A Crummy Commercial

Continued from yesterday: https://wb9kzy.blogspot.com/2026/06/morsemaster-ii-shaped-code.html   I did try the MorseMaster II sidetone on the solderless breadboard.  It actually works pretty well.  Here is an short pulse from the LM380 output with the RC filtering: It seems to me that I tried this circuit before but found it thumpy.  This time the thumping is minimal.  The two high pass RC pairs may account for this - I may have not used the spec'd parts before.  The only problem, noticed with headphones, is backwave.  There is a low level audio signal coming from the 555 chip which is running all the time - think of it as an on frequency QRP audio station which is key down all the time ! The backwave can be reduced by adding a series resistor to the headphones, I tried 180 ohms but more experimentation might help. One way around this problem would be to key the 555.  But that's not quite so simple since most of the 555 CPO circuits out there use a...

How many zillions of 555 based code practice oscillators are there beeping away ?  Probably quite a few - I remembered that my MorseMaster II project has one, previously mentioned here: https://wb9kzy.blogspot.com/2026/02/bad-cap.html     But the original MorseMaster II design by Mike, KJ4LN cleverly upgraded the 555, adding shaping to the waveform and RC filtering: So I thought about adding those circuits to my MorseMaster.  One interesting note: the 555 in the Morsemaster II runs continuously so really the circuits add keying, shaping and filtering.  The steady 555 current doesn't matter that much considering the power used by the microcontroller is fairly high. First, using a solderless breadboard, here are the full pulse and the zoom in on ramp up / down waveforms all at the the collector of Q4: . 4 ms rise time 8 ms fall time Next, here is the shaped square wave, with rise and fall zooms: That's about as far as I gotten so far, I'll add the filter and LM380...

Sometimes I'll get an inquiry on a kit: can you build it for me ? I've almost always answered: NO Why not ?  several reasons: I end up making choices on the enclosure and other parts that the buyer may not like. I am getting older, it's getting harder to build even through hole kits now - I just can't see as well. magnifiers help but being able to see well without optical help is really handy for building kits Building also takes time, even at $15 per hour that mounts up. As a kit seller I would be skirting the FCC regulations by selling something built which may or may not pass EMI requirements.  But a home kit builder doesn't have to worry about this.     Note that this isn't really true of unclocked kits, like the Keyall series.  And consider that if you do buy a built version of a Keyall with similar specs (a MOSFET SSR) a buyer will find they are fairly expensive in comparison to a Keyall HV.   Best Regards, Chuck, WB9KZY http://wb9kzy.com/ha...

I get an email from Nuts and Volts magazine weekly with some links to free articles (see the newsletter signup link at the bottom of the page): https://www.nutsvolts.com/ This article caught my eye recently: https://www.nutsvolts.com/magazine/article/some-simple-transistor-and-ic-circuits Here is the web site of the author, KE3FL:   https://www.cs.yrex.com/ke3fl/ The circuit that interested me was ramping the brightness of an LED up and down slowly to blink it.   I finally read the article, the circuit is a phase shift oscillator but at less than 1 Hz so the caps are big (electrolytics).  The author's video looks good although it's in subdued light.  I had a little trouble getting the circuit to play (didn't have a white LED at hand) so I tried simulating it with LTSpice: the green trace is out, the blue trace is sine this is the collector voltage Since it does seem to simulate I tried fiddling with it - got it to sustain oscillation by increasing the series res...

I didn't know about this: source:  https://www.youtube.com/watch?v=41U78QP8nBk But of course Arthur C. Clarke knew: source:  https://www.youtube.com/watch?v=c8N72t7aScY 1968 was 58 years ago and about the only thing we've accomplished above and beyond  2001: a space odyssey is that computers now can sing Daisy better: https://soundcloud.com/midnightalchemist7/daisy-bell-ai-evolution Or maybe (depending on your opinion) not even that ! Best Regards, Chuck, WB9KZY http://wb9kzy.com/ham.htm

Mentioned before: https://wb9kzy.blogspot.com/2026/05/saturday-miscellany.html The blue, city connect uniforms with Wisco on the front: seemed to be bad luck earlier in the season but Jacob Misiorowski, The Miz, was at it again: 95 pitch complete game,  1 hit, no walks,  shutout,  15 strikeouts, faced the minimum 27 Phillies. source:  https://www.youtube.com/watch?v=SvgEN_VsoIA An amazing game but I have to admit that I fell asleep listening at the end. Best Regards, Chuck, WB9KZY http://wb9kzy.com/ham.htm

Yes, I do still sell the AT-121 piezo sounder on the switch and parts page (this blog is called: A Crummy Commercial for a reason :) http://wb9kzy.com/switch.htm The AT-121 is 35 cents but they do look a little grungy and have short leads - I also still sell the larger CPE-6080 piezo at $2.50 each. However one thing the AT-121 has that the CPE-6080 doesn't have is a third, blue wire - this is a feedback area of the piezo.  It's used with this type of simple circuit shown on the datasheet: I realized that I never tried this circuit - when I've used the AT-121 in my own projects I always drove it via the red and black wires by a square wave from a PIC.  The blue wire was just clipped off.  But what are the advantages of the datasheet circuit ?  The main one that comes to mind is that it is simple but also since it operates at resonance, loud.  That volume is bordering on obnoxious at 9 volts but must be ear splitting at 28 volts. So anyway I did try the circuit on...