hybridfree/eevblog-posts huggingface dataset:
Slide switch caps - Page 1
Forum section: electronics / projects

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 22, 2020, 11:02:38 am
content: Anyone ran across something like this?Would be nice to have a cap for a switch like this:https://www.digikey.com/product-detail/en/nidec-copal-electronics/CL-SB-12B-02T/563-1319-1-ND/3507886It doesn't have anything to snap to, but could be glued in, or confined by a panel.I have an application where one of these switches is mounted on a PCB, which is mounted to the bosses in a molded enclosure (the usual Hammond, etc. ABS boxes). The heights of these bosses, and thickness of the face, seem somewhat de facto standard, so it's not a huge stretch to wonder if something fits...Shape would be, imagine a flat plate that has been embossed. This makes a cavity on one side, in which the switch's slider rests. The top face rests against the inside of the enclosure, trapping it against the switch. The bottom face either rests against the switch body, or clears it. The emboss sticking out of the top face gets extended, maybe textured on top or something, to push by the user.Have seen these in commercial products many times but haven't run across one in a catalog, and it occurs to me they're bound to be just about impossible to search for..Tim

author: bin_liu
author_rank: Contributor
timestamp: June 23, 2020, 01:27:46 am
content: The cap of this switch has a very big relationship with the product shell. In China, I have not seen any public models that can be purchased and used. It is recommended that you 3D print or use another model of switch.
Slide Switch Terminology - Page 1
Forum section: electronics / projects

author: ElectronicTonic
author_rank: Contributor
timestamp: December 04, 2013, 04:58:26 pm
content: In the schematic in Dave's recent uCurrent video (#552), I saw the switches labeled as "SW-DT3T-NOCOMMON".What does the "DT3T" stand for?I am certainly familiar with "Pole" and "Throw" terms, like "DP3T" for switches that have a common terminal, but what is the proper way to describe a slide switch with a contact moving from one pair of terminals to a second pair and to a third pair with no common terminal?Another example is this switch specified as "Double Pole, Three Position"http://switches-connectors-custom.cwind.com/item/standard-slide-switches-2/top-actuated-maintained-slide-switches-2/g-328s-0000Just as in Dave's schematic, it has 4 evenly spaced terminals on each side with a sliding contact that connects two at a time, like this old-school html-ish diagram:| | | |O O O O# #. . . # # . . .#========##========#. . . # # . . .# #O O O O| | | |I am also familiar with other slide switches with 3 positions in which the terminals are not evenly spaced and are arranged in such a way that they do indeed have a common terminal. My question is, what is the best way to describe a slide switch that has 4 or 5 evenly spaced terminals per side (3 position or 4 position, respectively) with no common terminal?

author: AndersAnd
author_rank: Frequent Contributor
timestamp: December 04, 2013, 06:45:07 pm
content: Quote from: ElectronicTonic on December 04, 2013, 04:58:26 pmNot sure what the proper term to describe these are (if there is any term), but C&K still calls it DP3T even though there's no common terminal for all 3 throws.Some examples are C&K OS203013MT6QN1 and OS203013MT8QN1.C&K OS series datasheet:http://www.ck-components.com/14388/os_11mar13.pdf/
Sliding DFT with an IQ stream - Page 1
Forum section: electronics / projects

author: Harvs
author_rank: Super Contributor
timestamp: October 07, 2024, 09:36:56 pm
content: I'm looking at using a sliding DFT for demodulating a FSK signal on a uC. The Real input single bin DFT is simple and there's loads of examples on the net. But I have a hardware system that already has both the I & Q available from RF down-conversion that I'd like to use.Has anyone seen an explanation of the Sliding DFT or similar for a quadrature signal? It feels like it shouldn't be terribly difficult, but google is returning blank.

author: moffy
author_rank: Super Contributor
timestamp: October 07, 2024, 11:31:58 pm
content: Not sure if it's helpfull but the following article has an analysis of the DFT with respect to IQ signals:http://www.hyperdynelabs.com/dspdude/papers/quadrature%20signal%20processing.pdf

author: Nominal Animal
author_rank: Super Contributor
timestamp: October 08, 2024, 12:47:04 am
content: You do complex DFT, with I being the real part, and Q the imaginary part.Unlike in the real-input DFT, this time the frequency domain does not have a conjugate, and you want to look at allNbins (instead ofN/2 bins, as you do with real input).Because you have twice the data compared to plain real inputs, you get twice the results, and the calculation takes more MCU/CPU time.

author: jbb
author_rank: Super Contributor
timestamp: October 08, 2024, 02:56:19 am
content: You could also consider a Phase Locked Loop (PLL) based detector for FSK demodulation…

author: Harvs
author_rank: Super Contributor
timestamp: October 08, 2024, 09:48:10 am
content: Thanks, after reading those links and pondering Nominal Animal's response it sunk in that all it was is the same DFT equation with the complex stream as an input.That's all quite straightforward to process, only adds another couple of multiplies to get the full Fs bandwidth.
Sliding microscope mount - Page 1
Forum section: electronics / projects

author: Zbig
author_rank: Frequent Contributor
timestamp: October 08, 2020, 07:53:46 pm
content: Not happy with the standard manufacturer-provided stand for my digital microscope and its lack of flexibility, I have built my own solution - under-shelf, over-the-bench X-Y slider:It mostly uses ready-made aluminium extrusions, plates, rollers and other elementsfound here, and some custom 3d-printed parts, mostly related to the belt-synchronised, two-stage Y-axis movement mechanism.

author: Dubbie
author_rank: Unknown
timestamp: October 08, 2020, 08:04:02 pm
content: Nice!

author: moffy
author_rank: Super Contributor
timestamp: October 11, 2020, 03:47:40 am
content: I'll go one better: Very Nice!But the workspace is so neat!

author: negativ3
author_rank: Regular Contributor
timestamp: October 11, 2020, 04:56:24 am
content: That's nice enough for you to share the build files with us?

author: Zbig
author_rank: Frequent Contributor
timestamp: October 11, 2020, 06:27:24 pm
content: Thank you, guys. Regarding the build files, well the "core" is constructed fromhttps://openbuilds.comparts and I just kind of winged it so there's no formal documentation for that as such but feel free to ask in case you have questions.Regarding my custom 3D printed parts (dealing with the belt mechanics mostly), I've put the STL files here if you're interested:https://git.tristated.io/zbig/microscope_sliderIf you're an Autodesk Fusion 360 user and would rather have the cloud access to the project (instead of just the resulting STLs), shoot me a DM with your email address and I'll invite you.

author: cdev
author_rank: Super Contributor
timestamp: October 11, 2020, 10:11:46 pm
content: Thats just beautiful.Everything is so color-coordinated. It doesnt look like my desk at all. Not even remotely.It must make it almost effortless to work compared to my ordeal of first finding all the stuff I need in my clutter.Quote from: Zbig on October 08, 2020, 07:53:46 pm

author: negativ3
author_rank: Regular Contributor
timestamp: October 12, 2020, 06:10:04 am
content: Looks like 30x90 T-nut profile?

author: Zbig
author_rank: Frequent Contributor
timestamp: October 12, 2020, 08:18:23 am
content: Quote from: negativ3 on October 12, 2020, 06:10:04 amThe X axis (along the shelf’s length) is 20x80 (2 pieces 500 mm long each) and the Y segments are 20x60 (250 mm in length/ea).
Sliding rack mount - Page 1
Forum section: electronics / projects

author: tkamiya
author_rank: Super Contributor
timestamp: November 12, 2020, 05:50:38 am
content: I am in process of making something using a discarded HP8568 case. For all practical purposes, you can imagine it's just a lightened version of the bottom half of HP8568. (RF section)I need to mount it to rack but it will have to slide all the way out and allow me to open the top cover. As you know, HP cases of this vintage are only secured with one screw at the very end. That screw will remain lose. I want to just slide it out, change configurations, and slide it back in. All without discounting the whole thing from rack.I've seen this kind of setup on rack mount computer servers, but has anyone seen it done on HP cabinet? The rack itself will be secured so it won't topple over, by the way. The total weight will likely be 20Kg or less.

author: Berni
author_rank: Super Contributor
timestamp: November 12, 2020, 09:18:13 am
content: Yep i do have some equipment installed on sliding rails in a rack. But i use the sliding rails mostly because i'm just reusing the accessories that came with the old rack i bought used locally (The servers got taken out but all the cables, mounting hardware and shelves got left behind inside it).The problem is that these sliding rails use a different attachment method. They need the thing they hold to have a series of threaded holes down both sides so that you can screw the rails onto it. Not all test gear has those holes. Perhaps if you remove the handles, the handle holes can line up with some holes on the slide rail.There are some rails that also feature a L profile along them so that it grabs the bottom corners of the case, but still need some screws to properly hold it (It just makes installation easier). But a universal solution for everything is to just mount a rackmount shelf onto the sliding rails to give you a sliding shelf. You might need to drill the holes down the sides yourself but once you got one any piece of equipment can be placed on it.Or perhaps you can find a ready made sliding shelf that is beefy enough to hold full sized gear. The rack mount sliding shelves you usually see are meant for holding keyboards and similar, perhaps someone makes a big full depth version of those.

author: drussell
author_rank: Super Contributor
timestamp: November 12, 2020, 09:33:56 am
content: Quote from: Berni on November 12, 2020, 09:18:13 amHeavy-duty equipment-sized rack-mount sliding shelves are readily available.eg:https://www.rackmountsolutions.net/sliding-rack-mount-shelves/This one is even rated to handle up to 200 lbs:https://www.middleatlantic.com/products/accessories/adjustable-sliding-rackshelves/sliding-shelf/sshd-28.aspxI've also made my own sliding rail systems before using a bunch of surplus heavy duty ball bearing slides I got from Princess Auto for $9.99 or $14.99ea or something... I think I still have a few around somewhere that I didn't end up using yet.
Slim ceiling downlights - Page 1
Forum section: electronics / projects

author: akis
author_rank: Frequent Contributor
timestamp: July 02, 2020, 06:02:46 pm
content: hello, has anyone got experience with (very) slim ceiling downlights to use in bathroom and kitchen? I would like to avoid joists and noggins if at all possible. My ceilings are about 24mm thickness, so any lights that will fit in that space or less? How do these compare to the ordinary halogen/LED downlights?

author: fordem
author_rank: Regular Contributor
timestamp: July 25, 2020, 01:07:17 am
content: I have some chinese made RCA branded LED downlights in my bathroom - only 10mm thick - they can be installed in a 24mm thick ceiling, provided there is space above the ceiling to take the wiring & LED driver, which is about a 50mm x 25mm x 25mm cube on a short fly lead.The image below gives you an idea of what it looks like and also how it is secured - cut a circular hole, large enough to pass the body of the light, but smaller than the flange, fold the spring latches back and slip the lamp into the hole and push it until the flange seats against the ceiling - the latches will spring back and sit against the ceiling, securing the lamp in place.Your concern about avoiding joists & noggins is unclear to me - these lamps are light enough that they do not need to be affixed to a joist or noggin, they can be fitted to suspended ceiling tiles with no additional support - if there is a joist or noggin where you wish to mount the lamp once there is sufficient space for the wiring and the mounting clips to clear the joist - maybe rotate the lamp so they are at right angles to the joist - you should have no trouble.I have half a dozen of these installed and in a two year period I have had one LED driver fail.
Slo-blo fuse - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 12, 2020, 05:41:57 am
content: I'm repairing my Dad's 1959 Grundig cabinet radio. The fuse is still good but I can't figure out what type it is. It must be a slo-blo of some kind to allow the filaments to heat up I guess, but I've never seen a 5mm x 20mm 1 amp fuse built with two tension springs.I usually see that kind of arrangement in higher current ratings.Would a modern slo-blo fuse work as well? I'm asking because I recently found out there are no more electronics stores near me or my Dad's place that sell fuses anymore, so I have to use my limited stock of 5x20 fuses.I can see the fast acting type just has a hair-thin filament, and the slo-blo variant has a blob of solder or something on the filament.Are there different ratings of slo-blo, like even slower for tubes?

author: bob91343
author_rank: Super Contributor
timestamp: November 12, 2020, 10:16:19 pm
content: What are the markings on the end caps of the fuse? There are variations in slow blow fuses so you have to know the details to get the proper part.

author: Vovk_Z
author_rank: Super Contributor
timestamp: November 13, 2020, 02:45:16 pm
content: I'm 95% sure it can be replaced with any actual 1A slow-blow fuse.The spring there can be for some technological purposes in the 1970s.

author: bob91343
author_rank: Super Contributor
timestamp: November 13, 2020, 07:12:57 pm
content: I believe the 'spring' is actually a calibrated heat buffer to control the speed of temperature rise.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 13, 2020, 07:15:32 pm
content: It's also possible it's not a 1A fuse, just something someone slapped in there once.The terminals are corroded and the fuse markings are not legible because of the corrosion, probably from watering the plant that my Mom left on the cabinet..

author: ejeffrey
author_rank: Super Contributor
timestamp: November 13, 2020, 07:18:34 pm
content: Just measure the current and the inrush duration with a meter and pick an appropriate fuse?

author: bob91343
author_rank: Super Contributor
timestamp: November 14, 2020, 05:31:35 am
content: Look up the model and Google it to find the diagram, which should give the info you want.

author: james_s
author_rank: Super Contributor
timestamp: November 14, 2020, 06:27:05 am
content: I've seen slow blow fuses that had a spring in them sort of like that, the ones I had used a soldered joint inside and when the element heats up enough to melt the solder the spring would pull it apart. It probably isn't critical though, fuses are not precision devices.
Slope detection circuit or Edge detection circuit proposal - Page 1
Forum section: electronics / projects

author: zero0d
author_rank: Contributor
timestamp: March 15, 2022, 02:33:34 pm
content: Hi All,i need some help to put me in to right detection and to choose the right circuit for slope or rising edge detection circuit using OPAMP or Comparator or something elseHere is my block diagram in attachment:1) i have a hall current sensor eg from Infineon PN: TLI4971-A025T5-E0001.I'm applying current pulses to the hall sensor:-> The current can be from 100mA to 10A ( the hall sensor will produce voltage with 1us delay at the output from 0V to 5V depending on the current)-> The current pulses can have ton_min= 10us , ton_typ = 100us, and a typical frequency of 100Hz to 1kHz2) on the other hand i have a mcu of FPGA digital input, when goes from low to high ( means current is pressent), when goes from high to low ( current not present, but this transition is not critical)Primarily i want to detect the current is present.3) So I'm looking for a circuit that can detect the rising slope and give a high(3.3V or 5V) to the MCU for the given range of currents (100mA to 10A)I was thing about a non-inverting differentiator or a input AC coupled non inverting OPAMP with high gain and high speed GBW, but i can't find much data on those approaches.Thank you and Br.

author: Terry Bites
author_rank: Super Contributor
timestamp: March 15, 2022, 03:17:35 pm
content: Something like this? Adjust R2 for threshold.

author: zero0d
author_rank: Contributor
timestamp: March 16, 2022, 07:10:54 am
content: Hi Terry,i tried the simulation in TINA-TI, but i didn't get a behavior that i want. (Attached, need to run Analysis Transient)One thing i noticed in your picture is that you didn't use square signal on the input, why? the signal from Hall sensor is square ( in my sim i used 480mV amplitude that represents 10A current)

author: zero0d
author_rank: Contributor
timestamp: March 16, 2022, 07:17:48 am
content: Ok, i now got it to work , need to change the threshold very low-> I set the R1( your R2) to 1k.Also i have to check if it will work with 5mV input.It now works, but it is inverted.
Slots in PCBs - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: November 05, 2020, 04:30:24 pm
content: I would like some rectangular slots in my PCBs.... but I presume in reality it would be impossible to make them exactly square since the router bit must have some finite width??How should I specify them ? As rectangles or with mitred corners?

author: ejeffrey
author_rank: Super Contributor
timestamp: November 05, 2020, 04:35:03 pm
content: Normally a slot will be made with a single pass of a mill with the appropriate diameter and have rounded ends. Cutouts wider than a single tool pass would have rounded corners.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: November 05, 2020, 04:36:39 pm
content: So the router would cut out a certain minimum amount on both sides of the centre line of my gerber edge cut?

author: NivagSwerdna
author_rank: Super Contributor
timestamp: November 05, 2020, 04:41:22 pm
content: Section 17 ofhttps://support.jlcpcb.com/article/68-instructions-for-orderingI think this is saying they use 1mm bit and therefore I would lose .5mm on each side of the centre line? and it would end up rounded slightly in the corners?

author: Benta
author_rank: Super Contributor
timestamp: November 05, 2020, 04:54:25 pm
content: Normally such cutouts are specified in the outline file. This means that the router will compensate for bit diameter. You don't need to think too much about it.Square corners are normally not possible without laser or jet cut, but a workaround is to let the router "overrun" in the corners so that "pouches" are cut.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: November 05, 2020, 04:55:49 pm
content: Quote from: Benta on November 05, 2020, 04:54:25 pmAh perfect!
Slots in PCBs - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: November 17, 2019, 12:13:51 pm
content: I would like to cut a slot in my PCB through which another PCB will slot at 90 degrees.... Which got me to wondering...What constraints exist in practice when making slots?Can they really have square edges or should they be rounded?I looked on the JLPCB web site but couldn't find any guidance.In my example I need a slot through which a PCB would fit... The PCB being 37mm wide and 1.6mm thick.I presume I would need to allow wiggle room too.Does anyone have any wisdom they could share please.ThanksNivag

author: Jeroen3
author_rank: Super Contributor
timestamp: November 17, 2019, 12:16:24 pm
content: Usually the milling tool is 2mm. So the minimum width is 2mm. Square corners will also be at 2mm radius.Less is possible, but requires an extra step at higher price.And you have to keep enough rigidity in the board to be able to mill and pick&place. This depends on the design.

author: Miti
author_rank: Super Contributor
timestamp: November 17, 2019, 12:38:37 pm
content: They use router bits for slots and those are, obviously, round. So you can have square outer corners but rounded inner corners but that’s ok as long as the flat part of the slot has the same length as the board you put through. As for the wiggle room, the board thickness may vary a bit, mainly with the finish. Immersion gold is more consistent, hasl is bumpy, for example. For my projects I make it tight and, if needed, a small file does wonders.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: November 17, 2019, 02:01:13 pm
content: So say I just went for a 2mm wide slot... It would have semi circles at both ends .. should I submit a board outline layer which has the arcs?(Currently I have a 1.6mm X 37mm rectangle with no wiggle room)

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 17, 2019, 07:00:41 pm
content: You can make a dogbone shape so the board registers against a flat end stop in the slot.They'll rout smaller slots too, but there may be added cost; 2mm is just the most common end mill.mikeselectricstuff also did a video about doing this at minimum cost, where you make a somewhat zig-zag pattern so the board is sprung between faces with the correct spacing, without requiring a smaller end mill.Tim

author: IanJ
author_rank: Unknown
timestamp: November 17, 2019, 07:29:35 pm
content: Quote from: NivagSwerdna on November 17, 2019, 02:01:13 pmMy 2mm slots are drawn rectangular, but as the fab uses 2mm bits the holes come out perfectly rounded at the ends.....so in reality there is a tiny bit of the pcb left on the board at each corner of the slot. They don't go over the line.Note: Pcbway will do down to 0.8mm as a special.Ian.

author: Miti
author_rank: Super Contributor
timestamp: November 17, 2019, 11:13:27 pm
content: Quote from: NivagSwerdna on November 17, 2019, 02:01:13 pmMake it 1.6mm and submit. If they want more money or reject it, they'll let you know. Your mechanical strength is reduced with a wider slot the assembly relies only on the pads/solder.
Slow Blow or Fast Blow fuse? - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: September 22, 2020, 06:54:28 pm
content: Hi,with reference to the attached schematic, would you recommend a slow blow or fast blow?I was thinking that when initially the circuit receives power C14 and C15 are discharged and there might be a (relatively) large current surge. So a slow blow fuse might be better?But then again the current surge might be too short to need a slow blow?Or maybe I should think in a different way when coming to choose the type?Thank you

author: Benta
author_rank: Super Contributor
timestamp: September 22, 2020, 07:39:33 pm
content: Doesn't matter. You'll never have more than 13 mA running through it.

author: ricko_uk
author_rank: Super Contributor
timestamp: September 22, 2020, 08:45:16 pm
content: Thank you Benta,I got that schematic from a reference design. The fuse is set to 1A, I assume in case any components downstream fail. What do you mean never have more than 13A?Do you mean because R11 and R12 would limit the current? I thought the fuse is there perhaps in case R11 and R12 short?Sorry but not much experience in mains design and requirements.Thank you

author: james_s
author_rank: Super Contributor
timestamp: September 22, 2020, 09:43:58 pm
content: 13 *milliamps*, that's 0.013 amps. You've got 30k worth of resistors in series which will limit the maximum current according to Ohms law. I would consider just using flameproof resistors and skipping the fuse.

author: Benta
author_rank: Super Contributor
timestamp: September 22, 2020, 09:44:49 pm
content: The fuse is good practice (and depending on your electric code rules) for fire protection. It's not there to save your circuit.

author: james_s
author_rank: Super Contributor
timestamp: September 22, 2020, 09:50:32 pm
content: They make flameproof resistors that are designed to function as a fuse, sometimes they're called fusible resistors. They're quite common in low power applications like that.
Slow rise time on switch  - Page 1
Forum section: electronics / projects

author: Guitar760
author_rank: Newbie
timestamp: August 13, 2015, 11:32:00 pm
content: I'm feeding the clock input of a D-Type Positive edge triggered flip flop with a momentary switch on a 5v rail, using 100k ohm for debounce. For the most part, the flip flop won't change states - every now and then it will actually switch but for the most part, nothing.I hooked it up to my DSO and measured my rise time to be 700 microseconds, so I'm thinkinging it's just too slow for the flip flip to register as a clock input.Is there a way to speed up the rise time, maybe with a transistor fed from the switch? I'm very limited on space, working a 15mmx18mm board

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 14, 2015, 12:23:47 am
content: Add a Schmidt trigger (e.g. 74HC1G14) in front.What do you mean "100k debounce"? A resistor alone does not provide this function. Typically a switch or pushbutton is debounced by placing a large capacitor in parallel with the switch (0.1uF is typical), and using a large pull-down resistor (like 100k) so the voltage takes a long time (~10ms) to return to zero after the last contact bounce occurred.Tim

author: merlinb
author_rank: Contributor
timestamp: August 14, 2015, 11:37:00 am
content: If you can replace the IC then you could substitute a D-type variant with built-in Schmitt triggers, such as:http://www.farnell.com/datasheets/1724714.pdf
Slow Scan pixel by Pixel xray Image with home parts. - Page 1
Forum section: electronics / projects

author: spaceballs
author_rank: Newbie
timestamp: May 07, 2023, 01:19:57 am
content: A random project I recently concluded, by using a fire alarm (for xray source), a Geiger-counter (actually a gamma spectrometer), 3d printer, and bismuth block (with pin hole in it) to make xray images. The results aren’t too bad, though takes long time for a scan. I was thinking maybe making a cheap open source system, but my wife later told me at her work that xray machines are now super cheap now (which I didn’t know) so guess it’s an dead idea.It's pretty much a simple system, I used the 3D connected to a PC sending gcode to move the bed, and software connected to the geiger counter to read counts.

author: freshstart
author_rank: Newbie
timestamp: May 07, 2023, 03:46:31 am
content: this sis cool did u get it programmed UP IF YOU NEED ANY HELP IM A dEV

author: james_s
author_rank: Super Contributor
timestamp: May 07, 2023, 04:02:35 am
content: Quote from: freshstart on May 07, 2023, 03:46:31 amHopefully your code is more readable than your forum posts.
Slowing a movie down - Page 1
Forum section: electronics / projects

author: PinheadBE
author_rank: Regular Contributor
timestamp: March 20, 2023, 09:31:50 pm
content: Hi,I have some older Android tablets laying around, and I would like to recycle them in slow motion video players the easy way.Unfortunetaly, I did not find a tool online that could play a video file slower than 0.25 x nominal speed. Even the ubiquitus VLC cannot do better than 0.25 x on Android while it can go down to 0.02 x on Windows.... Go figure.....Any ideas ?- A program that slows down the framerate before playing ?- An Android player that can go far under 0.25 x ?- A program to convert a video file in individual pictures and then another "picture player" that would change the picture once per 10 seconds, for example ?I have trouble to believe no one ever tried that with those old tablets laying around.....Thanks in advance

author: RoGeorge
author_rank: Super Contributor
timestamp: March 21, 2023, 08:36:16 am
content: Don't know about tablets, but on a PC, either VLC or MPV can play even at 0.01 speed. The shortcut keys to change the speed are '[' for slower or ']' for faster, press repeatedly to keep decreasing/increasing.For other processing, read the manual for 'ffmpeg', or search online for command line examples to do whatever you need.

author: freda
author_rank: Regular Contributor
timestamp: March 21, 2023, 09:05:38 am
content: set your desired slow speed with VLC and record it.then see how the result file plays on the android?

author: AndyBeez
author_rank: Frequent Contributor
timestamp: March 21, 2023, 09:23:23 am
content: Convert your video files to a different frame rate using the well supported audio and video tool FFMPEGhttps://ffmpeg.org/about.htmlKeeping it simple, you can also playback .MP4 files through a custom web page in Android Chrome.VLC has good support but, the Play Store may not have a back dated version for your tablets OS's.

author: mariush
author_rank: Super Contributor
timestamp: March 21, 2023, 09:30:08 am
content: Virtualdub (and the newer modded versions with support for mp4/mkv input) support changing framerate with or without changing time (ex convert 30fps to 10fps, or stretch 30fps into 3 seconds at 10fps)But, it requires recompression of the video.

author: Martin Luther
author_rank: Newbie
timestamp: April 22, 2023, 04:42:09 am
content: VPlayer and MX Player are two Android video apps that can do this. Both of them let you slow down the playing speed and even let you fix the pitch of the sound. FFmpeg is also a command-line tool that can help you change the framerate of a movie.
SM 12 device on a circuit - Page 1
Forum section: electronics / projects

author: tytower
author_rank: Contributor
timestamp: February 27, 2020, 05:33:54 am
content: I have a circuit with a dc photovoltaic string of about 280 volts feeding into this. The circuit calls for a SM12 chip with I think 4 pins. I guessed it was a voltage regulator of some kind but all the googled datasheets give different devices and none seem to fit this .Can anyone tell me what it would be and where I would get one?Its marked Pin 1 is L, Pin 2 is N, Pin 3 is +12 v, Pin 4 is 0 vI Just noticed in the notes he says " A small Chinese postage stamp sized 12v dc power supply provides power ."Could these two be the same thing . Its input would be 280 Volts DC so I am at a loss here.

author: Ian.M
author_rank: Super Contributor
timestamp: February 27, 2020, 07:28:05 am
content: Yes, it could well be a SMPSU module intended for wide range AC input (e.g 100V to 240V AC) as a SMPSU without input power factor correction will usually run from DC with an input range of 1.4 times its AC rating (so 140V to 340V DC for the example range given).To decide if a particular SMPSU is suitable, after checking its input range converts to include the DC supply voltage, check the SMPSU's circuit - if (ignoring fuses and NTC inrush current limiters) its AC input goes straight to a bridge rectifier with a 350V or higher electrolytic reservoir cap immediately after it, odds are it will be suitable. Anything with a startup circuit or sensing circuit or similar tapping off the AC before the bridge rectifier will *NOT* be suitable.N.B. any on-board fuse will *NOT* be DC rated so to avoid a serious fire risk, an external DC rated fuse, with sufficient voltage rating *MUST* be used.
STM32 based oscilloscope project could become very useful w BT/Wifi - Page 1
Forum section: electronics / projects

author: cdev
author_rank: Super Contributor
timestamp: November 04, 2017, 02:58:30 pm
content: The super cheap STM32F103 oscilloscope over on stm32duino looks promising.http://www.stm32duino.com/viewtopic.php?t=107Its a huge thread with lots of people contributing their improvements.. with photos of their implementations, Like the AVRTransistorTester.If they successfully add wireless connectivity to it it would really fill a need - as shown by the recent thread on the Velleman unit.An open STM32 project could be what the Velleman project isnt.I would love to have an open wireless o-scope.
Smal Display modules - Page 1
Forum section: electronics / projects

author: k7-3d
author_rank: Newbie
timestamp: August 25, 2013, 08:53:48 am
content: i have an old 4,5 Digits LCD (Epson LD-B1023) but the zebra pins are damiged is ther any other modules that are so small as modules? for i have very limitid spasemodule size: LxH 40mm x 18mmthe max size in the project is: 42mm x 20mm
Small alternative to MLCCs that don't whine - Page 1
Forum section: electronics / projects

author: leonerd
author_rank: Regular Contributor
timestamp: February 14, 2018, 12:14:39 am
content: I have an application of the ICL7660 (or 7662) charge pump chips, for creating a negative rail for an op-amp. Currently on my board I'm using 1206-sized 10µF MLCCs, which seem to work well enough electrically, but they cause quite a noisy whine due to the piezo effect of MLCCs.Can anyone suggest something suitable to use instead of these that wouldn't create that noise? A regular through-hole electrolytic would be quite physically large at this value (10µF at 15V). Are SMD aluminium electrolytics much smaller? Failing that I suppose there's the tantalums, but I gather those are prone to explosions and fire - not sure I want to deal with that.Any other options?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 14, 2018, 12:20:06 am
content: Tantalum Polymer caps don't have the same fire issues. Also Aluminium polymer.Both are rather expensive.The sort of current levels in a 7660 circuit aren't likely to be problematic fire-wise for normal tants though.There are some lower-noise ceramic variants, but when I tested some they didn't seem to be that much better.

author: KE5FX
author_rank: Super Contributor
timestamp: February 14, 2018, 12:23:48 am
content: Tantalums should be fine. They aren't all that prone to explosions and fire if you derate them properly and don't expose them to high dI/dt conditions. A charge pump application will be perfectly safe.If you don't need more than -5V or so, you might also look at newer charge pump ICs like the LM27761. These run at much higher frequencies.Along those lines, it's possible that the reason you're hearing the whine is because you're not drawing enough current from the charge pump to let it run in continuous-duty mode. See if the problem goes away with some additional load resistance?
Small assembled connectors for TXL wire - Page 1
Forum section: electronics / projects

author: rcbuck
author_rank: Frequent Contributor
timestamp: July 10, 2025, 12:29:26 am
content: I need a 14 conductor board to board connector. It needs to use either silicone or TXL wire as I have to meet 125 degree C rating. The connector needs to be small, no larger than 1.25 mm pin pitch if possible. I could live with 2.0 mm pitch if absolutely necessary.Does anyone make this type of cable assembly? I don't mind placing the wires in the housings if that is the only solution.I found this on AliExpress:JST PH2.0mm Pre-Crimped Silicone Cable Wire 22AWG Copper Wire High Temperature Resistance Cable Crimp Terminals PHR2.0 ConnectorI'm guessing these wires are for the JST PHR connector housings. The datasheet for the JST housing says it is made for AWG #32 to AWG #24. I suspect the 22AWG on AliExpress refers to the diameter of the wire including the insulation. Ali sellers are sneaky about this sort of thing. #32 AWG wire size would work for my application.Suggestions?
Small audio "mixer" ? - Page 1
Forum section: electronics / projects

author: TomS_
author_rank: Frequent Contributor
timestamp: September 05, 2015, 01:09:14 pm
content: Hi everyone, apologies for what must sound like an incredibly basic question, but electronics were never my forte as much as I wanted it to be.Basically I have a motorbike. I go riding with friends quite often, and we record a lot of video. We also use CBs to talk to each other while riding (with speakers and mic in our helmets, and a PTT button on the handlebar kind of setup.)I'd like to be able to combine the audio sources from the in-helmet mic and the CB output and pipe them in to the camera to record our conversations. I would also like to take the audio from the mic in to the CB.Ive attached a photo of this which might help to make it clearer.Im just not 100% sure about the best way to go about this.Could it be as simple as using some diodes to "mix" the signals and direct them the way I want them to go, or would I need to use some amplifiers in the middle of it all? Im guessing the later, in particular for the mic in the helmet.I was watching Daves video on op amps the other day, and I am wondering if a tiny battery powered circuit using one of them would provide sufficient output to feed the radio (momentarily in-circuit) and camera (permanently in-circuit)? Would I also need one to provide extra power for the output from the CB? Or am I looking at the wrong kind of device for that?If you have any pointers I'd greatly appreciate it.Thanks

author: German_EE
author_rank: Super Contributor
timestamp: September 05, 2015, 05:40:15 pm
content: The 'magic' in your diagram is complex but possible:Audio sources first1) Audio from the CB is split between the headphones and the camera, easy, two resistors. Start with 8 ohms for the headphone lead and 1000 ohms for the camera and if something is too loud then increase the resistor value by about 10% and try again.2) Audio from the microphone is split between the CB and the camera, easy, two resistors PROVIDING the output from your microphone is high enough so an extra amplifier may be needed here. Start with 1000 ohms eachNow the audio input3) The camera is fed from two inputs, the CB and the microphone, join the resistors from the CB and the microphone together and just feed them into the audio input.One more thing, think about some sort of quick disconnect on your helmet lead for when you fall off. Being strangled or getting your neck broken by the trailing lead is not the best way to go. Look at a police bike for some ideas here.Diodes are not the way to go because they are used to rectify a signal and it will sound distorted.
Small batch production and proper ESD component storage - Page 1
Forum section: electronics / projects

author: mcinque
author_rank: Unknown
timestamp: February 13, 2015, 12:46:00 pm
content: I'm going to build soon a small batch of circuits and I have a BOM with some TPH ESD components inside.These ESD "sensitive" components (according to their manufacturers) are :schmitt triggeratmel mcuquartz crystal oscillatorsome TVSsome 1N4xxx diodesdc-dc converterIRF & ZVN mosfetsTO-100 linear regulatorsI'd like to have a box with all the BOM components properly organized ready to be picked for the thru hole placement .For all the NON ESD compoents (passives, small parts, screws, fittings) I normally use this:which is made of polystyrene.. of course not the suggested material for static control...But I must say that for many months I've used that kind of box to store ESD sensitive components without any apparent issues.Since AFAIK ESD damage is NOT limited to simply kill a component (so you could have a dead circuit or not), but it can dramatically shorten it's life (and therefore you can ship many circuits that will fail in X months), I wonder if I must purchase a proper ESD box to store the sensitive parts or if this it's something that you must do only with a 10.000 pcb mass production.In my "lab", the RH is 52-65% and I normally use a properly grounded ESD mat.I think that the ESD sensitive components I have in my BOM are NOT so sensitive, otherwise, since they are much common, many of us would have dead circuits (I see how my friends store their parts!).What do you suggest? How much of you have experienced issues with ESD, that common components and a small batch production?

author: rdl
author_rank: Super Contributor
timestamp: February 13, 2015, 02:43:37 pm
content: Just about any device that uses MOS technology is going to be static sensitive. All but a couple of the items on your BOM definitely, probably or maybe use MOS technology. When in doubt, follow the manufacturer's recommendations.

author: lapm
author_rank: Frequent Contributor
timestamp: February 13, 2015, 10:26:09 pm
content: If this is product you manufacturing for sale, take precaution recommended by manufacturers. And after you are done, you still have those esd safe containers for next project..

author: zapta
author_rank: Super Contributor
timestamp: February 14, 2015, 02:48:28 am
content: I wouldn't keep them loose in non ESD box. My situation here is similar and I keep the components in plastic dissipative bags (pink) stored within a metal candy box. Another option is inserting them into those ESD foamsESD damage is not all or nothing, sometimes the damage partial and your boards will still pass the test.
Small beginnings to brag about. - Page 1
Forum section: electronics / projects

author: JDS
author_rank: Newbie
timestamp: May 10, 2015, 10:14:07 pm
content: Hi,This is my first posting and I want to thank the community in general and Dave in particular for giving me the courage to start messing with electronics. After watching Dave's vid on soldering I bought some decent soldering equipment and started fixing a few things in the shop. First was the DRO for my lathe. The linear scales are wired to the display using RJ11 PCB jacks. These were in bad shape and needed to be replaced. Using a hot air gun I melted the connections to the pins and removed them in one go. Inserting the replacements and soldering them in place was a snap. Impressed with my newly acquired skill I went on to diagnose and fix my son's electric guitar (the pickup jack was broken). These 2 small projects alone probably paid for the price of the soldering equipment and opened up a whole range of possibilities. Next, I think I am going to help my son with one of his projects which is building a DIY (monster) portable sound system for his performances. I'll never be an engineer, but a little knowledge and a bit of common sense/caution can go a long way.

author: tautech
author_rank: Super Contributor
timestamp: May 10, 2015, 10:48:40 pm
content: Welcome to the forum.Good on you, easy isn't it?Good luck on the endless path.......

author: xrunner
author_rank: Super Contributor
timestamp: May 10, 2015, 11:04:02 pm
content: Quote from: JDS on May 10, 2015, 10:14:07 pmAwe - some!QuoteIt sure does!

author: Dragon88
author_rank: Regular Contributor
timestamp: May 11, 2015, 01:21:20 am
content: When I was a kid I played with toys. Then I got a little older and played with more expensive toys. Now I make my own toys.That's how I see electronics. It's a lot of fun.
Small BMS for LiFePO4 Float System? - Page 1
Forum section: electronics / projects

author: edpalmer42
author_rank: Super Contributor
timestamp: April 25, 2022, 09:39:17 pm
content: I'm looking for a small (1 or 2 amps, maybe 5 - 10 AH capacity) BMS for an LiFePO4 battery backup system operating in float mode.I have 5 or 6 devices that had internal battery backup. They were either Lead-Acid or Ni-Cd based. I'd like to upgrade them to LiFePO4, but I haven't been able to find a suitable BMS. They all have inputs for an external 24V battery system and that's also what their internal battery packs are designed for. Small 8S BMS boards are easy to find, but since the batteries are floating, the voltage has to be lowered to about 3.3 - 3.4V rather than the normal charge voltage of 3.65V per cell. A large, high power, programmable BMS can do this, but that would be total overkill for this project.I've also thought of building an external 24V system that could power all the units, but I don't see that as an upgrade to my current arrangement of plugging them into a big UPS. The internal batteries would make them somewhat portable, even if it was just for equipment rearrangements. These devices are precision frequency sources that youreallydon't want to lose power, even for a few seconds.So does anyone know of a source for a small BMS that either is set for 3.3 - 3.4 V per cell or is adjustable - probably via a pot? Is there another way to accomplish the same thing?Thanks,Ed
Small but usefull project - HP6623A Addon - Page 1
Forum section: electronics / projects

author: xchg.ca
author_rank: Contributor
timestamp: November 07, 2014, 04:11:07 am
content: Hi guys, want to share with you mu recent project.This is external binding posts addon to HP 6623A 3 output power supply.3d printed contraption can be attached on either side of the PSU. 3xM4 screw attach box very securely to the side of the PSU.Box has 6 holes matching Pomona binding posts cutouts. 3mm walls make box quite sturdy.Wire go all the way to the back. Sense wire not really necessary because top current is 4A, drop wont be that big. But I will add them eventually.Here are all photos:https://plus.google.com/photos/103976720797990893155/albums/6078808653897687617If you interested to do something like this here is STL file attached.Future improvements: add 3 switches to enable-disable each output via Relay Option my PSU has.
Small capacitance sensing board for pressure sensors - Page 1
Forum section: electronics / projects

author: frasdoge
author_rank: Contributor
timestamp: July 10, 2021, 11:26:52 am
content: Hello,Day to day I work on testing capacitive pressure sensors for our lab in the range of 5 - 200 pF. One application of our sensors is to measure pulse rate. We can do this by strapping a sensor to the wrist like a watch, though the wires still go off to a bench LCR meter. We can then find pulse rate by performing an FFT. What I'd like to do is make this field portable by having some capacitance sensing electronics in the casing of the "watch" to record to an SD card.There are few issues with going about this that I need some advice on.Firstly, the choice of capacitance sensing method. My idea at the moment is to have a micro generate a 1 Vpp 1 kHz sine wave from either a built-in or external DAC, buffer / amplifier if needed, current sense resistor, followed by our sensor. Then use an ADC over the resistor for current, over the capacitor for voltage, and use V = I/jwC to get the capacitance. If the series resistance needs to be accounted for I could instead measure the peaks and phase difference between the current and voltage and work backwards from impedance to capacitance. Is this a good way of going about it?Secondly, I've not implemented a micro myself before. I've only programmed dev boards where everything has been plug and play. To fit everything into the size constraints (~ size of a watch) I think I would need to make my own but it's intimidating. Especially for connecting my own programmer (never used JTAG, and it looks large profile) or an external crystal. If there are any great tutorials I'd appreciate being directed to one.Cheers,Fraser

author: frasdoge
author_rank: Contributor
timestamp: July 11, 2021, 06:13:01 am
content: Thanks for the depth of the reply!I'll have to spend quite a bit of time digging through this to decide what will work best for me, but the FDC2x1x option is looking very appealing. I'll just need to fit in my numbers to see what sort of resolution and range I'll get. Any MCU with I2C should be able to handle it. If it doesn't do the job I'll stick with the sine generation and possibly the AD5940/1 impedance measurement.On the front of MCUs, is there much added complexity or power draw going with a 32-bit like the PSOC5LP you suggested? It seems very over spec for what I need but if it fits in with size, complexity, and power draw requirements I don't see a reason tonotuse it. Benefit being I'll have options if I change my mind. I figure I'll be powering this off a 2032 cell and boost converter.