On a sunny day (Tue, 19 Dec 2023 01:55:16 -0800 (PST)) it happened Lasse Langwadt Christensen <langwadt@fonz.dk> wrote in <0d59e35a-6272-49ea-aef6-51176f2b798dn@googlegroups.com>:>tirsdag den 19. december 2023 kl. 07.16.02 UTC+1 skrev Jan Panteltje: >> On a sunny day (Mon, 18 Dec 2023 16:40:42 -0800 (PST)) it happened Lasse >> Langwadt Christensen <lang...@fonz.dk> wrote in >> <50752cee-2eb8-4219...@googlegroups.com>: >> >mandag den 18. december 2023 kl. 19.24.58 UTC+1 skrev john larkin: >> >> https://www.dropbox.com/scl/fi/weo0og6siaf5ano8thng3/Opto_Shift_Reg.jpg?rlkey=g170fs3jzg6zftzrrvr3phmd4&raw=1 >> >> >> >> A short low pulse shifts a 1 and a long pulse shifts a 0. >> > >> >sorta similar to these LED drivers, https://www.tme.eu/dk/en/details/ws2811-m/led-drivers/worldsemi/ws2811-msop8/ >> Interesting, thanks you. > >it is the same or similar IC build into an RGB led that is in those cheap individually addressable LED strips > >https://www.aliexpress.com/item/4001322411818.htmlYea, if figured that, I have some normal LED strips here for Christmas with those individual addressable strips you could make interesting displays -but- I also have an old iconnect laser projector :-) Really cool thing :-) Connected to a Raspberry Pi. So I had not ordered those special LED strips.
opto shift register
Started by ●December 18, 2023
Reply by ●December 19, 20232023-12-19
Reply by ●December 19, 20232023-12-19
On Tue, 19 Dec 2023 06:04:01 GMT, Jan Panteltje <alien@comet.invalid> wrote:>On a sunny day (Mon, 18 Dec 2023 10:24:39 -0800) it happened john larkin ><jl@650pot.com> wrote in <re31oid9dqb1136cj5rctmnruvvhrm47nl@4ax.com>: > >>https://www.dropbox.com/scl/fi/weo0og6siaf5ano8thng3/Opto_Shift_Reg.jpg?rlkey=g170fs3jzg6zftzrrvr3phmd4&raw=1 >> >>A short low pulse shifts a 1 and a long pulse shifts a 0. > >What,s the use?One channel of an isolated temperature acquisition box. It will do RTDs, thermocouples, IC sensors, and cryo diodes. I need several isolated logic levels to switch ranges and such, and a multi-channel logic isolator is big and expensive. I don't need speed. The alternative is to use a bunch of single-lane SSRs. Or maybe float a uP per channel and talk to it with one bidirectional isolator. Early stages of design, many possibilities.
Reply by ●December 19, 20232023-12-19
tirsdag den 19. december 2023 kl. 16.32.07 UTC+1 skrev John Larkin:> On Tue, 19 Dec 2023 06:04:01 GMT, Jan Panteltje <al...@comet.invalid> > wrote: > >On a sunny day (Mon, 18 Dec 2023 10:24:39 -0800) it happened john larkin > ><j...@650pot.com> wrote in <re31oid9dqb1136cj...@4ax.com>: > > > >>https://www.dropbox.com/scl/fi/weo0og6siaf5ano8thng3/Opto_Shift_Reg.jpg?rlkey=g170fs3jzg6zftzrrvr3phmd4&raw=1 > >> > >>A short low pulse shifts a 1 and a long pulse shifts a 0. > > > >What,s the use? > One channel of an isolated temperature acquisition box. It will do > RTDs, thermocouples, IC sensors, and cryo diodes. I need several > isolated logic levels to switch ranges and such, and a multi-channel > logic isolator is big and expensive. I don't need speed.there's also, SN74LV8153, uart to 8 bit> The alternative is to use a bunch of single-lane SSRs. > > Or maybe float a uP per channel and talk to it with one bidirectional > isolator.it needs programming but makes a whole lot of other things easy
Reply by ●December 19, 20232023-12-19
On Tue, 19 Dec 2023 09:09:28 -0800 (PST), Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:>tirsdag den 19. december 2023 kl. 16.32.07 UTC+1 skrev John Larkin: >> On Tue, 19 Dec 2023 06:04:01 GMT, Jan Panteltje <al...@comet.invalid> >> wrote: >> >On a sunny day (Mon, 18 Dec 2023 10:24:39 -0800) it happened john larkin >> ><j...@650pot.com> wrote in <re31oid9dqb1136cj...@4ax.com>: >> > >> >>https://www.dropbox.com/scl/fi/weo0og6siaf5ano8thng3/Opto_Shift_Reg.jpg?rlkey=g170fs3jzg6zftzrrvr3phmd4&raw=1 >> >> >> >>A short low pulse shifts a 1 and a long pulse shifts a 0. >> > >> >What,s the use? >> One channel of an isolated temperature acquisition box. It will do >> RTDs, thermocouples, IC sensors, and cryo diodes. I need several >> isolated logic levels to switch ranges and such, and a multi-channel >> logic isolator is big and expensive. I don't need speed. > >there's also, SN74LV8153, uart to 8 bit >That's slick. Might work. It would need a single-channel isolator, which isn't bad.
Reply by ●December 20, 20232023-12-20
On a sunny day (Tue, 19 Dec 2023 07:31:03 -0800) it happened John Larkin <jl@997PotHill.com> wrote in <r9d3oipchi8i1no29gu1rlccg0mlnn3llc@4ax.com>:>On Tue, 19 Dec 2023 06:04:01 GMT, Jan Panteltje <alien@comet.invalid> >wrote: > >>On a sunny day (Mon, 18 Dec 2023 10:24:39 -0800) it happened john larkin >><jl@650pot.com> wrote in <re31oid9dqb1136cj5rctmnruvvhrm47nl@4ax.com>: >> >>>https://www.dropbox.com/scl/fi/weo0og6siaf5ano8thng3/Opto_Shift_Reg.jpg?rlkey=g170fs3jzg6zftzrrvr3phmd4&raw=1 >>> >>>A short low pulse shifts a 1 and a long pulse shifts a 0. >> >>What,s the use? > >One channel of an isolated temperature acquisition box. It will do >RTDs, thermocouples, IC sensors, and cryo diodes. I need several >isolated logic levels to switch ranges and such, and a multi-channel >logic isolator is big and expensive. I don't need speed. > >The alternative is to use a bunch of single-lane SSRs. > >Or maybe float a uP per channel and talk to it with one bidirectional >isolator. > >Early stages of design, many possibilities.For that, if I understand your description right, I usually grab a Microchip PIC micro. It has many outputs that can drive optocouplers, both for in - and outputs. Then it can do Ethernet to a main computer too with one extra chip. I am a bit worried about the timing capacitors in your idea, caps may drift over time and temperature?
Reply by ●December 20, 20232023-12-20
On a sunny day (Tue, 19 Dec 2023 11:28:26 GMT) it happened Jan Panteltje <alien@comet.invalid> wrote in <ulruor$29dr$1@solani.org>:>On a sunny day (Tue, 19 Dec 2023 01:55:16 -0800 (PST)) it happened Lasse >Langwadt Christensen <langwadt@fonz.dk> wrote in ><0d59e35a-6272-49ea-aef6-51176f2b798dn@googlegroups.com>: > >>tirsdag den 19. december 2023 kl. 07.16.02 UTC+1 skrev Jan Panteltje: >>> On a sunny day (Mon, 18 Dec 2023 16:40:42 -0800 (PST)) it happened Lasse >>> Langwadt Christensen <lang...@fonz.dk> wrote in >>> <50752cee-2eb8-4219...@googlegroups.com>: >>> >mandag den 18. december 2023 kl. 19.24.58 UTC+1 skrev john larkin: >>> >> https://www.dropbox.com/scl/fi/weo0og6siaf5ano8thng3/Opto_Shift_Reg.jpg?rlkey=g170fs3jzg6zftzrrvr3phmd4&raw=1 >>> >> >>> >> A short low pulse shifts a 1 and a long pulse shifts a 0. >>> > >>> >sorta similar to these LED drivers, https://www.tme.eu/dk/en/details/ws2811-m/led-drivers/worldsemi/ws2811-msop8/ >>> Interesting, thanks you. >> >>it is the same or similar IC build into an RGB led that is in those cheap individually addressable LED strips >> >>https://www.aliexpress.com/item/4001322411818.html > >Yea, if figured that, I have some normal LED strips here for Christmas >with those individual addressable strips you could make interesting displays >-but- I also have an old iconnect laser projector :-) >Really cool thing :-) Connected to a Raspberry Pi. >So I had not ordered those special LED strips.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.html Then 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
Reply by ●December 20, 20232023-12-20
On 20/12/2023 2:31 am, John Larkin wrote:> On Tue, 19 Dec 2023 06:04:01 GMT, Jan Panteltje <alien@comet.invalid> > wrote: > >> On a sunny day (Mon, 18 Dec 2023 10:24:39 -0800) it happened john larkin >> <jl@650pot.com> wrote in <re31oid9dqb1136cj5rctmnruvvhrm47nl@4ax.com>: >> >>> https://www.dropbox.com/scl/fi/weo0og6siaf5ano8thng3/Opto_Shift_Reg.jpg?rlkey=g170fs3jzg6zftzrrvr3phmd4&raw=1 >>> >>> A short low pulse shifts a 1 and a long pulse shifts a 0. >> >> What,s the use? > > One channel of an isolated temperature acquisition box. It will do > RTDs, thermocouples, IC sensors, and cryo diodes. I need several > isolated logic levels to switch ranges and such, and a multi-channel > logic isolator is big and expensive. I don't need speed. > > The alternative is to use a bunch of single-lane SSRs. > > Or maybe float a uP per channel and talk to it with one bidirectional > isolator. > > Early stages of design, many possibilities.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 75MHz serial link but AMD upgraded it to 125 MHz. 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. -- Bill Sloman, Sydney>
Reply by ●December 20, 20232023-12-20
On Wed, 20 Dec 2023 05:18:42 GMT, Jan Panteltje <alien@comet.invalid> wrote:>On a sunny day (Tue, 19 Dec 2023 07:31:03 -0800) it happened John Larkin ><jl@997PotHill.com> wrote in <r9d3oipchi8i1no29gu1rlccg0mlnn3llc@4ax.com>: > >>On Tue, 19 Dec 2023 06:04:01 GMT, Jan Panteltje <alien@comet.invalid> >>wrote: >> >>>On a sunny day (Mon, 18 Dec 2023 10:24:39 -0800) it happened john larkin >>><jl@650pot.com> wrote in <re31oid9dqb1136cj5rctmnruvvhrm47nl@4ax.com>: >>> >>>>https://www.dropbox.com/scl/fi/weo0og6siaf5ano8thng3/Opto_Shift_Reg.jpg?rlkey=g170fs3jzg6zftzrrvr3phmd4&raw=1 >>>> >>>>A short low pulse shifts a 1 and a long pulse shifts a 0. >>> >>>What,s the use? >> >>One channel of an isolated temperature acquisition box. It will do >>RTDs, thermocouples, IC sensors, and cryo diodes. I need several >>isolated logic levels to switch ranges and such, and a multi-channel >>logic isolator is big and expensive. I don't need speed. >> >>The alternative is to use a bunch of single-lane SSRs. >> >>Or maybe float a uP per channel and talk to it with one bidirectional >>isolator. >> >>Early stages of design, many possibilities. > >For that, if I understand your description right, >I usually grab a Microchip PIC micro. > >It has many outputs that can drive optocouplers, >both for in - and outputs. >Then it can do Ethernet to a main computer too with one extra chip. >I am a bit worried about the timing capacitors in your idea, >caps may drift over time and temperature?I plan to use one RP2040 in the box, as the top level manager. The question is then how to talk to four isolated temprature measurement channels. People sometimes weld thermocouples to whatever, or bolt raw cryo diodes to metal things, so I need true isolation. A uP per channel is probably overkill. I've done that before but it's a nuisance. If I do the long/short pulse thing, the pulse width ratio can be 10:1 or 100:1 so capacitor tolerance wouldn't matter.
Reply by ●December 20, 20232023-12-20
On a sunny day (Wed, 20 Dec 2023 04:20:54 -0800) it happened John Larkin <jl@997PotHill.com> wrote in <lim5oi5afhvee38tb5can9id36k1bgcic9@4ax.com>:>On Wed, 20 Dec 2023 05:18:42 GMT, Jan Panteltje <alien@comet.invalid> >wrote: > >>On a sunny day (Tue, 19 Dec 2023 07:31:03 -0800) it happened John Larkin >><jl@997PotHill.com> wrote in <r9d3oipchi8i1no29gu1rlccg0mlnn3llc@4ax.com>: >> >>>On Tue, 19 Dec 2023 06:04:01 GMT, Jan Panteltje <alien@comet.invalid> >>>wrote: >>> >>>>On a sunny day (Mon, 18 Dec 2023 10:24:39 -0800) it happened john larkin >>>><jl@650pot.com> wrote in <re31oid9dqb1136cj5rctmnruvvhrm47nl@4ax.com>: >>>> >>>>>https://www.dropbox.com/scl/fi/weo0og6siaf5ano8thng3/Opto_Shift_Reg.jpg?rlkey=g170fs3jzg6zftzrrvr3phmd4&raw=1 >>>>> >>>>>A short low pulse shifts a 1 and a long pulse shifts a 0. >>>> >>>>What,s the use? >>> >>>One channel of an isolated temperature acquisition box. It will do >>>RTDs, thermocouples, IC sensors, and cryo diodes. I need several >>>isolated logic levels to switch ranges and such, and a multi-channel >>>logic isolator is big and expensive. I don't need speed. >>> >>>The alternative is to use a bunch of single-lane SSRs. >>> >>>Or maybe float a uP per channel and talk to it with one bidirectional >>>isolator. >>> >>>Early stages of design, many possibilities. >> >>For that, if I understand your description right, >>I usually grab a Microchip PIC micro. >> >>It has many outputs that can drive optocouplers, >>both for in - and outputs. >>Then it can do Ethernet to a main computer too with one extra chip. >>I am a bit worried about the timing capacitors in your idea, >>caps may drift over time and temperature? > >I plan to use one RP2040 in the box, as the top level manager. The >question is then how to talk to four isolated temprature measurement >channels. People sometimes weld thermocouples to whatever, or bolt raw >cryo diodes to metal things, so I need true isolation. > >A uP per channel is probably overkill. I've done that before but it's >a nuisance.Well the thing will have to understand commands, and sent data.. or is it just one-way traffic? sensor to raspberry? Using logic takes more chips than a micro.>If I do the long/short pulse thing, the pulse width ratio can be 10:1 >or 100:1 so capacitor tolerance wouldn't matter.Looks like a simple serial protocol like for example used via PC serial port would be OK. 2 photo couplers per channel, one for each direction, You need supply insulation too, so one potcore at RF with a few flat cable thick windings, one for each sensor unit https://www.panteltje.online/pub/1_to_1_transformer_in_1_minute.jpg 1 transistor sine wave oscillator to power all units: https://www.panteltje.online/pub/tuned_eprom_programmer_voltage_generator.gif Raspi can mimic several serial ports via the GPIO pins. Depends a bit how many task interups happen via the software. On the Pi4 there seem to be 4 hardware serial ports? https://forums.raspberrypi.com/viewtopic.php?t=244528 I only ever used ttyAMA0 (GPS module connected to it). # ls /dev/ttyAMA* /dev/ttyAMA0
Reply by ●December 20, 20232023-12-20
On Monday, December 18, 2023 at 1:24:58 PM UTC-5, john larkin wrote:> https://www.dropbox.com/scl/fi/weo0og6siaf5ano8thng3/Opto_Shift_Reg.jpg?rlkey=g170fs3jzg6zftzrrvr3phmd4&raw=1 > > A short low pulse shifts a 1 and a long pulse shifts a 0.You can't beat that for simplicity and reliability. The first bit always has to be a 0, and you probably want to blank the output whenever you put the register into a new state.
