New projects on www.sm0vpo.com

Hi Harry,
it makes sense in such case. A USB/parralel dongle opens the project to all who use contemporary PCs without modification. I personally dislike fiddling with the guts of notebooks.

VBR from Ivan

Ivan wrote:Hi Harry,
"... all I need is to connect the EPROM to the computer parallel port ..."
But PCs with the genuine parallel port are absolutely rare now. USB has replaced LPT: Do you intend to use an interface of some sort?

VBR from Ivan

Hi Ivan,
I only have one computer that does NOT have a parallel port and a serial port. 4 laptops and one DELL desktop.
The only computer that does not have a parallel port is this new ASUS laptop, but I have a USB to Parallel dongle for that.
I still use firewire because it is faster than USB.
All the other computers are home refurbished.

Yes, I will have a 4040 counter (to address the EPROM). Also a diode 4-bit + 4-bit switch to select the Hi or Lo nibbles from the EPROM data out when reading the EPROM.

This time there will be no buffers between the PC and the EPROM, so the circuit is dead simple

I will also use the same interface card to program PIC chips, but with a little modification. I am really looking forward to getting this working. The old version of the card looked a bit makeshift.

Best regards from Harry - SM0VPO

zsolt wrote:Some question about the original GDO , the first one . 
It has a modulation input . 
Is that more amplitude then frequency mod . ? 
Can i take the modulated signal from the drain to make use of that ?

The original had both AM and NBFM, simultaneously. It was just a crude method of getting a signal into a repeater receiver - set the GDO @ 10.7MHz. I alsi had a 1K tone in the one in Saudi. That always gave me -4.5dBmo so I could calibrate the network, and didn't need a signal generator in the van.

The other tone oscillator in the GDO was 71.9Hz to open the tone-squelch.

BR Harry - SM0VPO

zsolt wrote:hello to all, 
about the doorbell , i think that this litle module could be useful  https://www.joom.com/en/products/5d919f398b2c3701015b9ae1

Hi Joy,
That is a really interesting module. I shall have to look closer at that.

Thanks for the link - Harry - SM0VPO

Hi Harry,
"... all I need is to connect the EPROM to the computer parallel port ..."
But PCs with the genuine parallel port are absolutely rare now. USB has replaced LPT: Do you intend to use an interface of some sort?

"The only thing I have against the single-card computers is that a RaPi, for example, takes some time to start ..."
Yes, MCUs which use a full operating system with a filesystem (e.g. Linux) like RasPi and Onion must boot at each startup. PicAxe and Arduino incl. clones start in tens of milliseconds.

VBR from Ivan

hello to all, 
about the doorbell , i think that this litle module could be useful  https://www.joom.com/en/products/5d919f398b2c3701015b9ae1


//_____________________________________________
Some question about the original GDO , the first one . 
It has a modulation input . 
Is that more amplitude then frequency mod . ? 
Can i take the modulated signal from the drain to make use of that ?

Hello Ivan,
You are 100% correct. The easiest way would be to use the Arduino nano (I have loads of them), exactly as you suggest.

But, Ericsson used to use D2732D EPROMS in all their GSM radio base stations for the firmware. Then they moved GSM production to China, the factory in Kista had 1000's of unused EPROMS that they were going to put in the bin. So I cadged a whole heap of them. I have a few 100 of them. With a little bit of homebrew I can use them.

I also used them to make my own PLA's, and for both projects I need an EPROM programmer. I already have all the HW I need, all I need is to connect the EPROM to the computer parallel port, with a 5V and a 25V power unit, and I am in business. I do enjoy playing about with them.

My EPROM burner I created a few years ago is lost in all the house moves, so I want to make a new burner card. It is more for the fun of it than to find an easy way. A bit like making a baby; it is not a profitable investment and takes time to complete (but people still want them ) (it is not the destination, it is the journey )

The only thing I have against the single-card computers is that a RaPi, for example, takes some time to start, but a CD4040 and an EPROM start fast enough to have no power at all, until someone pushes the button. Then it can play a tune, and FF in the memory cuts off the power so it is ready for the next Beethoven's 5th event. This means I do not need a PSU or a place to plug it in. A battery will last for years.

Many, many, many years ago I did something similar with a cassette player:
Doorbell button latched a relay, VOX detected the music, cut off the latch but kept the power relay on. Music stopped and relay dropped out, cutting off the power. The boring part was recording the bit of music 250 times on one cassette tape. It lasted months on one battery and without needing to rewind the tape.

The EPROM method is a lot easier.

However, I will think about your suggestions. I am thinking about a method of recording CW and speech "standard" messages, such as "CQ NO CONTEST PLEASE DE SM0VPO", or "QUEERSHEAD CONTEST DE SM0VPO". The RaPi would be perfect for that

Another point is that the EPROM burner card is also a I/O device I can use for switching other things from my PC.

Very best regards from Harry - SM0VPO

Hi Harry,
EPROMs seem to be obsolete a bit. What about using a MCU with EEPROM, which would implement the sound file, A/D and D/A conversion and all the bells (literally!) and whistles? I think about PICAXE, Arduino, Teensy etc. If you are to redo nearly the whole project from scratch, it should give sense. These chips are dirty cheap and all you need to program them is a USB cable in some cases. (Some Arduinos require a JTAG programmer.)

VBR from Ivan

Thank you very much, Ivan. That is praise coming from you.

But it is easy to do anything if you are interested.

- I have to finish winding the transformer (and adding photo's)
- Trimming the antenna (when the temperature is plus)

Then the next project is a WeIrDe one.
- Maj-Lis wants a doorbell that plays the orchestra intro to Beethoven's 5th symphony.
- Logic, plus WAV in an EPROM, and an amplifier.
- That means I have to re-build my EPROM burner.
(the commercial one will not work on modern SW. The HB was lost in one of the moves. The BASIC source file is lost)
- and re-write some SW that works for burning only the data part of a WAV file to an EPROM.

Then of course writing / updating projects on the homepages. Perhaps I should think about early retirement. But I am only 69, so I really have a couple of years to go.

BR Harry - SM0VPO

Excellent work, Harry!! I am amazed!

VBR from Ivan

Hi all,
I have just updated the homepages with two new projects (and a revised old project).

My antenna experiments for small spaces
Transformer and choke design, including speaker transformers (to be updated shortly)

Both projects include simple formulas and on-line calculators :-)

Best regards from Harry - SM0VPO