opto shift register

The idea has been used in an Electronics Design Idea: an even longer pulse was used to gate the output latch. It was used to drive an LCD display (HD44780) using one line only.

Arie

Well,that's cute, but not useful without some guaranteed resting high time for the pulse train. If the cap doesn't recharge fully between low intervals, it gets indeterminate as to what happens.

Sure, but I'll control the drive waveform.

I want a bunch of pretty slow isolated control signals, and multi-channel digital isolators are big and expensive.

That's slick. Might work. It would need a single-channel isolator, which isn't bad.

On a sunny day (Tue, 19 Dec 2023 11:28:26 GMT) it happened Jan Panteltje snipped-for-privacy@comet.invalid wrote in <ulruor$29dr$ snipped-for-privacy@solani.org:

PS, as it is the time of year, I have some RGB LED strips, and wrote some stuff so it displays colors when you play music so one could play Christmas like songs Basically an audio equalizer, spectrum filter: http://panteltje.online/panteltje/xpequ/index.html drives a simple RGB strip, red for low frequencies, green for middle, blue for high ones, via RS232: https://panteltje.online/panteltje/pic/col_pic/index.htmlThen I later added an Ethernet RGB LED driver: https://panteltje.online/panteltje/pic/ethernet_color_pic/index.html now in use all the time.

Script to make it play some mp3 file via the RGB LED strips: mpg123 -w - music.mp3 | xpequ -i - -t /dev/dsp0 -q 192.168.178.157 -j 102

This is even older: https://panteltje.online/panteltje/pic/sign_pic/ And then again in RGB mounted on a drone: https://panteltje.online/panteltje/quadcopter/hsign.html

Send long enough words and one isolated serial link would do the job. Back in 1988 we used AMD's Taxichips to send 16-bit words, and you could string more of them together to send longer words. We started off with a

That's too fast for opto-isolators (or was then) and we used 1:1 isolating transformers wound with twisted pair - not a lot of voltage stand-off, but we didn't need that. I wound the first one with minature coax, which worked fine (and would have stood off a lot more volts) but it would have been more expensive. The bifilar wound isolators are off-the shelf parts now.

Dallas one wire interface? I recall some Manchester chips that could do that. Ran some hp optical interfaces, worked ok.

Cheers

It will take more than a minute to mount and connect that on a PCB.

A stock tiny surface-mount isolated dc/dc converter costs about $2.

I could bit-bang it too. But I'll use the Pico processor, the RP2040 chip. The Pi4 is about as big as my entire product!

One might use Ethernet magnetics, two transformers, as a logic isolator too. Clock and data.

For once. Your rant is actually Anthony Watts' rant, and climate change denial propaganda, but you don't know enough to realise quite how silly Anthony Watts' obsessions are.

I have here a 200 led Christmas ornament. 20 m with leds separated at 10 cm.

The output is two leads, but there is button that can switch

- continuous all

- odd even alternating with odd flashing and even flashing

- od even flashing alternating with gradually dimming and increasing

- all off

- continuous even

- continuous odd

- erratically flashing.

I wonder how they do it. There is probably a ucontroller in the tiny box. It rattles as you shake it.

Groetjes Albert