too have a soft-spot for tube-gear and do have several valve radios as well as many home-made nixie clocks (these are a nice marriage of micros and high voltage!) ��I attach a picture of my original board as well as the schematic of the power switching (as I remember it)I think that originally it took me a week of spare time to go from concept through prototype to finished PCBWhat do you think?Cheers,Andrew

��From: funwithtransistors@yahoogroups.com [mailto:funwithtransistors@yahoogroups.com] Sent: 06 December 2017 22:14To: funwithtransistors@yahoogroups.comSubject: Re: [funwithtransistors] FW: R-2R DAC



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