hybridfree/eevblog-posts huggingface dataset:
EMI pickup device (mailbag) - Page 1
Forum section: electronics / projects

author: SGI
author_rank: Newbie
timestamp: March 03, 2019, 10:20:16 am
content: Hello Dave's aficionados!A tough question for you... Once upon a time in the Mailbag section somebody sent in an homebrew device which only purpose was...picking up EMI from electric/electronic appliances!Sorry I'm unable to provide any more info... I just remember that this cute gadget could tune in on EMI by swiping it all over the device under test!I'm into electronic music and from time to time - in my earphones - I can barely hear this noises that sometimes has excellent rhytmical features!Unfortunately I can't amplify them enough to be usable in my "choons"!Sounds weird, huh?I'd love to buy the kit to build that!!Have a nice day,Francesco

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: March 03, 2019, 10:45:34 am
content: H-field probe into a suitable instrumentation amplifier maybe?Check Daves videos from one / two weeks ago where he DIYs one of those from coax and recommends a decently cheap amp.

author: SGI
author_rank: Newbie
timestamp: March 03, 2019, 12:31:52 pm
content: I'll check that!Maybe Dave himself would remember?Or the creator of the instrument??Cheers

author: magic
author_rank: Super Contributor
timestamp: March 03, 2019, 01:15:21 pm
content: Frankly, you could just record it from the headphone jack of whatever device you have which picks it up.

author: Fire Doger
author_rank: Regular Contributor
timestamp: March 03, 2019, 01:17:16 pm
content: https://www.eevblog.com/forum/blog/eevblog-1178-build-a-$10-diy-emc-probe/Are you referring to noises similar with the sounds made when you make a call near a cheap speaker?
Emitter Follower - Page 1
Forum section: electronics / projects

author: Navytron
author_rank: Newbie
timestamp: September 28, 2014, 12:04:00 pm
content: I am trying to amplify a 1.5 micro second one shot multivibrator output with a a PNP emitter follower. A simple inverter is used to properly feed the PNP emitter follower, and the chip seems to be working okay. I have my 1.5 micro second pulse on the base of the transistor but I'm getting .5 micro seconds square wave out the collector. To make things worse after the trailing edge really slopes down almost like the load is causing the voltage drop. I've verified the load is okay. Note. The one shot multivibrator is used as a delay pulse that is later fed into a video card. Any ideas??

author: Andy Watson
author_rank: Super Contributor
timestamp: September 28, 2014, 12:16:02 pm
content: Schematic would help.

author: Navytron
author_rank: Newbie
timestamp: September 28, 2014, 12:38:44 pm
content: Ask and you shall receive.

author: Andy Watson
author_rank: Super Contributor
timestamp: September 28, 2014, 12:44:46 pm
content: Looks like it should work. What value resistors ? And, what load?

author: Navytron
author_rank: Newbie
timestamp: September 28, 2014, 12:54:35 pm
content: collector 1k, base 330, load 1k, 5V supply 12k

author: Andy Watson
author_rank: Super Contributor
timestamp: September 28, 2014, 01:02:55 pm
content: You could reduce the value of the 12k. You only need about 0.7V developed on the base-emitter. Calculate the value to give slightly in excess of 0.7V B-E, this will also reduce the driving impedance and should speed things up.

author: Marco
author_rank: Super Contributor
timestamp: September 28, 2014, 02:02:01 pm
content: Common emitter amplifier, not emitter follower. Also I'd call it a level shifter instead. Why not use a NPN with an emitter resistor instead of the inverter? This avoids the need for the precisely matched resistor divider, you just slam the PNP on and the pull up turns it off ... if it's still too slow add some emitter degeneration on the PNP too (this will increase output impedance though).Likethis(second google image search result on PNP level shifter by the way).

author: Navytron
author_rank: Newbie
timestamp: September 30, 2014, 11:09:11 pm
content: Sorry for posting a little late. I think the original gripe 1.5 micro second low pulse on base of transistor resulting in a .5 microsecond pulse out May have been caused by the bias of the emitter base junction.
Emitter voltage undershoot and other creepy bits - Page 1
Forum section: electronics / projects

author: asgard
author_rank: Regular Contributor
timestamp: February 16, 2012, 06:02:04 pm
content: Enclosed here I have put a zip file with an LT-Spice netlist, and associated plot of the simulation.This circuit represents a portion of a project I am working on which has a fairly large array of LED's ina Charlieplex configuration. The top power is the driving source on the collectors of the switching transistors. The bottom two are configured to drive the transistor bases as a two-bit binary counter.I have some questions regarding the plot of the Spice run.1. The current switches are turned on only when the two bits of the counter differ (XOR function).The voltage at the emitters don't seem to be similarly limited. Each one will experience a one-bit timeperiod where the voltage at the emitter is elevated past the LED turn-on level, yet the indicatedcurrent is near-zero.2. The simulation shows the emitter voltages have an undershoot of nearly -0.3V at the falling edge ofthe pulse when simultaneously the diode current pulse is also turned off.3. Correct me if I'm wrong, but the the emitter voltage drops about 0.7V when the diode current is turned on. Is this the result of the base-emitter junction forward voltage drop?You all can probably tell I am not normally an "analog" guy, right?

author: Unknown
author_rank: Unknown
timestamp: February 16, 2012, 06:39:52 pm
content: Posting a screenshot with the relevant details makes it easier for people to see your problem without having to download your circuit. I attached one for convenience.Quote from: asgard on February 16, 2012, 06:02:04 pmIf both the base and emitter are at approximately 3.3V, no current will flow through the base, and hence through the emitter.Quote from: asgard on February 16, 2012, 06:02:04 pmCapacitance of the diode junction? Putting a small cap in series makes it worse. This would be basically a tiny version of a switched cap circuit as used for charge pumps.Quote from: asgard on February 16, 2012, 06:02:04 pmYes. The 3.3V when both are turned on is probably collector-emitter leakage through the transistors.
eMMC Flash Memory retention/reliability  - Page 1
Forum section: electronics / projects

author: rakeshm55
author_rank: Regular Contributor
timestamp: July 26, 2018, 01:13:30 pm
content: Hi,If I want to operate an eMMC memory at high ambient temperature say (70C to 75C) will it severely degrade the performance of the device over long time.. What kind of failures I can expect in long term??.....We are expecting a continuous operation of about 10hrs/day... through out the time device will be stressed at 75C....Updates/writes to this memory will be rare ... this memory will be used for u-Boot and OS components...

author: amyk
author_rank: Super Contributor
timestamp: July 27, 2018, 02:10:15 am
content: At those temperatures the leakage rate from the cells will be much higher, so you'll essentially have self-erasing flash. Unfortunately (depends on the exact eMMC, but I believe the majority of them are like this) the firmware for the flash controller itself is stored in the same flash, so this isn't just a matter of "rewrite periodically".

author: tsman
author_rank: Frequent Contributor
timestamp: July 27, 2018, 02:33:47 am
content: You can buy extended temperature range eMMC. Look for automotive grade that has a 105C maximum temperature. If ambient temperature will be 70-75C then you probably shouldn't risk using the 85C maximum temperature parts.

author: rakeshm55
author_rank: Regular Contributor
timestamp: July 30, 2018, 10:57:34 am
content: Typical NAND flash memory and retention in the attached image... at 75C it is hardly one year....eMMC does it have any algorithms to detect leaking cell and correct in on the fly ... So that the data is replenished??
EMP Jammer  - Page 1
Forum section: electronics / projects

author: Kedar264
author_rank: Regular Contributor
timestamp: February 09, 2015, 03:31:14 pm
content: Emp Jammer can jam most of electronics, see how i made my own emp jammer which can jam my cdma cell phone network easily,calculator seems to not work nearby emp jammer, tell me your ideas and thoughts

author: Stonent
author_rank: Super Contributor
timestamp: February 09, 2015, 04:52:10 pm
content: Illegal in most countries.

author: wkb
author_rank: Super Contributor
timestamp: February 09, 2015, 06:22:13 pm
content: Quote from: Stonent on February 09, 2015, 04:52:10 pmAnd a good thing that is too!
Empirical physical transformer to spice model tool - Page 1
Forum section: electronics / projects

author: jpyeron
author_rank: Regular Contributor
timestamp: October 08, 2022, 05:19:09 pm
content: i have found a few tools out there to create SPICE models of transformers. But I have not found any that can easily allow adjustments for real (measured) parasitic parameters.Anyone have thoughts? Should I go off and build one?

author: Slh
author_rank: Regular Contributor
timestamp: October 08, 2022, 06:29:14 pm
content: What sort of parasitics? It's easy enough write a model with leakage inductance, magnetising inductance and DC resistance.The trouble comes when you want to add saturation and ac resistance.

author: jpyeron
author_rank: Regular Contributor
timestamp: October 08, 2022, 07:22:12 pm
content: There are 2 use cases that comes to mind.1. I have been working on some switch mode power supply circuits - I buy the cores, wind them, but obviously have differences from ideal. I would like to update my circuit simulations.2. (a just because) I have 100s of new/old coils and transformers laying around, would like to model them.

author: jonpaul
author_rank: Super Contributor
timestamp: October 08, 2022, 09:00:40 pm
content: models need parasitic capacity p..s, p...earth, s..earth, shield, etc.At RF resistance must include skin effectWe used Magnetic Designer from IntuiSoft, creator passed away, it is now freeJon
Empty Reels - Page 1
Forum section: electronics / projects

author: itdontgo
author_rank: Regular Contributor
timestamp: May 17, 2021, 02:33:51 pm
content: My technicians always keep the empty reels once they're finished in the P&P machine.Can we recycle them or return them or is it just bin time?It seems to be a waste. We're in the UK

author: Benta
author_rank: Super Contributor
timestamp: May 17, 2021, 04:28:42 pm
content: Many reels carry a deposit that can be redeemed.
Emulating a 1970s PMOS serial ROM with a modern microcontroller.  - Page 1
Forum section: electronics / projects

author: Bob-O-Rama
author_rank: Newbie
timestamp: February 28, 2023, 08:31:18 pm
content: Hi,I am trying to replace a PMOS based serial ROM ( see bottom ofhttp://www.datamath.org/Chips/TMC0540.htm) used in old TI calculators with a modern micro-controller. Specifically the TI-59's user replaceable "Solid State Software" modules. This PMOS ROM has Vss = GND, Vdd = -10v, and Vgg = -16v.Assuming the microcontroller board can be powered by > 6v, can it just be floating between Vdd and Vgg? Ideally I would like something I can cram into the form factor of the Solid State Software module, which is a bit bigger than a 8-pin DIP - and preferably something that could have bluetooth for programming the "ROM" while the calculator is operating.Thanks for any suggestion.-- Bob
Emulating HP 372x PRNG, LFSRs, and Spectrum Display - Page 1
Forum section: electronics / projects

author: somejoe
author_rank: Contributor
timestamp: August 01, 2025, 04:30:09 am
content: As part of the effort to build an HP-3722, it would be worthwhile to examine other versions of this instrument.The "H01" version provides a Delay Code [0 0 0 +] mechanical counter on the front panel.HP application note AN98-2, "Noise at Work A point by point correlator for the H01-3722A", 1969,states that:"Selection of the shift register outputs to be added is performed by a group of decade switches on thefront panel. These switches, which are set according to a conversion table supplied with the instrument,provide a useful number of delays ranging from zero to the number of bits (N) in the sequence in use".So I am looking for a copy of the conversion table and/or the service manual for the "H01" version ofthe 3722A instrument.
Emulating lithium battery - Page 1
Forum section: electronics / projects

author: Jussi
author_rank: Newbie
timestamp: August 26, 2023, 08:05:31 am
content: I have several RF modules that work with CR2025 lithium batteries 3 in series. Some of them freeze randomly at low batteries but the other works with the same batteries without problem. In addition, when the battery capacity has decreased slightly, the same module works normally again.Is it possible to emulate a low battery with a adjustable power supply e.g. using a small resistor in series and limiting the current and voltage to find to find in which points the problem occurs?

author: mikerj
author_rank: Super Contributor
timestamp: August 26, 2023, 01:01:28 pm
content: The RF modules are probably drawing bursts of current so cell impedance would play a part, and this will vary somewhat with depth of charge. If some modules work and some don't with a same battery, that could be a sign that the supply decoupling on the bad modules is not effective e.g. bad electrolytic capacitors if they are used.Looking at battery voltage with an oscilloscope on good and bad modules (whilst operating) would be more instructive then trying to emulate the batteries IMO.

author: Siwastaja
author_rank: Super Contributor
timestamp: August 27, 2023, 05:59:56 am
content: Series resistor is a fair approximation. Remember, the colder temperature the battery is at, the more equivalent series resistance it has.
Emulation Technology AS-160-48-01F-600 adapter - Page 1
Forum section: electronics / projects

author: ehobby
author_rank: Contributor
timestamp: March 13, 2024, 12:49:09 am
content: I am looking for the spec or pin-out mapping and socket type for the Emulation Technology AS-160-48-01F-600 adapter. It is used with devices like the CY7C375. The package may be identified as an MCR 160, G160 or U160. I think it is a military flat pack based on the F in the part number. The ET part number is correct but I cannot find the spec.It you have a spec for this programming adapter, please pass it along.Thanks
EN 50005 relay contact naming convention -- previously head EN 50011 aka BS 5583 - Page 1
Forum section: electronics / projects

author: Cicada
author_rank: Regular Contributor
timestamp: July 31, 2021, 08:27:01 am
content: HiI looked at 11 pin relays recently and for the first time noticed the pin numbering scheme. See attached picture for this example,For example, for the same contact (i.e. same sequence number = 1) the pins are 11 for common 12 (NC) 14 (NO) If this single pole double throw was implemented with 2 switches (double pole single throw) the terminals would have been 11 & 12 for (NC) and 23 & 24 for (NO)I was surprised I never really noticed this. It lead me to this standard.http://webshop.ds.dk/Files/Files/Products/22195_attachPV.pdfonly first page shownhttps://www.scribd.com/document/282455490/Documentthis shows the standard is only 12 pages long.Has anyone seen this entire standard and can you recall if there are more things to be known from this standard?40 Euro for the standard is a bit muchMaybe there is a good app note that you can point me to that discusses all/most of the things defined in this standard.CicadaADITION TO ORIGINAL POST.I have attached a picture from another OMRON datasheet showing the pin numbering for a contactor. The picture is dpst.png.This might explain the numbering system for the example above where the SPDT is separated out into DPST.It can be seen that the numbers for the contacts of the first switch start with 1 and the contacts numbers for the second switch start with 2. If a contact is NC the second digits in the contact numbers are 1 and 2 and if the contact is NO the second digits are 3 and 4.

author: Cicada
author_rank: Regular Contributor
timestamp: July 31, 2021, 03:27:53 pm
content: See more info in section "Terminal marking" on page two in the attached pdf (Finder-general-technical-information-en.pdf)This section elaborates on the standards for terminal marking.It's clear that this standard (or set of standards, see below) is applicable to more than just relays and contactors. It is also applicable to the terminal numbering of timers, special function relays, and more. See the rest of the pdf.The pdf (441442.pdf) shows the correct applicable European standards. Would have loved to see these standards but I can't even find them on thehttps://www.cenelec.eu/website.So if it's difficult to buy them I suppose few people have peeked inside.
Enable pin on negative regulator - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: July 21, 2014, 06:31:33 pm
content: Hello,p/n TPS7A3301http://www.ti.com/lit/ds/symlink/tps7a3301.pdfThis regulator has a positive voltage capable enable pin but is a negative voltage regulator.What kind of fancy magic is happening in the EN circuitry? Is there a chance of the negative input rail interacting with the EN pin in the case where the EN signal is (say) at +3V but the negative input voltage is high-impedance? If there are input protection diodes on EN, it must be a zenerish thingy?I'm sure the people at TI thought about this, I just wanna know.TIA

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 21, 2014, 07:30:11 pm
content: Neato, a window comparator sort of thing.It's probably protected by a zener (avalanche) structure, yeah. Doesn't say the maximum voltage depends on supply, so it must be its own thing, no diodes.Oh, for the days when engineers wrote datasheets, and equivalent circuits were provided by all.Tim

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: July 21, 2014, 07:32:24 pm
content: I could always ask for an eval board and torture it. But that seems gauche.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: July 21, 2014, 07:56:15 pm
content: or a spice model... duh... senior moment today...

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 21, 2014, 08:04:09 pm
content: If it's not encrypted, or a simplified macro model, or...
Enabling USB 3G mdem... - Page 1
Forum section: electronics / projects

author: SL4P
author_rank: Super Contributor
timestamp: March 09, 2016, 07:59:01 am
content: As it stands, most modern USB modems - initialise as a mass-storage device, so the user can install drivers etc. And only then - toggle an internal state to expose the modem device to the OS.There is a Linux tool (usb_modeswitch) to disable/modify this function (feature?), but nothing I can see in the embedded or Windows world.As I haven't used Unix since before most of you were born, and the urgency of this project is a bit higher - I'm looking for some help in disabling this startup flag - either from Linux - an embedded platform (USB host), or in Windows.(The linux process is documented - but I have no idea where I am installing and configuring an application under Ubuntu.)Ultimately, this will become part of my project - to pre-configure the modems before they're installed in various embedded projects and delivered.I can currently see the USB device desriptors etc under my embedded platform - so the comms is in place and working - I just need to bang the mass-storage instance on the head!HELP!

author: janoc
author_rank: Super Contributor
timestamp: March 09, 2016, 08:57:35 pm
content: AFAIK, all you have to do is to mount and unmount the mass storage device in Linux. Once you unmount it, it will switch modes. The firmware likely detects the "eject media" command. At least this has worked for my 3G dongle I have got few years ago from SFR here in France.I have checked the source code for usb_modeswitch, but basically all that it does is to send the eject media message if it sees a mass-storage device. There doesn't seem to be anything in there to make the setting permanent - that may not even be possible, it depends on the firmware in the modem and whether there is any writeable storage onboard in the first place.You could probably do the same and have your target system that will be using these modems reset it and then send the eject as part of the initialization. The code starts from line 716 in usb_modeswitch.c

author: SL4P
author_rank: Super Contributor
timestamp: March 09, 2016, 09:00:46 pm
content: thanks for the info...I read a few posts that refer to 'writing' a specific string into the modem to change the default behaviour, but your info is certainly worth looking into.thanks again.
Enamelled wire manufacture - Page 1
Forum section: electronics / projects

author: akis
author_rank: Frequent Contributor
timestamp: March 21, 2017, 07:02:51 pm
content: Hello,I would like to insulate a small, flat conductor (2.5cm2) using a very durable material. For example the polyurethane used to enamel copper wires is very sturdy, and does not come off, unless you either file it, or heat it up to 400C.Polyurethane is typically sold as wood varnishing (eg yacht varnish), but when I apply it on a surface and let it dry, it is possible that it will peel off, if you pull hard enough.I presume that the manufactured enamelled copper wires although using polyurethane, they must use some other process that makes the coating really tough (and flexible).I presume if I take a clean copper wire and dip it into polyurethane and then pull it out and let it dry, it will not be the same as the industrially made enamelled copper wires.Does anyone know what the exact process of enamelling is so that I may apply it onto my flat conductor?Many thanks

author: SeanB
author_rank: Super Contributor
timestamp: March 21, 2017, 07:27:18 pm
content: Take your copper strip, clean it in solvent, then use some fine waterpaper to clean the surface of oxides, and roughen it, then wash again in solvent and dry. Then dip in the varnish and leave to dry, then bake for a few hours to harden it.enamelling is a glass coating applied and then melted to the copper, and needs some clean substrate, and a slurry of glass powder in a gum arabic suspension ( to make it a slurry) that is then fired in a reducing atmosphere ( no more oxide forming) to melt the glass into a layer on the surface.Cheaper is to use a thermosetting plastic and lower temperature in an oven, or to use an automotive epoxy paint instead, less need for high temperature, and pretty durable, plus easy to get in colours and a clear as well.Look for enamelling or powder coating for a number of parts, or just a small amount of paint from a local car paint shop for onesies.

author: calexanian
author_rank: Super Contributor
timestamp: March 21, 2017, 10:43:22 pm
content: They usually either electrolytically clean or etch the wire, or sometimes even both before coating it to give a clean surface that the coating will bond to. I like the mentioned epoxy paint approach. I would as said clean it in a good solvent then lightly burnish it with sand paper or steel wool then apply a high quality paint. Perhaps even multiple coats of spray conformal coating since you know it will have good electrical properties. I might even consider plastidip or some such thing. Glyptal paint would also be very good, but it can be hard to find.
ENC28J60 Ethernet controller intermittent startup failures - Page 1
Forum section: electronics / projects

author: joegtp
author_rank: Contributor
timestamp: February 21, 2017, 06:47:15 pm
content: 2 times out of 10 my ENC28J60 fails to startup. It's mounted on a custom PCB using Contiki's Driverhttps://github.com/contiki-os/contiki/tree/master/dev/enc28j60powered by a linear 3.3V voltage regulator. The MCU starts up find and can talk with the ENC28J60 (registers, etc) but I get no traffic in or out from Ethernet. I thought at first it might be a power rail issue but after measuring the 3.3V rail on the oscilloscope it never drops below 3.25V. My next thought was the oscillator not starting up, but probing that it looks fine as well at 25MHz. I was hoping someone might have some other troubleshooting tips to track this down.

author: Scrts
author_rank: Frequent Contributor
timestamp: February 21, 2017, 08:45:11 pm
content: Does it have a reset pin? You did not provide a link to the datasheet. Try to power it up in controlled behavior. Check when 3V3 is good (power-good pin) and then release the reset.

author: joegtp
author_rank: Contributor
timestamp: February 22, 2017, 04:53:06 pm
content: Oops sorryhttp://www.microchip.com/wwwproducts/en/en022889Just verified, I'm pulling the ~reset pin low until I start SPI communications with it. There is an errant (#2) regarding startup but the code has a 2ms sleep which should mitigate this.I just changed the code a little bit to try and send data a couple times and if that fails I hard reset the chip using the reset pin and it appears to solve the issue but this is not elegant at all since it requires an extra couple seconds to the startup process 2 out of 10 times.The more I play with it the more it appears to be an oscillator issue. I might try hooking up my o-scope to the reset pins and an oscillator pin to check the timing of oscillator startup. I'll also look up the caps I'm using on the oscillator which might be causing startup issues.

author: Scrts
author_rank: Frequent Contributor
timestamp: February 22, 2017, 08:13:43 pm
content: I've worked with this chip a little bit and hated it. It always crashed when connected to any network bigger than 3-4 clients. Point-to-point connection seemed to be OK. It's also a beast in terms of current consumption comparing to what it does...

author: joegtp
author_rank: Contributor
timestamp: February 22, 2017, 09:06:11 pm
content: Any alternatives you could recommend?

author: Scrts
author_rank: Frequent Contributor
timestamp: February 23, 2017, 01:47:13 pm
content: I've switched to STM32+Micrel PHY later on, but people around usedhttp://www.microchip.com/wwwproducts/en/en541877for small projects with success.
Enclosure (with USB) ESD and EMI approach - Page 1
Forum section: electronics / projects

author: jars121
author_rank: Regular Contributor
timestamp: January 12, 2021, 12:54:24 am
content: Hi everyone,I've been researching ESD and EMI techniques generally of late, which has highlighted that correct shielding and grounding is complex and the 'optimum' solution is dependent on the individual use case. With that said, I'm now trying to apply the concepts to my particular use case, the pertinent elements of which are as follows:Single, mixed signal PCB (high-speed, low-speed and analogue)Aluminium enclosure with apertures for I/O connectorsThe board is DC-powered (i.e. no direct mains Earth connection)The PCB uses a USB connectorI started with Henry Ott's blog post on this very topic:http://www.hottconsultants.com/questions/chassis_to_circuit_ground_connection.htmlHenry's suggestion is the following:QuoteMy first question: given that I've got high-speed signals at play, would I be best off having 2-4 connections between the circuit ground and the chassis at the various I/O areas of the board? I wouldn't be making any such connection near the analogue side of the board.My second question: how should the USB shell be treated? I've gone through a number of related threads, including the following link, which provides arguments for a range of approaches.https://www.eevblog.com/forum/projects/usb-shield-ground-connection/In the past I've used a USB Shell copper pour around the USB connector, which has then been connected to the circuit ground via either a ferrite bead or a high ohm resistor in parallel with a small capacitance capacitor. These approaches were based on manufacturer datasheets, guidelines and demonstration boards. However, I've since read dozens of posts and comments (including many in the above linked eevblog post) where people swear by direct connection of the USB shell to the circuit ground. If this direct connection is favoured, I imagine I'd also add a connection (right next to the USB connector) from the circuit ground to the chassis?
Enclosure and PCB design for sd card access - Page 1
Forum section: electronics / projects

author: cameronaps
author_rank: Newbie
timestamp: January 29, 2017, 09:27:06 am
content: Hi,I am currently trying to design an enclosure and PCB for a data logger. The problem is i need to be able to insert and remove the micro SD card through the side of the enclosure, ie. without opening the enclosure. I am a bit stuck for ideas for this issue. Any suggestions?Thanks in advance

author: DTJ
author_rank: Super Contributor
timestamp: January 29, 2017, 10:05:38 am
content: Use a SD card holder of the push-eject style, the installed card edge can sit flush or just proud of the enclosure surface.If you want it sealed against the environment then perhaps look at an enclosure with a hinged sealed lid.

author: eugenenine
author_rank: Frequent Contributor
timestamp: January 29, 2017, 08:47:20 pm
content: Something like thesehttp://www.hammondmfg.com/1593HAM.htmlittle slot for the card. Looks at the pdf for the beaglebone one as the pic shows the end opposite the sd card.
Enclosure / Connector Sourcing or Suggestions - Page 1
Forum section: electronics / projects

author: zanfar
author_rank: Contributor
timestamp: August 10, 2024, 06:07:34 pm
content: I am slowly progressing with myIsolated Variac Projectbut I am having trouble sourcing two components and I thought I would ask the hive-mind:First, the chassis. As a rough estimate, I need/want something about 14" wide, 6" tall, and at least 8" deep. Hammond has long been my go-to, but they don't make anything quite that large that I can find. My fallback is to simply contract out the sheet metal bending, but a pre-built enclosure would be preferable. This is less about "find the exact box" and more about "where haven't I looked".Second, I would like to include an external emergency stop, but given my bench is rather small, I don't want it to be permanently attached AND I don't want it to be required. Ideally, this means I would have a jack with a built-in switch so when unplugged, the estop circuit is bypassed. (There is an estop on the device itself, as well as an output disable; this would be for a tertiary switch on the end of a lead that can be placed conveniently). However, that feels unlikely, so I'm fine with constructing a jumper when unused.The key here is that I need something that locks or has a firm positive capture, and that is relatively flush with the front panel. If I have to build a jumper for the jack, I don't need 4" of connector sticking out. For example, I was considering a Neutrik PowerCon but the plug is quite long. This may be a lost cause.I've also considered simple banana jacks as jumpers are readily available and easy to manufacture, but I lose the positive lock, and I don't like similar connectors being used for dissimilar purposes on the same device, and banana jacks are already used for outputs.Currently, the front-runner are Anderson PowerPoles, but I'm curious if there is something better.Thanks!

author: Benta
author_rank: Super Contributor
timestamp: August 10, 2024, 09:10:45 pm
content: For that size, why not not go for a 19" rack solution?Plenty out there, both open frame and enclosed types.
Enclosure electronic box heating +20°C/+70°F - Page 1
Forum section: electronics / projects

author: lem0nhead
author_rank: Contributor
timestamp: December 26, 2021, 10:09:21 am
content: HiI made a simple electronic project using an ESP32 and some relays (rated for 30A) that switches 13A/230V. This is enclosed on a "project box" that's about 1 liter in volume.When the switch is on, I noticed the box get pretty hot (the temperature increases about +20°C/+70°F).The box is not completely closed since there's a non-sealed hole on the top for the wires to come in/off.Some quick calculation (first time I'm doing it though) shows that 0.2Wh is enough to heat 1L of air to +20°C, so perhaps this is normal heat from resistance of the wires/components.Does that sound reasonable? One thing that makes me not worry much is that the temperature increases quickly at first, but stabilizes (see graph below, ignore the values in the bottom, they're noise).Thanks

author: Kleinstein
author_rank: Super Contributor
timestamp: December 26, 2021, 10:20:31 am
content: The heat capacity of air is pretty low. The main part it more the heat capacity of the relay, the board and the box itself.Usually it is not so much the heat capacity, but the termal conduction to care about. So the final temperature rise and not how fast is rises.The temperatures look pretty high to start with. A 20 K temperature rise is not be big deal if it is starting at 20 C.

author: lem0nhead
author_rank: Contributor
timestamp: December 26, 2021, 11:18:11 am
content: The temperature is pretty high to start with because I'm cheating and using the ESP32 CPU temperature sensor. It rises because the surroundings get hot, not because it's doing more work (it's just keeping 2 relays on).
Enclosure for matrix board - Page 1
Forum section: electronics / projects

author: The Chump
author_rank: Contributor
timestamp: July 06, 2020, 02:27:13 pm
content: Does anyone know of any plastic enclosures that have mounting posts compatible with these standard matrix boards?https://uk.farnell.com/multicomp/mc01007/prototype-board-phenolic-72mm/dp/2768277(Also available from other suppliers/manufacturers with varying part numbers)Thanks,Alex

author: rdl
author_rank: Super Contributor
timestamp: July 06, 2020, 08:59:10 pm
content: I know of a few places that sell boards made for specific boxes, but they're all here in the US. BBP makes boards for some specific Hammond boxes. MPJA sells some cheap boards to fit some cheap boxes they sell. There are probably others. Seems like there would surely be somebody selling board/box kits on eBay or Amazon, etc.http://busboard.com/pcbhammondboxhttps://www.mpja.com/3-3_16in-X-2-1_2in-Protoboard-for-15913-BX-Box/productinfo/15914+PB/

author: The Chump
author_rank: Contributor
timestamp: July 07, 2020, 11:00:33 pm
content: Interesting, but I have these boards and am looking for a box...

author: wizard69
author_rank: Super Contributor
timestamp: July 09, 2020, 05:08:34 am
content: Quote from: The Chump on July 07, 2020, 11:00:33 pmMeasure up the board and go looking on the various box manufactures web sites. It is doubtful you will find an exact fit.

author: The Chump
author_rank: Contributor
timestamp: July 09, 2020, 09:45:07 am
content: Already exhausted myself doing that. Dimensions are provided in the datasheet from Farnell. Nothing seems to be even close.I'm posting here on the off-chance that someone else found something.

author: Boxgirl
author_rank: Newbie
timestamp: July 09, 2020, 03:04:31 pm
content: Hammond Electronics sell a wide range of Electronic enclosures. Maybe try contacting them?

author: rdl
author_rank: Super Contributor
timestamp: July 09, 2020, 05:12:00 pm
content: Personally, I'd toss the board and look for a better solution. Consider it a cheap lesson, when designing a project that will go in a box, start with the box and make everything else fit.

author: The Chump
author_rank: Contributor
timestamp: July 09, 2020, 09:08:14 pm
content: Thank you for your sage advice. Not quite what I asked for...

author: rdl
author_rank: Super Contributor
timestamp: July 09, 2020, 09:32:56 pm
content: Another possibility is the type of case where you slide the board into card guides instead of screwing it to posts. All you'd need to do is get the width reasonably close and make sure it's long enough and thick enough for the rest of your parts to fit.Similar to this kit set up.https://www.amazon.com/PR2H1-ProtoBoard-Box1-Kit-KBOX1-AC-SV-PR2H/dp/B00W865BGW/

author: themadhippy
author_rank: Super Contributor
timestamp: July 09, 2020, 09:50:46 pm
content: QuoteBuy a suitable size box and add your own mounting posts,either by drilling some holes and using nuts and bolts or if holes are a no, adhesive pillars
Enclosure Inlet- opening - Page 1
Forum section: electronics / projects

author: rakeshm55
author_rank: Regular Contributor
timestamp: May 14, 2012, 05:05:35 am
content: Hi,I am having an enclosure for a wireless gas detector. I am having an enclosure Black color , (similar to a Junction box for electrical terminators) (98x98x52mm).My wireless and sensor modules can be fiitted into the box. Inside the box I am fitting the sensor and a Buzzer alarm. As of now I am drilling holes in the junction box for inlet for gas and opening for buzzer.I would like to have grille type openings for both gas and Buzzer. How to do this ??Is there any standard fixtures (grille type seen in door alarms) available which could be mounted on the enclosure walls ??All suggestions are welcomeRegardsRakesh M

author: rakeshm55
author_rank: Regular Contributor
timestamp: May 14, 2012, 01:27:05 pm
content: Pic of the junction box with the opening for Gas inlet /audio alarm.

author: daedalus
author_rank: Regular Contributor
timestamp: May 21, 2012, 01:24:09 pm
content: You need to consider what level of ingress protection you want to achieve with the enclosure, as this will impose limits on the size of holes allowed, and whether you will need internal baffles behind the hole.The cheapest option would be to either drill one big hole, then glue a mesh window over the inside, or drill a cluster of smaller holes in the case (with cnc this will look quite professional).

author: FJV
author_rank: Regular Contributor
timestamp: May 21, 2012, 05:02:32 pm
content: Maybe use a fan guard, like those in computers.
Enclosure - letting sound out & stopping water getting in? - Page 1
Forum section: electronics / projects

author: max_torque
author_rank: Super Contributor
timestamp: May 29, 2015, 06:11:03 pm
content: A few years back i'm sure i found a company that supplies "sounder diaphragms" to enable an enclosure with an internal sounder to emit that sound but remain "sealed". However, my GoogleFoo is letting me down and i can't seem to find anything similar now!Anyone used something similar?

author: qno
author_rank: Frequent Contributor
timestamp: May 29, 2015, 06:56:02 pm
content: Maybe it did not work and they stopped production??

author: SeanB
author_rank: Super Contributor
timestamp: May 29, 2015, 07:10:40 pm
content: IP68 cabinet vent........

author: nali
author_rank: Frequent Contributor
timestamp: May 29, 2015, 07:46:44 pm
content: Quote from: max_torque on May 29, 2015, 06:11:03 pmLike these?http://www.visaton.com/en/chassis_zubehoer/koerperschall/index.htmlhttp://www.woweeone.com/#!gelaudioshop/c16rb

author: max_torque
author_rank: Super Contributor
timestamp: May 30, 2015, 10:49:45 am
content: Ah ha, bingo:http://www.gore.com/en_xx/products/venting/portable/gaw113.html?xcmp=imas_gaw113They are called "acoustic vents"
Enclosure project Mk1 - Page 1
Forum section: electronics / projects

author: PDXjason
author_rank: Contributor
timestamp: April 14, 2017, 06:56:38 pm
content: I'm making a gadget for controlling temps for my smoker and didn't really like the blah enclosures you buy OTS, so I designed a clamshell one in Sketchup and printed it at home on my 3D printer.Here's the original designhttps://drive.google.com/file/d/0BxauayekJllCZ0YtY2J0N29ybms/view?usp=sharingthe rough printhttps://drive.google.com/open?id=0BxauayekJllCZlFOY3JQcHoxTk0and the finished enclosure (I added spray stone then spraypainteded satin black over it to give it a texture).https://drive.google.com/open?id=0BxauayekJllCamN6ZF9SX1NoQ28It's certainly not exactly what I envisioned, but a little different than the OTS stuff.

author: PDXjason
author_rank: Contributor
timestamp: April 17, 2017, 04:03:53 pm
content: This is the first thread where I've added photos. Can people see these? I'm not sure what the best means is to posts photos on the forum.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 17, 2017, 05:14:47 pm
content: luckily the google drive pictures can be seen. whats wrong with the "attachments and other options" menu? btw i only want to say. give extra care to screw mounts as that is the weakest point in 3d printed enclosure, extra twist to the screw will snap that off. either you reinforce that with extra plastic during the CAD design or properly heat treated it thereafter. i will pick both.

author: PDXjason
author_rank: Contributor
timestamp: April 17, 2017, 05:42:14 pm
content: Great advice, Mechatrommer.I'm already on Mk2, and I beefed up the screw mounts because I snapped one off just by looking at it.My final prototype will be molded in silicone, and I will create resin casts of it. 3D printing takes too long.
Enclosure with battery compartment - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: March 24, 2016, 08:50:15 pm
content: I'm looking for a range of enclosures that also have a battery holder in them. So ideally a box that a hatch slides off so that the batteries can be replaced.

author: Thor-Arne
author_rank: Unknown
timestamp: March 25, 2016, 08:42:11 am
content: Something likethis?
Enclosure with infra-red window - Page 1
Forum section: electronics / projects

author: perdrix
author_rank: Frequent Contributor
timestamp: December 31, 2023, 12:37:45 pm
content: I'm looking for an enclosure. It needs to be about 180-250mm long, at least 110mm wide (need to accommodate 100mm x100mm PCB) and have sufficient depth for Speakon panel mount sockets and some 4mm binding posts. Sockets and binding posts can be at the left and right ends or on the rear (if the width is increased to at least 150mm).The catch is I want to have a window to allow IR control signals in.The Hammond 1591ETRD would work I guess as it is 191 mm x 110 mm x 61 mm, but it's not the aesthetic I'm looking for. I'd much prefer a black metal or plastic enclosure with a small IR window.Does anyone have recommendations that won't involve costly machining work?ThanksDavid

author: jpanhalt
author_rank: Super Contributor
timestamp: December 31, 2023, 12:45:58 pm
content: All plexiglass i(acrylic) transmits IR at the wavelength you will likely be using. Some boxes may come with a window made of that; otherwise, you will have to DIY. Other plastics may also work.As for the box, there are lots of suppliers besides Hammond. Which ones have you already searched?Here's a link to the transmittance curves for various clear plastics:https://www.gsoptics.com/transmission-curves/

author: Terry Bites
author_rank: Super Contributor
timestamp: December 31, 2023, 03:52:15 pm
content: Regular LED light pipes transmit IR. You can get flush mount types. With no light from inside the box the pipe will appear to be black.

author: CosteC
author_rank: Regular Contributor
timestamp: January 12, 2024, 09:07:55 am
content: https://www.tme.eu/gb/details/z-112ajf/enclosures-with-panel/kradex/z112ajf/https://www.tme.eu/gb/katalog/enclosures-with-panel_100623/?params=339:1511539,1629217_panel-colour:red,semi-transparent-redThere is whole category of enclosures with windows. Sometimes red sometimes almost black.

author: perdrix
author_rank: Frequent Contributor
timestamp: January 12, 2024, 04:27:16 pm
content: Thanks - In the end I just went with a Hammond die-cast and drilled a 4.5mm hole for the IR sensor lens (TSOP4838).CheersDavid

author: tooki
author_rank: Super Contributor
timestamp: January 12, 2024, 10:05:47 pm
content: Quote from: perdrix on January 12, 2024, 04:27:16 pmFor good performance, make sure to follow Vishay’s recommendations on window size and placement. Here are the ones for the package type (its name is “Mold”) you selected:https://www.vishay.com/en/optoelectronics/opto-window-area-calculator/mold/https://www.vishay.com/docs/82758/windowsizemold.pdf
Enclosures with multimeter selection switches? - Page 1
Forum section: electronics / projects

author: rea5245
author_rank: Frequent Contributor
timestamp: June 08, 2019, 08:45:43 pm
content: Handheld multimeters have those distinctive rotary selection switches. I've been thinking of making a gadget that uses that kind of switch. It requires a PCB with circular traces, which might be tedious to lay out but is otherwise no big deal. The challenging part is the mechanics. I can't find any source of handheld enclosures with those selection switches.Does anyone know of a source? Alternatively, can anyone speculate on why there isn't one? It's such a common UI for multimeters, I'm surprised there's no desire to use it elsewhere.- Bob

author: ataradov
author_rank: Super Contributor
timestamp: June 08, 2019, 09:07:56 pm
content: Standard case manufacturers are generally not good at coming up with a variety of case designs. No idea why.In this case it may be hard to come up with a universally useful case, since the number of positions would be fixed, and may not match the needs of a lot of projects.You best bet may be to buy those cheapo meters and reuse the case if it otherwise fits. They cost cheaper than simple plastic project boxes anyway.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: June 09, 2019, 01:13:15 am
content: When a rotary switch is designed into a product like the multimeter switches you are referring to, it means that all the parts have to be designed to work together. How should a standard enclosure implement this?Various parameters, like the stiffness of the PCB, the makeup of the slider, the required contact force and the characteristics of the various spring elements have to be considered. The position count and contact size will determine the necessary precision, which has to be balanced against ease of action. Those go into the design of the detent mechanism, as the force to leave a switch position should not be too high and involuntary 'overswitch' avoided.A high contact force gives good contact but results in high contact wear - leading to early failure except when special surface materials are used.Having an enclosure with a recess for a large knob is nearly an afterthought here. And into the enclosure design there are other inputs too, like position of the jacks, fuse and battery access, isolation barriers.Given, the cheap multimeters look all very similar. So by testing some of the abovementioned characteristics empirically, you could reuse such components. But to make it work right? I did not try.For low-volume, I would rather separate the Switch from the PCB. For that, there are solutions in the form of good rotary switches.

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 09, 2019, 01:36:23 am
content: If you're only making a few, you can 3D print the mechanism. If you use capacitive or optical sensing, you can eliminate the need for physical contact and eliminate the contact wear problem. Or put a few detents on the edge of the knob that push on switches.Of course, rotary encoders are another choice.