Super Non-Intuitive filter cascade - Page 1
Forum section: electronics / general

author: RJSV
author_rank: Super Contributor
timestamp: July 26, 2020, 05:36:55 am
content: Likely most readers expect Dodgy tech stuff to be largely useless. I disagree.David Jones' blog #1285 suggested design by schematic inspection. There, I agree.For an absolutely WILD speculation, consider a cascade of little digital audio circuit boards. In summary: each filter stage has a processor doing repeated START-RUN-RESET cycling (order of 1 mSec suggested).Viewing picture right to left is an example push button plus three audio output circuits. Up above is seen another example; a 'singing bird' having similar audio source.Now for the Dodgy aspect: Circuits are cascaded via DC power inputs, driven by previous circuit audio (AC). For example, if a first circuit issues 500 hz (hope) is the next, target processor should run for approx 1 mSec before getting yanked back to start-up Reset, as incoming DC pwr voltage drops down and goes into negative part of cycle.By variation of coding, cascades of processors can provide varied responses, to an input to the serial cascaded modules. Using above example, a processor can run, shorter or longer, depending on duration of input, thus forming a crude 'high-pass' function, or rather, a pass-thru of shorter input impulses.Now as to cascades, of two or three, clearly there should be seen 'some' kind of differences in overall output responses, according to micro-programming.Perhaps a useful notch filter function can be had, say program a 100 hz sinewave into each module. Or, how about trying a pulse, or two; occuring within time windows.Very strange, as each module processor only would run code for those short, repeated START/RUN/RESET time windows. Dodgy, yes, but I'd like to see...Thanks for attention. RJ in Hayward

author: MK14
author_rank: Super Contributor
timestamp: August 01, 2020, 09:10:34 pm
content: It could easily be just me.But I can't really understand this thread.Let's start with the title."Super Non-Intuitive" (ignoring the last two words for now). Doesn't really tell me what this thread is about.Ideally in a few words, or sentence. What is this setup suppose to be doing ?When and if it works.E.g. Is it a power supply, or bird sound simulator, or electrically adjustable (frequency) notch filter.What is it ?"Filter Cascade", doesn't really mean much to me. But I suppose it is multiple filters, connected together, one after the other.Also, schematics can help, as well.The picture seems to show a push switch. At least two unidentified COB's (Chip On Board), probably Chinese modules. At a guess, simple musical chime type of boards (e.g. for use in Door bell circuits). Two different sizes of Chinese, small loud speakers, and some other little module (possible a small amplifier or something), seemingly unconnected to the other things.

author: RJSV
author_rank: Super Contributor
timestamp: August 01, 2020, 10:37:51 pm
content: Here's a shorter answer, later I will post a schematic.A better title could say: " Cascaded COB Chimes make for a novel , unexpected time delay filter".When this set-up worked, hooking an audio output to the DC power input of a second 'chime' circuit, I started speculating, how(?) was that possible. I've sent audio thru a fixed 2 khz buzzer, successfully, so started thinking...One C.O.B. is marked "PT-313", has a surface mount transistor, probably speaker driver, and is used in a both forward power mode (toy puppy barks through the little speaker) but also passively tolerates a reversed supply (that be -3V). That way, this puppy toy can have two buttons on a wired hand control. First push button causes the toy to walk forward, while second push button causes the puppy to wag tail, barking (that be conventional +3V).Apparently, the arrangement saves wire costs, but the C.O.B. is not harmed, or diode protected (?). So first I had been trying some audio outputs for direct connection to an LED, no resistor (risky). That worked, and I measured about 700 mV AC, relative to ground. Being an 'H' output, this AC voltage went up, to 1.3 V when both speaker output wires were measured, against each other (both outputs switch, in an 'H' driver.) Ok, then somehow I tried to see what would happen if I tried to power that barking puppy C.O.B. and it served to pass through the audio! That is, a cascade of a bird chirp audio circuit to 'power' a next puppy bark circuit actually works: You hear chirping even though expecting barking sounds.Theory was, the processor had not yet begun running enough for barking, but the output transistor served to respond to the (unconventional) application of AC to the DC supply. Kind of a supply ripple.Of course this could be done in software timing, a conventional way to go, but I'm doing salvaged parts exploration, and this has no added components, to get the little 'dog' toy to chirp like a bird.The cascades of two circuits does not work when single sided audio output is tried: remember, that was 700 mV AC. So I pondered how to best cascade the C.O.B. pair, as grounds cannot be common.But also I realized that cascaded pair has a time-delay filter aspect. Suppose your circuit will send out significant audio level, only after 300 milliseconds. Any short lasting input will be blocked, while an AC waveform with positive half of longer duration can make it through. But I STILL expected barks, not short chirps.I hoped to later ask eeVblog: What size capacitor would one of those epoxy covered ICs include, under there? Does the processor execute code, yet, or stay in power up reset?So I have a couple directions here:. One way is study of useful salvage, no changes. The other is with my own written code / compiler/ burner to experiment with the whole set of possible cascaded circuits.More tomorrow...

author: MK14
author_rank: Super Contributor
timestamp: August 01, 2020, 10:59:12 pm
content: Thanks.That does make more sense than the original post.In answer to your upcoming/future question ("eeVblog: What size capacitor would one of those epoxy covered ICs include, under there? ").My educated guess (but it could be wrong), is that there is no or very little in the way of capacitors, included under the COB (if it does have any, they will be small, very low valued ones, on the IC).COB, usually means extreme, bare bones (lowest possible) cost. Otherwise, it would probably be packaged in a real/proper IC case, such as a SOIC (other surface mount options are possible as well), surface mounted one, with thin leads sticking out of it.Similarly, the integrated circuit chip die (tiny cut up piece of silicon, under that black plastic circle, i.e. COB), needs to be as small as possible. Because the bigger it is, the more expensive it is.Putting capacitors on IC chips, needs lots of area (if it has a significant/bigger value), still only has limited/small values and is something you want to avoid doing, because it is very expensive, as it can use lots of silicon IC die area.If the circuit needs a capacitor(s), then it is usually much cheaper, to just specify it as being needed, EXTERNAL/outside the chip (COB), on the PCB somewhere.

author: RJSV
author_rank: Super Contributor
timestamp: August 02, 2020, 10:24:04 pm
content: Here is more info and diagrams for clarity describing what uses some various TOY audio C.O.B. circuits can have, with multiple 'cascades'. (COB is those little epoxy covered micro-controllers).First up, a TOY piano has one octave for use. Seen are pcb edge contacts, originally this drug-store toy had a foot-mat keyboard but the PICT shows a simple jumper wire for sounding one of the piano notes.Next, a quick layout involving two circuits cascaded, to drive a loudspeaker. By the way, I often place a 10 ohm resistor in series with the speaker for less volume.Lastly, here, is an actual piano note waveform: You can see a second harmonic asserting along the sine-like fundamental.Now, previous discussion mentioned other audio sources, a 'Dog Bark' audio and 'Bird chirp' audio, all with similar AC voltages, around 700 mV relative to ground or minus pwr, and 1.3 volts AC in a 2 wire H bridge output.The 'bodgy' here is the unconventional cascade layout where positive swings of the audio will briefly power the next in line device. Mainly, no damage is done by a reasonably small pwr voltage being backwards briefly, although speculation says the controller C.O.B. is going to stop running any code steps.The piano waveform drawing shows some areas where I've speculated the code is running. Typically such code first has a delay routine, giving other hardware time to settle, perhaps 300 micro-seconds, as, word is, no bigger cap.s are present to hold a power up reset state for long.I estimate a bird chirp waveform might have an interval of (only) 10 to 20 micro-seconds processor run window, in which case each toy C.O.B. circuit is really only doing modulation, of an audio output transistor.This design / use task is highly speculative but really FUN, for me. As the box says: AGES 3 +(For related, please see blog post on 'Multiple Module Connection Box' in PROJECTS section of eeVblog.Thanks, RJ in Hayward

author: MK14
author_rank: Super Contributor
timestamp: August 03, 2020, 03:02:13 pm
content: Ok, thanks for the schematic and extra details.Now, I better understand what you were doing.Although to some extent, it is interesting, to perform such experiments. It is really rather limiting. Because there is only a very limited number of ways, you can connect two modules together, like that.E.g. Module A, powering Module B to Speaker.Or Module B, powering Module A to Speaker.I guess you could have some fun, doing that for a period of time.But, if you don't mind me suggesting. What should be much more interesting, and give you a much wider range of experiments. Would be to get hold of an electronics kit and/or electronics components and/or Programmable Microcontroller development board (e.g. Arduino clone).Or, even emulators and/or electronics simulators, Such as the free, and yet powerful, LTSpice. If you have access to a PC, and don't feel like spending money on stuff, yet.That would then give you a huge range of experimental and learning opportunities.These 'beeping/musical' things you seem to be using, won't really let you get much work (especially as regards variations), done.Also, the 'Products » Dodgy Technology', is not the best of places to post things like that. Maybe Projects or Beginners sections, would get you more fellow EEVBLOG forum user views.

author: RJSV
author_rank: Super Contributor
timestamp: August 03, 2020, 08:32:21 pm
content: Thank you for thoughts, I will check things out further. All due respect; Been there, done that. In 1978 I assembled a self-designed A to D audio sampler and circular RAM bank that clocked sampled values in while simultaneously clocked sampled out at twice the (input) rate. That output sound, via D to A had sound up an active, for guitar effects.That maze of wires and TTL IC's was a mess and scrambled my TV screen, on RF broadcast TV then. So I had good exposure as a hobby experimenter. To a minor extent, I built simple OP amp circuits, such as audio X ten amp, again for guitar pedals. My love of coding took me that direction. I can respect a good hardware PRO, rare to find.Right now, the project(s) have a resemblance to 'Steam Punk developers, maybe more ignorance than expertise. My tasks have a huge component of time management and health / financial shortcomings.(You don't t want to get sick, in Silicon Valley.)Partially, I've been edging up to a project / build, of a self-driving Grocery Cart. My local town is lacking full sidewalks, making auto drive (carts) a challenge.I've joked that should hyjack a Prius, putting computer in my motorized cart, for sending to store. But that's illegal. Seems un-focussed, but you'd be surprised.

author: MK14
author_rank: Super Contributor
timestamp: August 03, 2020, 09:44:31 pm
content: I'm not really into 'Steam Punk' stuff.>>"In 1978 I assembled a self-designed A to D audio sampler and circular RAM bank that clocked sampled values in while simultaneously clocked sampled out at twice the (input) rate. That output sound, via D to A had sound up an active, for guitar effects."Wasn't the preferred method then, to use charge coupled devices (CCD), to do things like that ?But, maybe CCDs, were not suitable to use, with that specific design technique, you were using.>>"self-driving Grocery Cart"Wouldn't that be potentially dangerous to other people, unless you have a highly experienced team of safety engineers, to design it, so that it could be safe. Then there are all the approvals, you would probably need.>>"I've joked that should hyjack a Prius"Do you mean, 'Tesla' ?For the Auto Pilot, machine/computer stuff.

author: RJSV
author_rank: Super Contributor
timestamp: August 03, 2020, 11:22:07 pm
content: Thank you, MK14, for your patient and detailed attention! I value that, and feedback, good or bad, is part of why I'm on eeVblog, finnally: just upgraded to smart phone last month. Whew, you've got me using Wikipedia, just to keep up.Yes, I was referring to TESLA self-navigating electronics, thanks. My intent is to ask at Alameda County, if I can apply for a 'monitored testing' permit, that meaning that I would be there, within 20 feet during active trials, down the hill 1/2 mile and back. Using a 100 watt 24 volt scooter motor, the cart is small and (largely frivolous) has various 'TECH' looking crap showing, that's one 'steampunk' avenue. I use the local Tap Plastics outlet to obtain futuristic styling.Heck, ask any marketing dept. They often welcome upgrades in presentation or basic looks...I often get comments from friends that say: "That's really cool...but what is it??".If anyone cares to, and sorry to diverge for a few seconds, can always look up my patent application for a teaching system, please see:USPTO 'pair' has application, 2002:BASTIAN, titled "Methods and Components for Mechanical Computer".I put a lot of focus on making (that) 7 ft tall system look modern and appealing. Difficult to pull out of the 2002 archives, but you can get plenty of details there.PTO office examiner didn't like that, but later USPTO submissions actually quoted (my) stuff as 'prior art'.Sorry to change topics.

author: MK14
author_rank: Super Contributor
timestamp: August 04, 2020, 12:25:58 am
content: Assuming I found the right one (Patent), that is really long, at 166 pages. From a quick read/skim through, there are some interesting features, and some possible mistakes.E.g. Interesting concept, to have mechanical XOR, exclusive-or gates.Also, interesting that it brings up a list of Microprocessors/MCUs, available at the time.But, the initial list (4004, 8008, 8080), seems to be missing the Intel 4040.Also, it talks about sky high, computer purchase costs, to program those early chips. But, there was the (cheaper), option of using time-share links, to potentially save money. But that could turn out expensive as well, if used lots of times.It does look steam-punky, I see what you mean.It looks like it must have taken an incredibly long period of time to design, document and create the patent. Perhaps 9 years ?Whoever wrote the patent (I think it was mostly or fully done by you), they have done a really good, and detailed piece of work, on it.It's interesting, to make a computer, mechanically.The patent even mentions and gives examples, of Basic Source Language.I can link to it, but I'm not sure if you want me to ?As regards the autonomous scooter."My intent is to ask at Alameda County, if I can apply for a 'monitored testing' permit, that meaning that I would be there, within 20 feet during active trials, down the hill 1/2 mile and back."Yes, that would be the way to get permission. Hopefully the speed would be small, it would have sensors that can detect if it is about to hit something, and if it does, it immediately stops.Also, hopefully you will have some kind of device(s), which will very reliably allow you to stop it (remotely), if it mis-behaves.

author: RJSV
author_rank: Super Contributor
timestamp: August 04, 2020, 04:03:36 am
content: Yes, I am ok with anyone using links, to the abandoned patent application seen above. Any further details, on the binary computer I think best if I soon start a separate POST probably in the vintage computer topics section. In principal, the steel ball and moving paddle constituted a BASE ONE math operation: The moving ball as a 'mass impulse' means, with positional encoding... Thus the moving (falling) ball embodies an inherent self-clock.I had, subsequently, moved up the organizational chain, after filing that jumbo patent. Look for a post later, probably in VINTAGE COMPUTER topics. The decimal system is where the 'cool' sh*t' really gets rolling. I think I can put together an essay on the 10 digit 'RAM' block, of approx size of a basket ball.You could run decent code using 100 digits of RAM storage. Both system types are physically BASE ONE, I swear! (Hint: Binary or Decimal systems build the BASE up by concatenating base-one impulses using dedicated 'positional encoding'.- RJHayward

author: MK14
author_rank: Super Contributor
timestamp: August 04, 2020, 06:07:20 am
content: Yes, a new thread in the VINTAGE COMPUTER section, makes a lot of sense.Here is the link (which has a downloadable PDF file):https://patents.google.com/patent/US20030172205A1/enThe fact the machine is mentioned as being (or compared to), a Pinball machine, also sounds interesting.As is, watching the 'cascade' mechanism lift up the balls.

author: RJSV
author_rank: Super Contributor
timestamp: August 04, 2020, 06:34:08 pm
content: Comments as I close out my post:My favorite is shown in FIG. 32, 33a, 33b on that Google portal. The clock free-fall regulator is another fave, pls text towards end of doc."No good deed goes unpunished": Wonder who said that? For a time, I used (the filing priority) as de-facto legal protection; a springboard for further development of some futuristic looks and advanced functions. Readers likely recall: At that time I was (almost) ready to file with USPTO, September 10th 2001. But still had some loose ends, that delay kept me out of a messy situation, as any mail was disrupted for a time...Basically, this document would be split up, at least 3 separate 'clean up' re-filing. Funny thing, like oil and water, I could never drum up significant interest in museum grade construction!For the next post, see fig 13, I will provide some drawings, having 'Pin Stripe' looks showing an expansion of the fig 13 devices. (Not in this thread)

author: MK14
author_rank: Super Contributor
timestamp: August 04, 2020, 07:36:28 pm
content: Ok, well I will continue it in the next thread, as well.Thanks.