Microcasting Color TV By Abusing a Wi-Fi Chip (hackaday.com)

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Microcasting Color TV By Abusing a Wi-Fi Chip (hackaday.com)

Posted by timothy on Tuesday March 1, 2016 @06:24AM from the why-does-the-chip-keep-coming-back? dept.

szczys writes: The NTSC standard has effectively been replaced by newer digital standards, but most televisions still work with these signals. This can be done through a composite video connection, but more fun is to broadcast video directly to your television's analog tuner. This is what cnlohr has been working on, using a lowly ESP8266 module to generate and transmit the color TV signal. This board is a $3 Wi-Fi module. But the chip itself has a number of other powerful peripheral features, including I2S and DMA. This hardware makes it possible to push the TV broadcast out using hardware, taking up only about 10% of processor time. Even more impressive, cnlohr didn't want to recompile and flash (which is a relatively slow process) during prototyping so he used a web worker to implement browser-based development through the chip's Wi-Fi connection. Speaking of chip-abuse in the interest of hyperlocal signal propagation, reader fulldecent writes to point out a project on GitHub that "allows transmission of radio signals from a computer that is otherwise air gapped. Right now this could be useful for playing a quick tune or for pranks. But there are more nefarious uses as this could also be used to exfiltrate information from secure networks."

63 comments

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chip 'abuse' !? by sittingnut · 2016-03-01 06:38 · Score: 2

'abuse' ?!
1. Re:chip 'abuse' !? by Anonymous Coward · 2016-03-01 07:02 · Score: 1
  
  "ab-use" to use something in a manner not originally intended
  overclocking the I2S fifo to the megahertz range is clearly "ab-use" unless you have some sort of miracle eardrum that can vibrate at that frequency
2. Re:chip 'abuse' !? by sexconker · 2016-03-01 07:12 · Score: 1
  
  Well, it's spectrum abuse at least. You're explicitly not supposed to be using that spectrum for this shit.
3. Re:chip 'abuse' !? by ArchieBunker · 2016-03-01 08:50 · Score: 2
  
  Nobody else appears to be using it.
  
  --
  Only the State obtains its revenue by coercion. - Murray Rothbard
4. Re:chip 'abuse' !? by sjames · 2016-03-01 09:12 · Score: 1
  
  Actually, abuse explicitly includes that the use is bad or harmful.
  If the chip fails in a few minutes of that, it is abuse.
5. Re:chip 'abuse' !? by Anonymous Coward · 2016-03-01 11:47 · Score: 0
  
  abuse explicitly includes that the use is bad or harmful.
  Or that it's being used in a way that's not intended -- such as drug abuse or abuse of authority. The connotation is negative, sure, but it's also negative with "exploit" -- a near-synonym in the tech world.
  Now tell me how it's not "hacking" if you don't take away any code.
6. Re:chip 'abuse' !? by sjames · 2016-03-01 12:39 · Score: 1
  
  Hacking in that context has never meant removal of anything but a problem or task. Though hack in that context can mean solving a problem through using things in a positive but unintended way.
  Drug abuse very much is meant to identify that use as bad. Your values may vary but among those who don't see it as bad I have only heard the word abuse used sarcastically or ironically. Abuse of authority is most certainly meant to indicate that that unintended use is bad.
7. Re:chip 'abuse' !? by Ol+Olsoc · 2016-03-01 13:02 · Score: 1
  
  Actually, abuse explicitly includes that the use is bad or harmful.
  If the chip fails in a few minutes of that, it is abuse.
  Except for self abuse. Then it's just fun.
  
  --
  The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
8. Re:chip 'abuse' !? by sjames · 2016-03-01 13:26 · Score: 1
  
  Sorry to hear about your failure problem. There are drugs that might help that.
9. Re:chip 'abuse' !? by BoogieChile · 2016-03-01 15:27 · Score: 2
  
  > [heavily paraphrased] Running the program on an Apple MacBook Air (13-inch, Early 2015) uses the _mm_stream_si128 instruction to write through to a memory address, causing electromagnetic radiation to be emitted from the computer at 1580 KHz.
  > By tuning an AM radio tuned to this frequency, you should hear "Mary had a Little Lamb" played over and over.
  ...Seems a perfectly cromulent use of the word.
10. Re:chip 'abuse' !? by Ol+Olsoc · 2016-03-01 15:40 · Score: 1
  
  Sorry to hear about your failure problem. There are drugs that might help that.
  Now now, A sense of humor, so lacking in many these days, is a great help in getting through life happily. And alas, there are no drugs for that.
  Well, maybe Nitrous oxide.
  
  --
  The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
11. Re:chip 'abuse' !? by Anonymous Coward · 2016-03-01 20:46 · Score: 0
  
  Actually, abuse explicitly includes that the use is bad or harmful.
  If the chip fails in a few minutes of that, it is abuse.
  Fail within minutes?
  The chip isn't supposed to fail for decades, even up to a century if handled properly and protected.
  Running it out of spec. can make it fail within a few years.
  Why do you require it to fail within minutes to call it abuse?
12. Re:chip 'abuse' !? by sjames · 2016-03-01 21:08 · Score: 1
  
  It's just an example, there's not a true bright line there since even run within specs, the failure prediction is just an average.
13. Re:chip 'abuse' !? by Anonymous Coward · 2016-03-02 12:02 · Score: 0
  
  The root of the term "Hacking" hails from hacking at a wooden stump with an axe.
14. Re:chip 'abuse' !? by sjames · 2016-03-02 12:26 · Score: 1
  
  Sure. But since the chip isn't made of wood, we can guess that one of the other shades of meaning it evolved to applies.
  One day, abuse may evolve to lose it's explicitly negative meaning and then you'll be correct. But not today.
AND THUS DUMONT IS REBORN! by Anonymous Coward · 2016-03-01 06:40 · Score: 0

All hail Captain Video!
all life matters breakout continues by Anonymous Coward · 2016-03-01 06:41 · Score: 0

spirit of creation is color blind? it does supply more than enough of everything we need to take care of each other without any insidious personal gain motive... hand in hand WE stand... cease fire.. in the moms we trust...
Shades of Don Lancaster's "TV Typewriter"! by jeffb+(2.718) · 2016-03-01 06:45 · Score: 3, Interesting

This is beautiful. It takes me back to my late teens, building out TTL divider chains and 2K CMOS static RAMs to make a higher-resolution (30 rows of 100 characters) alphanumeric display for the TRS-80. Maybe I won't toss that 1970s 13" color TV just yet...
1. Re: Shades of Don Lancaster's "TV Typewriter"! by Anonymous Coward · 2016-03-01 11:23 · Score: 0
  
  I can only imagine playing Frogger in "custom" HD...
2. Re:Shades of Don Lancaster's "TV Typewriter"! by Snotnose · 2016-03-01 12:39 · Score: 2
  
  Don't forget the games that used white noise to generate a soundtrack. Tune a radio to an unused station, fire up your game, and voila! Sound!
Outstanding! by CaptainLard · 2016-03-01 06:47 · Score: 5, Insightful

This is the coolest little hack I've seen on /. since...probably dice bought it. More of this please!
One minor quibble, no need to editorialize the "POTENTIAL SECURITY VULNERABILITY". We already know everything is a weapon for terrorists these days. How about instead of "speaking of chip abuse" we have "speaking of $3 computers with tons of hidden functionality"?
1. Re:Outstanding! by sunderland56 · 2016-03-01 06:53 · Score: 4, Informative
  
  Agreed - cool hack.
  There *should* be a big, huge warning, though - about violating FCC rules. The hack broadcasts on restricted frequencies; replicate at your own risk.
2. Re:Outstanding! by Anonymous Coward · 2016-03-01 06:56 · Score: 0
  
  Check out hackaday.com, it's where this came from.
3. Re:Outstanding! by Anonymous Coward · 2016-03-01 06:58 · Score: 0
  
  Agreed - cool hack.
  There *should* be a big, huge warning, though - about violating FCC rules. The hack broadcasts on restricted frequencies; replicate at your own risk.
  your car's starter motor violates FCC rules when the brushes get old, so you too will join the others in the gulag for violating the rules
4. Re:Outstanding! by Obfuscant · 2016-03-01 07:07 · Score: 5, Informative
  
  your car's starter motor violates FCC rules when the brushes get old, so you too will join the others in the gulag for violating the rules
  The phrase "intentional radiator" has a significance here. Google it if you are confused.
  It would be a good question to research if this intentional radiator met the limits of a Part 15 device, like the unlicensed AM and FM broadcast transmitters that you can buy or build.
5. Re: Outstanding! by Anonymous Coward · 2016-03-01 07:42 · Score: 0
  
  Absolutely! Now if only I hadn't ebayer the cool old 50s TV I used to own...
6. Re:Outstanding! by SeaFox · 2016-03-01 08:05 · Score: 1
  
  The hack broadcasts on restricted frequencies; replicate at your own risk.
  Same as taking an FM transmitter meant for linking to a personal vehicle stereo and hooking the antenna to an amplifier.
7. Re:Outstanding! by I4ko · 2016-03-01 08:32 · Score: 1
  
  Well it is nice, but it is late. 11 years ago we (one person at least) knew how to transmit both analog and Digital, yes digital with a homebuilt equipment [bellard.org]
8. Re:Outstanding! by ArchieBunker · 2016-03-01 08:54 · Score: 2
  
  The FCC doesn't care anymore. You have to be interfering with commercial stations for months before they do any investigating. I still hear people talking on the CB with illegal amplifiers. Even if they do fine you, you can appeal it down to a fraction of what they asked.
  
  --
  Only the State obtains its revenue by coercion. - Murray Rothbard
9. Re:Outstanding! by tlhIngan · 2016-03-01 08:54 · Score: 2
  
  Same as taking an FM transmitter meant for linking to a personal vehicle stereo and hooking the antenna to an amplifier.
  Actually, no. The FCC has excluded low-power FM transmitters from requiring licensing, thus making those little FM transmitters for your car perfectly legal. The FCC basically limits their power to 200 feet or less range (the FCC measures output not by mW, but by complete system, so if you have a 200W transmitter with a piss-poor antenna that gives you 200 feet max, that works. Same goes for a 10mW transmitter with efficient antenna).
  XM Sirius Radio (back when it was XM Radio) got in trouble because their FM transmitters were way more powerful than that.
  But no, FM transmitters have an exception as long as it's limited range. The transmitters still need FCC certification as they are intentional radiators, but license to operate and broadcast on the AM/FM band is not required for low-power FM.
10. Re:Outstanding! by sunderland56 · 2016-03-01 09:13 · Score: 3, Informative
  
  It would be a good question to research if this intentional radiator met the limits of a Part 15 device, like the unlicensed AM and FM broadcast transmitters that you can buy or build.
  FCC OET Bulletin No. 63, October 1993:
  With the exception of intermittent and periodic transmissions, and biomedical telemetry devices, Part 15 transmitters are not permitted to operate in the TV broadcast bands.
11. Re:Outstanding! by Toshito · 2016-03-01 10:29 · Score: 2
  
  If you're doing it from your mom's basement (like any self respecting slashdoter should) the signal will not be powefull enough to get outside.
  
  --
  Try it! Library of Babel
12. Re:Outstanding! by Anonymous Coward · 2016-03-01 11:07 · Score: 0
  
  So, as long as it is intermittent, it is fine.
13. Re: Outstanding! by Anonymous Coward · 2016-03-01 11:24 · Score: 0
  
  Keep in mind that intermittent transmissions are specifically *not* broadcasts, which are defined (roughly) as sustained transmissions to no particular endpoint. The FCC also explicitly bands the amateur broadcast of music for any purpose, with the sole exception of repeating an amateur transmission from a space station that happens to include some music.
14. Re: Outstanding! by Anonymous Coward · 2016-03-01 11:25 · Score: 0
  
  that's what my car mechanic keeps telling me
15. Re: Outstanding! by sunderland56 · 2016-03-01 11:41 · Score: 2
  
  The FCC also explicitly bands the amateur broadcast of music for any purpose
  You are talking about licensed Amateur Radio here, FCC Part 97. That is completely different from unlicensed low power transmissions under Part 15, which have no such restriction. Amateur transmissions are prohibited in the broadcast television frequencies.
  The plug-in dongle to transmit from your iPod to the FM radio in your car, for example - a Part 15 device, and it clearly does allow music.
16. Re:Outstanding! by Obfuscant · 2016-03-01 11:42 · Score: 1
  
  FCC OET Bulletin No. 63, October 1993:
  Do you notice that this bulletin is 23 years old, perhaps?
  47CFR15 has an entire subpart H that deals with "white space transmitters". That subpart covers an AWFUL lot of Part 15 transmitters that are none of intermittent, periodic, or biomedical telemetry, but live in the TV broadcast bands, all unlicensed.
  The times they is a changin', Jeb. Next thing you'll know, they'll have phones that you don't need to jingle Mable to get you connected to someone else. What is the world coming to?
17. Re:Outstanding! by mikael · 2016-03-01 11:46 · Score: 1
  
  That sounds like the perfect theme for a comedy sci-fi movie: FCC gulags spread across the country. Inmates detained for reasons ranging from failing to maintain starter motors, keeping old washing machines and electric drills, refusing to hand over old multi-sync CRT monitors.
  
  --
  Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
18. Re: Outstanding! by Obfuscant · 2016-03-01 12:02 · Score: 1
  
  Keep in mind that intermittent transmissions are specifically *not* broadcasts, which are defined (roughly) as sustained transmissions to no particular endpoint.
  
  Along with your confusion between the amateur radio service (Part 97) and unlicensed operation (Part 15), you have an unusual definition of broadcast. Broadcasting is not defined by it's "sustained" nature, but by the intended recipients.
  
  with the sole exception of repeating an amateur transmission from a space station that happens to include some music.
  This, too, is not correct. 47CFR97.113(c) permits the retransmission by amateur operators of:
  
  communications, including incidental music, originating on United States Government frequencies between a manned spacecraft and its associated Earth stations. Prior approval for manned spacecraft communications retransmissions must be obtained from the National Aeronautics and Space Administration. Such retransmissions must be for the exclusive use of amateur radio operators.
  Note that these transmissions are not "broadcasts" because they are not intended for the general public.
  As to the source of the music, there are many "space stations" as defined by 47CFR97.207, but there is no exemption for music for those stations. It is solely for incidental music from or to manned spacecraft on US Government frequencies. AMSAT cannot transmit music on amateur frequencies, even though such a satellite is a space station.
19. Re:Outstanding! by Anonymous Coward · 2016-03-01 13:33 · Score: 0
  
  I completely agree. I've done my share of weird hardware/software hacking over a span of over 40 years, and this guy drops the mic.
20. Re:Outstanding! by sunderland56 · 2016-03-01 13:45 · Score: 1
  
  This is slashdot, not fark. Some minimal level of civility is common.
  White space devices need type approval (and are quite complex, generally needing an internal GPS and a database). The "unlicensed" part means that the end purchaser does not need a FCC license to operate, not that the device doesn't need to be tested and approved prior to sale.
21. Re:Outstanding! by CaptainLard · 2016-03-01 15:18 · Score: 1
  
  Wow *sniff. Never in my wildest dreams did I think the conversation would end up this way *sniff *sniff. Arguing regulation sub-parts and outdated FCC bulletins. (wipes tear). Does /. really have a chance of going back to the "good" ol days?
  And yes I read a few paragraphs of the eCFR to see what yall are on about. Thanks for providing a link to true entertainment!
22. Re:Outstanding! by Anonymous Coward · 2016-03-01 22:00 · Score: 0
  
  Some minimal level of civility is common.
  You must be new here.
23. Re:Outstanding! by Megane · 2016-03-01 23:48 · Score: 1
  
  It also isn't much of an "intentional radiator" if the signal is confined to a properly shielded cable. I didn't see any details of how he connected the RF signal. And you can certainly buy RF modulators that generate an analog NTSC signal on channel 3 that you could theoretically hook up to an antenna. The FCC really doesn't care unless it transmits with significant power or it's a mass-produced device that causes interference.
  
  --
  #naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
24. Re:Outstanding! by Obfuscant · 2016-03-02 07:51 · Score: 1
  
  This is slashdot, not fark. Some minimal level of civility is common.
  I was quite civil. I used humor to point out that relying on a 23 year old FCC bulletin instead of the 2106 regulations is a bad way to determine what is and is not legal.
  
  White space devices need type approval
  
  Are you going to be selling or manufacturing these low power TV transmitting devices? Was that question uncivil?
  
  not that the device doesn't need to be tested and approved prior to sale.
  And if the device is never sold?
Check the FCC regulations first by davidwr · 2016-03-01 06:58 · Score: 4, Informative

If you are relying on Part 15 FCC regulations, be sure to read them first. Using a device in a way not contemplated by the manufacturer can turn your "approved" device into a "home-built transmitter [that is] not for sale" which puts the onus entirely on you to comply with the rules.
Having said that, if nobody complains, then you almost certainly won't be hearing from the FCC, and even if you were to use a device "as intended" and it caused harmful interference, you are still required to cease using it.
https://www.fcc.gov/Bureaus/En... has an interesting item on page 7:

With the exception of intermittent and periodic transmissions, and biomedical telemetry devices, Part 15 transmitters are not permitted to operate in the TV broadcast bands.
I guess that means if you are only going to transmit "intermittently" or "periodically" then this is fine, but it's probably not okay to use this for your home-security system that runs 24/7.
Channel 3 is in the 54-70MHz band, which is okay but only at very low power, 100 microvolts/m measured at 3 m away ("quasi-peak").
It is almost certainly legally safe to use this over low-VHF channels over coax rather than "over the airwaves," and you'll probably get a stronger signal to boot. But it won't be as much fun.
There may be some opportunity to use this under other parts of the FCC rules, such as part 18 (industrial, scientific, and medical) and, on applicable frequencies, part 97 (amateur radio license-holders only, and only in ham bands, and even then NTSC is not an acceptable "mode" in many bands).

--
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
Okay, that document was very out of date by davidwr · 2016-03-01 07:05 · Score: 2

Oops, I just got egg on my face. That document is 20 years old. Please consult the current FCC Part 15 regulations, which should be widely available.
My Google-fu is obviously not working well today.

--
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
1. Re: Okay, that document was very out of date by ModernGeek · 2016-03-01 08:12 · Score: 1
  
  You can tell the slashdot crowd has matured when it starts to look up the rules pertaining to something when a hack is posted. While it may be for the better, I like the days when we could push the bounds without question. I don't think the new kids these days are pushing the limits anymore.
  Whatever happened to pirate radio?
  
  --
  Sig: I stole this sig.
2. Re: Okay, that document was very out of date by drew_kime · 2016-03-01 08:38 · Score: 1
  
  I don't think the new kids these days are pushing the limits anymore.
  Whatever happened to pirate radio?
  They put Kevin Mitnick in jail for 5 years for hacking the phone system.
  
  --
  Nope, no sig
excuse me for pointing this out by Anonymous Coward · 2016-03-01 07:11 · Score: 1

but doesn't radio transmission implicitly imply that the devices are air gapped....
oh well, anything to keep the sheeple busy running around and wondering. Better than them coming after you and tearing you a new one.
good grief.
1. Re:excuse me for pointing this out by bws111 · 2016-03-01 07:31 · Score: 1
  
  Wifi uses (wait for it) radio transmission. You would have to be a complete moron to consider a device with active WiFi to be 'air gapped'. Even more shocking (to you) is the fact that even wired devices can also have radios!
  The remainder of your post appears to have been written by a random word generator.
Didn't work for us in the late 1970s by swb · 2016-03-01 07:28 · Score: 3, Funny

I forget why, but we had an RF modulator, possibly to connect some early VHS deck to a TV. We also had a video camera and a giant antenna on the roof of our house, and we thought it would be awesome to make our own local channel 3.
Try as we might, connecting the RF modulator to the TV antenna did not allow our broadcast to be received by anyone in the neighborhood, denying them the ability to see me lipsync AC/DC with a tennis racket for a guitar.
1. Re:Didn't work for us in the late 1970s by operagost · 2016-03-01 08:40 · Score: 1
  
  You didn't have enough power. I mean, most of those RF modulators didn't even have external power sources, and were only designed to work through a few feet of coax.
  If you'd tried to hack one of those Rabbit cable TV/VCR signal extenders instead, it at least would have been designed to transmit over air and maybe you would have had enough power to do something.
  
  --
  
  Gamingmuseum.com: Give your 3D accelerator a rest.
2. Re:Didn't work for us in the late 1970s by Anonymous Coward · 2016-03-01 08:47 · Score: 0
  
  It'd probably have worked much better if you'd connected your RF modulator to the TV antenna using something called an amplifier.
3. Re:Didn't work for us in the late 1970s by serviscope_minor · 2016-03-01 08:51 · Score: 1
  
  Maybe the range was too far? I found I could use my 8 bitter to drive the TV across the room by connecting a TV antenna up to its RF out port. That was only a few meters though.
  
  --
  SJW n. One who posts facts.
4. Re:Didn't work for us in the late 1970s by Anonymous Coward · 2016-03-01 11:55 · Score: 1
  
  Here's the formula for easy NTSC broadcasting on Channel 3:
  1. NTSC device (VCR, camera, etc.) outputting via composite or S-Video and RCA R-L audio
  2. RF Modulator with output via RG-59 or RG-6 coax cable
  3. Channel Master or Winegard VHF-LO preamplifier with lots of gain
  4. Matching transformer ("balun") for converting 75 coax unbalanced to 300 twinlead balanced signal
  5. DIY dipole antenna with end-to-end width of 2.38095m (93.74in) and attachment points for balun leads
  6. connect device to modulator to preamp to matching transformer to dipole antenna
  7. profit!
Context by davidwr · 2016-03-01 07:31 · Score: 1

The term "radio transmission" is sometimes loosely used to mean "radio frequency transmission" which can mean over a coax or other wire carrying the signal rather than as photons through the air (or free space or water or what-not).
The Hack-a-day link specifically mentioned non-over-the-air applications using TV ("RF") frequencies.

--
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
Check out his youtube channel by bangular · 2016-03-01 07:41 · Score: 2

I stumbled across his youtube channel awhile back looking for info on etching pcbs. He has a few interesting projects going on. https://www.youtube.com/channe...
Now do it with ATSC by omnichad · 2016-03-01 07:42 · Score: 1

Right now, I think the cheapest ATSC "modulator" (probably not the right term) is in the neighborhood of $1000. Would be nice to connect something like this to in-home wiring to stream video over existing wiring.
1. Re:Now do it with ATSC by Anonymous Coward · 2016-03-01 11:59 · Score: 0
  
  The modulator is just one part of ATSC broadcasting. You would then need to feed the modulated signal into an ATSC exciter ($$$) and then to an antenna.
2. Re:Now do it with ATSC by rrp · 2016-03-01 12:18 · Score: 1
  
  There are some GNU Radio scripts that will let you broadcast ATSC with a Software Defined Radio (SDR), like the HackRF. Not sure how well they work, as I don't have a SDR, but I've been wanting to get one to try it out.
3. Re:Now do it with ATSC by Megane · 2016-03-02 00:01 · Score: 1
  
  You also would need a properly formatted MPEG stream before you even got a "modulated signal", which would add a second or two of delay if you started with analog or uncompressed video content. There are good reasons why an "ATSC modulator" is not a consumer product. One of them is the lack of reasons why NTSC modulators are a consumer product: ancient TV sets that had no other input. A TV set that can decode ATSC also has multiple other uncompressed video inputs, both analog and digital.
  An NTSC modulator is a passive device that converts a NTSC baseband signal to RF. An ATSC modulator would need to include an MPEG encoder or transcoder to generate the transport stream, as well as a sophisticated digital modulation technique, because nobody uses naked ATSC baseband signals for anything.
  
  --
  #naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
A wifi adapter allows you to jump an air gap? by Anonymous Coward · 2016-03-02 10:04 · Score: 0

You don't say?
Terrifying.