We should have contests to design things.. (that could open minds and borders) - Page 1
Forum section: electronics / general

author: cdev
author_rank: Super Contributor
timestamp: September 14, 2017, 08:26:36 pm
content: There are a lot of really smart people here whose minds could enjoy a little competition.Why don't we have a little contest to see who can build the cheapest shortwave radio that can receive AM from the AM broadcast band up to 20 MHz. SSB/CW is not necessary.Also, it has to fit into a box the size of an Altoids tin (not including antenna) and the parts have to cost under $10, preferably under $5. The idea is a small shortwave radio for the poorest and most isolated people in the world.In certain countries, one country in particular, extreme small size, i.e. conceal-ability, is an important selling point.

author: buck converter
author_rank: Regular Contributor
timestamp: September 14, 2017, 08:34:52 pm
content: While I won't be entering, I have a few questions.How do you put a price tag on a coil you wind yourself, or point-point assembly? Does it have to be built entirely from off the shelf parts?

author: cdev
author_rank: Super Contributor
timestamp: September 14, 2017, 08:46:24 pm
content: No, and in fact, it would be best if it could be built from easy to scrounge parts such as common other items such as parts of discarded totally unrelated electronics, or garbage.Okay, let me level with you here. In the early 1960s, just as small, easy to concealtransistor radioswere becoming available, the Democratic Peoples Republic of Korea (DPRK) made all tunable radios illegal. They still are. And posession of one, is so illegal if somebody can not come up with bribes, it is sometimes treated as a capital offense.Poor people who have been captured and tortured for a few months are often trotted out to be publicly executed. All their teeth are broken out and rocks shoved in their mouths so they cannot curse the Great Suryong before they are put to death.These people whose crime may be as simple as watching a western soap opera (Desperate Housewives has come up in this context) or watching pornography or reading the Bible, speaking on a cell phone to relatives in the South, or listening to an illegal radio. All are considered to be treasonous crimes.Offenders are often publicly executed in stadiums where schoolchildren are brought in large numbers. They dress the victims all in white and read out their offenses. Then they shoot them in a manner calulated to maximize the terror effect on people who must watch it. They are shot with powerful anti-aircraft guns until their bodies are torn into shreds.How can this still be happening in the 21st century? All that needs to happen is for a lot of cheap tunable radios to be made available that are so small and so unrecognizable to an SSD agent looking for a "radio" - that there will be much less risk to having one. (They have a special department staffed with specialists whose entire job is driving around using sophisticated radiolocation equipment to locate people using cell phones and people using illegal radios and computers.The attached pictures are of a radio which was actually used inside of North Korea and brought with him when a recent defector fled the country. As you see its a PCB from a commercial radio that was likely discarded by a foreigner or brought in from China, which is right across a river that in dry times can be waded across, its been extracted and put into a box to conceal its function.

author: Cerebus
author_rank: Super Contributor
timestamp: September 14, 2017, 09:49:42 pm
content: Quote from: cdev on September 14, 2017, 08:26:36 pmI suspect that you've doomed the idea from the start by picking RF.Based on what I've seen discussed, off the top of my head I'd guess that folks hereabouts are about 70% digital, 20% analogue and a mere 10% RF.

author: chris_leyson
author_rank: Super Contributor
timestamp: September 14, 2017, 09:51:22 pm
content: Nice idea cdev, things like super regen and TRF receivers spring to mind although I never had much luck in getting anything to work when I was younger, maybe now that I'm older and wiser it wouldn't be so difficult. Whilst two or three transistor radios might look simple on paper they still present a difficult design challenge especially when you want coverage up to 20m and cost less than $10.

author: cdev
author_rank: Super Contributor
timestamp: September 14, 2017, 10:01:37 pm
content: I just used that as a hypothetical contest, the fact is, we're not taking contest here, so much as just tossing ideas around. I find that I sdo most of my SWL under 15 MHz (since we're not exactly at the peak of the sunspot cycle) Also, lower MHz easier to use repurposed transistors, say from discarded solar cells or lighting hardware.CFLs and LED lamps contain transistors..toroids, LEDs that could be repurposed as varactor diodes..(Northeastern)China with its abundance of cheap electronics is right across the Tumen or Yalu rivers.----The radio that the defector got may have been a radio from a hotel room music player which are disabled in some manner to not work. (see attached photos)

author: chris_leyson
author_rank: Super Contributor
timestamp: September 14, 2017, 10:05:42 pm
content: QuoteA valid point Cerebus, I'm job hunting at the moment and looking for a position that doesn't require C++ or C# and it pisses me off when I get emails like "25 hardware design enginneering jobs" and every single one is software requiring C++ or C#, seems there are too many agencies in the UK that don't know the difference between hardware and software, sorry just had to vent my spleen. But yeah, a bloody good point, demand for electronics engineers seems to have shifted more to software these days. Anyway it's still a good design challenge, thanks cdev.

author: cdev
author_rank: Super Contributor
timestamp: September 14, 2017, 10:42:31 pm
content: Its more than just that.Here you see four people two groups of two people from space. They are prisoners in a concentration camp. They have to always stay in groups of two. They might have been sent there because a family member listened to a big, easy to find radio and got caught. So the whole family, all three generations, were sent away to the mountains" they disappered into the night and fog as Hitler put it.The actual offender might have been executed, and their entire family sent away to essentially be slaves in these huge camps.This camp is still in operation. (I have met a survivor of it who lives in the US, and its not well known. He was once an officer in the North Korean secret police. He is a small businessman now. ) He's a very nice guy and its hard tioimage his prvous life, but ut was a fat, in fact his accouyt was one of the first defector talrNow lots of very sophisticated radios are so tiny they can never be found unless somebody knows where they are, but we still dont see HF shortwave radios the size of a coin. We have entire GPSs the size of a fingernail or a few grains of rice and entire cell phone modules the size of a thumbnail but still not cheap HF shortwave radios that can be hidden in a watch or a Kim Il Sung badge.

author: BrianHG
author_rank: Super Contributor
timestamp: September 15, 2017, 12:06:19 am
content: Having a contest to design things, Good.Designing a compact software radio, Ok, Good.Trying to make a contest to design a cheap all frequency radio to dump on North Koreans with their 'Entire families will be imprisoned/killed if one member gets caught with one.' or, 'Try to change such a regime by dumping all these radios easily upon them.'. Ok, I can feel the situation with DPRK's citizens. Their state is set up in such a way that you cant help the regulars out of this situation when those in power there are treated well off if they follow the set rules without question who do not want things to change. I can see why you want to change things there, but coming out with an electronic device solution here wont accomplish this goal and if somehow implemented, will hurt more than it saves. Unless you can come up with a cheap and safe way to transplant entire families and their associates out of the country all at once, and have a place to put all of them, and that all in such families actually want this and are agreed upon, I cannot find a gadget which can help. Your only option to effect change on DPRK citizens is to remove all in the power structure all at once. And again, with such a power vacuum, those that take their place might not be an improvement.Ok, back to the good idea of a design contest. How about a human whistle responding electronic switch. Micro-controllers are cheap enough today with enough CPU horse powers, built in ADC and built-in op-amps to have once listen for 4-6 patters to turn on-off 2 or 3 solid state switches. All do-able in a modern day 4$ DIP package PIC.

author: cdev
author_rank: Super Contributor
timestamp: September 15, 2017, 01:30:07 am
content: Experts (North Korean defectors) are all convinced that the information blockade is their Achilles heel and that getting more information into NK will cause irreversible changes, and bit by bit, peacefully, the regime will be forced to open up.A war would be a disaster and its inevitable that some incident will eventually set off a war if this continues. Millions of peiople could die directly from its effects and billions more, mostly children, would die of starvation all around the world just from the cost of food rising.people who had never even heard of North Korea and in many cases the United States.Truth matters. Those people have just lied so very much that the cost, the difficulty of maintaining the reality distortion field gets larger and larger.. Dont forgetl, they have to be kept in a state of ignorance. The economic cost of that is staggering.It gets ever larger and people know their lives are being stolen away. it wont take much in the way of truth to completely reverse the control the regime has over the country.Thats why they lock people up who know the truth about the outside.So, increased availability of cheap, small good HF radios really would change things. Its such a technologically achievable thing. Ya know......This is good:The Wall Which Crumbles: North Korea and the Outside Worldhttp://raskb.com/transactions/VOL86/VOL86-3.docx

author: helius
author_rank: Super Contributor
timestamp: September 15, 2017, 02:26:51 am
content: When you hear "the incident set off the war", it is a kind of newspeak hiding the fact that ministers and senators wanted to wage war all along and saw how war would benefit them or their donors. The responsible parties are not forced into war by accidents outside their control. They know exactly what they are doing.With respect to North Korea, war is very far off but some interested parties would like it to be closer. So they make a big noise about how the world is poised on a razor's edge, in hope of bringing it closer.

author: cdev
author_rank: Super Contributor
timestamp: September 15, 2017, 02:36:35 am
content: Yes, people don't get into those kinds of positions by being responsible.So,2 billion people would die of starvation.There would be a nuclear winter that would last years and during that time food would run out and cannibalism would become the norm.Like in that 2010 film "The Road" its a terrifying vision.This is why this has to end naturally. Radios are a natural process thats inherently peaceful.Nuclear weapons aren't.The world almost went to war in 1983. Luckily we didn't.http://nsarchive2.gwu.edu/nukevault/ebb533-The-Able-Archer-War-Scare-Declassified-PFIAB-Report-Released/

author: Nusa
author_rank: Super Contributor
timestamp: September 15, 2017, 02:49:55 am
content: Quote from: cdev on September 14, 2017, 08:26:36 pm100-year-old tech:https://en.wikipedia.org/wiki/Crystal_radio, cost from free to a few bucks, depending on how DIY you are. They usually were only aimed at the AM bands, but they could be designed for shortwave as well.Current tech: still pretty darn cheap.

author: Brumby
author_rank: Unknown
timestamp: September 15, 2017, 03:40:41 am
content: This thread is heading into territory that is going to get it locked.If this was meant to follow the "design contest" concept, then we need to get back to that - quickly.While discussing the potential use of a project within that scope is a valid consideration - parts of this thread have gonewaypast the design elements.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 15, 2017, 03:43:07 am
content: https://en.wikipedia.org/wiki/Foxhole_radio

author: cdev
author_rank: Super Contributor
timestamp: September 15, 2017, 04:05:36 am
content: This is a good article in the Guardian about the information blockade around North Korea.'How could our country lie so completely?':meet the North Korean defectors They send pamphlets and DVDs in balloons over the barbed-wire border. Can these defectors inspire others to make the same dangerous journey to the South?https://www.theguardian.com/global/2016/aug/27/north-korea-defectors-ian-birrell

author: Brumby
author_rank: Unknown
timestamp: September 15, 2017, 04:25:44 am
content: Quote from: cdev on September 15, 2017, 04:05:36 amStop. Turn around.Get back on topic or this thread will not last long.

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 15, 2017, 04:34:41 pm
content: ENOUGH TALK ABOUT DYSTOPIAN COUNTRIESor they'll end up closing this thread.To whomever suggested it, you don't need any type of fancy shcmany programmable rubbish to build a multi-way sound triggered switch. All you need is a CMOS/TTL decade counter and a 555 chip. A transistor (or another 555 IC) monostable would turn the mic input into a pulse that triggers the counter and the timer to trigger/reset until a certain delay when it would enable the output of all the pins (through an output enable pin or if needed transistors) to connect them to a bank of FETs which would switch on depending on which output of the counter was on.If you wanted to be more advanced you could even have a circuit that disconnects the ouptut again and keeps the selected FET on (RS latch chip) then pulses the counter until it reaches an unused output, so the next time it triggers it can reset itself with the next count back to 1 (switching the FETs off as it resets by having the output of the counter go through a diode to the reset pin so output 1 doesn't feed back, then the pulse just resets the latches to turn the FETs off). The output of the first timer would trigger the pulse circuit to start which would first reset the timer (which would enable a transistor to connect the pulse circuit to the counter), then start the count which would eventually disable the oscillator through the first pin that is not used as a main output (with the one after being the reset). It could still be tiny as a matchbox if you used SMD components and doublesided load.This is becoming a problem, where everyone thinks that everything must have programming and you need to know code to build stuff. Newsflash, you don't. I mean sure, if you are mass producing something and using a microprocessor is actually cheaper, then fine, but for home projects, learn to think in discreat logic. Your kid's first experience with electronics should be an old fashoned project kit with springs (or one of those kits with the plates and metal studs that click together, sold under the name Snap Circuits or Snap Kits), not a stupid Arduino or something.

author: Howardlong
author_rank: Super Contributor
timestamp: September 15, 2017, 04:51:02 pm
content: Coincidentally, about three or four years ago, I was approached by an NGO to provide clandestine radio receivers for use in the DPRK based on some other non politically motivated miniature designs I'd already done. While it would've been a potentially exciting and right-on thing to pursue further, I had other more lucrative opportunities in my in tray at the time. In view of what happened to Kim Jong-Nam at KLIA earlier this year, and that I also happen to pass through KLIA with some regularity, I'm now glad I let the opportunity go.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 15, 2017, 05:01:24 pm
content: I'd suggest something even simpler, like an LED flasher.Doesn't need a scope, doesn't need an antenna, doesn't need coils.What other constraints to make it interesting, though? Fewest parts? Most parts? Zany circuits? Best abuse of datasheet parameters, undocumented behavior?Tim

author: cdev
author_rank: Super Contributor
timestamp: September 15, 2017, 05:08:37 pm
content: What would that accomplish after the fact?Well, whichever NGO it was, I wish them luck. It seems as if there are lots of cheap SW receivers available in China already and some are small, the size of a small radio.There is no other country as bizarre and willing to break rules than North Korea. As far as they are concerned truth is stranger than fiction.I think it was a big big mistake for Bush II to take them off of the countries that support terrorism list. The problem is, nobody who has never dealt with entities like that understands that they will do literally anything to stay in power, evenkill millions of their fellow North Koreans.. (or one's own father, their Eternal President".)the scary thing is, the longer they stay in power the more other elites in other countries look to them and think, "if they can do it, we can do it too". (all sorts of things)And that is very bad.

author: Howardlong
author_rank: Super Contributor
timestamp: September 15, 2017, 05:14:30 pm
content: Quote from: T3sl4co1l on September 15, 2017, 05:01:24 pmI quite enjoyed participating in theFlashing Light Prizethis year. It had the right ingredients, in that the entry bar was low, and the rules were sufficiently well thought out, including the right amount of boundaries and vagueness, such that almost anything went.

author: Howardlong
author_rank: Super Contributor
timestamp: September 15, 2017, 05:26:29 pm
content: Quote from: cdev on September 15, 2017, 05:08:37 pmWell, I would imagine it is part of a propaganda war. I didn't investigate very far, but I am pretty certain that despite calling itself an NGO, A large part of its funding came from south of the border.QuoteThe specification was quite a lot smaller than one might think, and certainly neither the form factor nor the size of a "small radio". Think in terms of sugar cube sized.

author: cdev
author_rank: Super Contributor
timestamp: September 15, 2017, 06:15:39 pm
content: Was it a South Korean NGO or a US (or European or Australian) NGO?To tell you the truth, for all the noise they make about it, most of the governments really dont care about the situation, in fact some countries likely see it as helpful in helping them "justify" huge arms expenditures. (Extrapolating from the expressions of panic that I remember after the fall of the ex-USSR when they were terrified that there would be pressure to reduce military spending) Since they abandoned consumer electronics and other industries which didn't present the high profit margins, they basically committed themselves to an endless state of emergency and war. If peace were to break out...Well, frankly, I don't think they would allow that to happen. Do you? Its a similar situation to the one with democracy being incompatible with trade agreements that give "investors" guarantees that no law will "take their property" by changing policies that impact their profits without "just compensation" (lost expected profits in a impossibly profitable future) .This is what global capture looks like.Be silent, consume, die.

author: cdev
author_rank: Super Contributor
timestamp: September 15, 2017, 06:35:39 pm
content: Unfortunately, the situation in NK is not propaganda. If anything, the media in other countries softpedal the situation there. I mean, what could possibly explain it unless somebody made it an effort to learn about it .When you've heard literally hundreds of defector accounts from perhaps half as many people (Ive herd a number of defectors stories a number of times, read their books and met several of them) There is consistency, I've heard about the same situations over and over. as they have evolved, over a space of 20+ years, and now even can see the entire country from space, over a period of many years, we can see these places from space, one starts seeing it differently.I could probably give you at least a dozen or two examples of where the reality is likely much worse than what little has been reported in the media.The media goes to great lengths to not report certain kinds of news, this kind of news is at the top of the list of things they really dont want to report. People dont want to believe that people can be so evil to one another.All governments would prefer that the people as a whole not realize that governments are capable of behaving that way and that its not so difficult for them to descend to that level out of quite generic reasons they get themselves onto a path which just keep getting worse and worse and they just lie more and more to put off the day when it all falls apart into the future. People dont want to believe anything that challenges their world views. Even when those world views when viewed objectively are clearly questionable, people might have invested so much in their defining of themselves as this or that that the truth matters less to them than "being right" (even when they are actually wrong) So, a situation which appalls everybody from self-described communists to self described conservatives- (both of which groups have their good people and their bad) but you know what, when people start grasping the situation, sane people try to figure out what could be done, because its just a human tragedy beyond our power to describe taht just continues, like a black hole sucking millions of lives away. into a sort of half life or half existence..Way back in the early and mid 90s I thought things were bad there but saw it more as a sort of comical situation where I felt sorry for them.I had no idea how horrible it was until I was working with somebody, a scientist, who grew up literally within earshot of North Korea and he told me that people were dying there in large numbers of starvation and would do anything to get out, even be sold intoslavery in China so that they could simply eat and not die of starvation,.Because the government saw and framed leaving as a crime they would then try to shoot people trying to leave and indeed this was a daily occurance in my co-workers home town and he could hear the gunfire from his home. The river was not so very wide there. People would often wait until night and cross. But many would also die there in the winter.Many died trying to cross the ice cold or frozen river in wintertime and in the spring their emaciated bodies would wash up on the other shore. People were literally skin and bones.When he told me this, I knew he had to be telling me the truth. There was no reason to lie to me, we were kind of friends, we got into this conversation because while eating lunch in the lunchroom we were talking about our favorite movies and TV. (He also was able to watch North Korean TV which he described to me as bizarre, as they kind of shout the news.

author: Simon
author_rank: Unknown
timestamp: September 15, 2017, 07:00:20 pm
content: As you were warned 3 times, the thread is now locked!

author: EEVblog
author_rank: Unknown
timestamp: September 16, 2017, 06:03:51 am
content: Quote from: cdev on September 15, 2017, 06:35:39 pmcdev, please quit bringing your politics into this forum, it is not wanted.You have done this on several threads now and it will not continue to be tolerated.