Hey great project Huan! I am into restoring or refinishing old antique radios and cabinets, and have implemented more than one "fake vintage" radio using a microcontroller - in the recent half-decade using SDR radio.
Over the years I had to implement a true random number generator on a microcontroller or small computer many times. My go-to circuit ever since my freshman year of college has used a germanium transistor plus an op-amp filter to provide the random seed. I have also the math overrun digits of a multiplication of two values sequenced from a small table of truly random numbers, though this worked better in older chipsets. More recently I have used the value from a RTC or values read from a GPS chip or NTP value as the seed value. But the pink noise generated by a germanium transistor has the fastest solution and is more evenly and flatter spread statistically than any other solution I have measured. And great for generating the signal required to create the sound signal for a parametric autotune of the filter path for a flat response to room acoustics, amp and speaker response, and microphone pickup of a sound system. - sgh On Mon, Jun 29, 2020 at 8:47 PM Huan Truong via TriEmbed < [email protected]> wrote: > Thanks, I sent it to the HAD staff via their "submit a hack" link on > their homepage and they are very kind. This is not the first time I've > done that and I really like the HAD staff. I hope it will wake up the > creativity of someone. In real life, this whole system looks actually > pretty attractive (and sounds nice, as I usually connect an external > amp to the faux radio whenever I don't feel nostalgic). > > https://youtu.be/QgBCnwq8A4g > > > > As a side note, getting random numbers out of a (deterministic) > computer is really hard. Getting nice, uniform numbers out of any > system is even harder, that's why cryptography is so hard. There is a > friend of mine, a significant and proud part of his work at Google is > to create a library that makes it easy to call cryptographic > functions. Specifically, part of it is to make it hard for programmers > to mess up/misuse the RNG. > > On Sun, Jun 28, 2020 at 7:41 AM Kevin McClaning via TriEmbed > <[email protected]> wrote: > > > > Excellent write up, Huan. > > > > Speaking of "silly" and "No one cares about," I once bought a scrolling > > LED sign at > > a ham fest but couldn't find documentation. I reverse-engineered the > > hardware so > > I could directly access the LED matrix with an Arduino, then set it > > about displaying > > humorous/motivational messages (of the kind you see at the bottom of > > slashdot), > > along with some random numbers and graphics. > > > > No, it doesn't stop there. I used the Arduino random number generator to > > select the individual > > messages to display but, I noticed that it always produced the same > > "random" order of messages. > > This annoyed me, so I added a temperature sensor and used its output to > > increase the entropy > > of the Arduino. Since I was in the "increase the entropy" neighborhood, > > I build two audio oscillators, > > with crappy stability and ran them into the AD converters of the > > Arduino. I sampled the waveforms > > every now and then and fed that into the Arduino's random seed as well. > > > > Yeah, "silly" but it was a fun diversion. Did all this in the > > before-the-pandemic timeframe. > > > > Kevin > > > > On 6/24/20 12:43 PM, Huan Truong via TriEmbed wrote: > > > This has taken me way more time than I thought, but finishing this > > > retrofit is a big achievement for me. It's really silly and serves > > > exactly no purpose other than RE'ing something no one cares about. So > > > I just want to share for some shits and giggles. > > > > > > > http://www.tnhh.net/posts/adventures-hacking-fake-vivitar-vintage-radio.html > > > > > > > > > > > > > > > > > > > > > _______________________________________________ > > Triangle, NC Embedded Computing mailing list > > > > To post message: [email protected] > > List info: > http://mail.triembed.org/mailman/listinfo/triembed_triembed.org > > TriEmbed web site: http://TriEmbed.org > > To unsubscribe, click link and send a blank message: mailto: > [email protected]?subject=unsubscribe > > > > > -- > > Huan Truong > www tnhh.net / twitter @huant > > _______________________________________________ > Triangle, NC Embedded Computing mailing list > > To post message: [email protected] > List info: http://mail.triembed.org/mailman/listinfo/triembed_triembed.org > TriEmbed web site: http://TriEmbed.org > To unsubscribe, click link and send a blank message: mailto: > [email protected]?subject=unsubscribe > > -- Scott G. Hall Raleigh, NC, USA [email protected] *Although kindness is rarely a job, no matter what you do it's always an option.*
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