#2103

[@donmcclincy2371]

The FT is Feed Through, which is what it's doing. Try switching FT off and recording.

[@lifegettingintheway2710]

You made an assumption about a feature and followed it down a rabbit hole. It stopped being predictable when you tested your assumption (you moved the feed-thru switch) but never put it back before continuing your test. I tried to get your attention by yelling but only my wife heard me :)

[@johnwest7993]

He'll figure it out, whether he looks at the comments or not. He's like me. It will bug him when something doesn't work, especially something simple. Give him a couple of hours and he'll be drawn back to it, and without the video recorder running he'll figure it out in under a minute. If he's like me he can't talk and troubleshoot at the same time.

[@rfburns5601]

I remember when Radio Shack was selling these and 73 magazine came with a simplex repeater. A friend and I built one. Using a simplex repeater requires extreme conversation discipline that most people (including myself) don't have. But it is amazing the receive sensitivity that can be gained by not having a transmitter operating 600 kc away. Not to mention the cost reduction of unneeded duplexers.

[@retireeelectronics2649]

The ISC1820 module is great for adding sound to Halloween etc displays and dirt cheap.

[@robinbrowne5419]

My friend received a birthday card from his sister and we could hear them singing happy birthday and giggling away.

[@tommiller1315]

The COB version is about $1, while the PCB with speaker & mic can be found for $1.47, both from China! (Free post too, if you can find it).

[@ScottHenion]

Had a client that used one of those ISD chips in a drive-thru kiosk to play canned messages. All those N/C pins are for start addresses to rec/play multiple messages on the larger chips. They are a bit weird in their interface. The client had it working in a mode it was not designed. Interesting there is no A/D or D/A, the audio is stored in an analog format in flash memory.

[@humidbeing]

It has to be quantized to store in digital flash memory.

[@ScottHenion]

@@humidbeing It is not digital memory. It is analog. The flash cells are programmed with a charge proportional to the voltage.

[@rfburns5601]

@@humidbeing Actually, no. Each memory cell is not a bit - or binary digit - each cell stores an analog value like a CCD image sensor in a camera. Later, the CCD output is digitally processed, but the ccd imaging sensor is analog. The olden name for these were bucket brigade devices like the 1970s SAD 1024? by Panasonic that was used in many guitar effects pedals. It is digitally controlled analog memory.

[@nevellgreenough404]

These boards make fantastic CQ callers for older ham radio rigs! I've made several. Great for contests. --N2GX

[@stevenhughes1254]

FT switch man you turned feed through on

[@_MisterG]

Two videos of the same chip today :) Then I went down a rabbit hole for effects devices for simple synthesizers etc Thank you

[@user.A9]

Everybody loves chip of the day!

[@mikeonthebox]

It was probably commented already, but I believe you needed to hold down the REC button for it to record. (I think)

[@timwoodland3664]

Hold the record button down while recording. Record: The REC input is an active-HIGH record signal. The device records whenever REC is HIGH. This pin must remain HIGH for the duration of the recording.

[@mikeonthebox]

I was just commenting the same. Yes this confirms what I though. Lets hope he see the comments.

[@frankowalker4662]

I bought 3 very similar PCB's with blob chips on. They are really small and mega cheap. But they work really well.

[@herbertsusmann986]

I have some old ones of these back when ISD was its own company. I think I got mine back in the 90's some time. Someone must have bought out that company and is still making the chips. The old ones were based on analog EEPROM cells where it would store an analog charge on the memory cell and then read it out in an analog fashion. Kind of a lost technology these days.

[@bendunselman]

I have one of those laying around for a long time waiting for an application.

[@DimasFajar-ns4vb]

wow and peace be upon you sir from me

[@bendunselman]

RTFM again

[@ebenwaterman5858]

I'd like to see more on this chip. Specifically the clock. Can the playback speed be modulated with the clk. Thanx for discovering this tech. I had no idea this existed. :)

[@sefarkas0]

Datasheet is 24pin module is 14, can't find data sheet, not even on mfgr site.

[@ats89117]

This is a good example of a write only memory...

[@analog_guy]

The Signetics 25120 Write Only Memory would make a good "chip of the day". I see that "uniservo" has a video featuring it, including an actual example.

[@humidbeing]

It's doing exactly what you told it to do. Another RTFM fail video.

[@jyvben1520]

Jan 8 2025 :: video at 3:29 shows datasheet is from Jan 15 2016,, website's newer version Feb 1 2023 has no alternate circuit ...

[@jj74qformerlyjailbreak3]

I have the Dip IC version of these boards. I can send you some spares.

[@jsdutky]

remove the chip, and build the example circuit!

[@robinbrowne5419]

Awww.. disappointing. Please get this working and record the message. 👍

[@mr1enrollment]

the proper term is 'kludge' ;-]