hybridfree/eevblog-posts huggingface dataset:
Using Freecad to specify cut-outs on enclosure - Page 1
Forum section: electronics / general

author: 741
author_rank: Frequent Contributor
timestamp: September 27, 2022, 04:16:45 pm
content: I'd like to understand something about specifying slots milled into a commercial enclosure (I use Kicad as the EDA side, and the PCB was genertaed via the KicadStepUp workbench).My contact (at the PCB assembler) uses another company for this. I've been told that 2D PDF or preferably DXF/DWG can be used.I don't know how (or if) this relates to the Freecad Path Workbench - but maybe I don't need 'gcodes' etc for simple '2D' slots through a surface?One thing that seems clear is I'd have to specify a datum point.The accompanying image shows where I'm up to - I still have to define some 'pockets' thugh the aluminium enclosure. For instance, there could be a rounded rectangular aperture to accomodate the 6-way header.

author: hubi
author_rank: Regular Contributor
timestamp: September 27, 2022, 08:41:13 pm
content: I don't think you have to worry about generating GCODE, that's pretty specific to the machine and tooling used for milling and will be done by the machine shop.You can use librecad or inkscape to do a sanity check on the export generated by FreeCAD. If the DXF looks right in librecad or inkscape and has the right size, you're probably fine. It's also quick to make a dimensioned drawing in the TechDraw workbench and send that along for good measure.

author: beanflying
author_rank: Super Contributor
timestamp: September 28, 2022, 05:01:56 am
content: Just one issue that will come up is your model shown above is an STL type and it and most GCode/CAD formats will not play well with it when it comes to generating CAM toolpaths. So assuming this is the native format for that part of your model you might need to start there and remodel it.
Injection Mold Design:  Ribs:  too thin at top, too fat at bottom. - Page 1
Forum section: electronics / general

author: frogblender
author_rank: Regular Contributor
timestamp: September 20, 2022, 08:18:35 pm
content: Behold a plastic cover, about 50mm tall. The taper angles are 1° per side (2° total).Alas, the top of the ribs are skinny (~1mm), but the bottom of the ribs are too fat (2.8mm)... which will cause sink marks on the cosmetic face (in the picture, you can't see the cosmetic face because it is on the bottom).This problem applies to all the ribs.How to fix?

author: Brumby
author_rank: Unknown
timestamp: September 22, 2022, 11:56:06 pm
content: 1mm to 2.8mm over 50mm works out to be exactly right with a 1 degree taper, since that taper is on both sides.What do you want for these dimensions?

author: frogblender
author_rank: Regular Contributor
timestamp: September 23, 2022, 12:20:11 am
content: Quote from: Brumby on September 22, 2022, 11:56:06 pmI want 1mm at the top, 1.5mm at the bottom, and 1° over the 50mm. Which is obviously impossible, as your calculation have confirmed.So I want to know what somebody with experience with injection mold designs would do.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 23, 2022, 06:13:19 pm
content: Disclaimer, I don't have experience with molding. But I have seen parts like this, which simply sink in the opposite side to balance the mass (and I guess save a little material). If you need the opposite face flat, and can't, like, notch the side either, maybe just settle for the shrinkage? Also, maybe it can be sprued closer to that, or multiple sprues, or something.Tim

author: tszaboo
author_rank: Super Contributor
timestamp: September 23, 2022, 07:59:04 pm
content: Quote from: frogblender on September 20, 2022, 08:18:35 pmI've managed designers who were contracted for injection moldings. Housings and such.In my experience there are many things that you need to apply when designing these. The end result can have all kinds of bad looking warpage, surface finish issues and simply impossible to do designs. I know this is mechanical design, which is clearly* not real science, unlike electronics design... but just maybe, it is best to hire an expert for a few hours, when making a tool that costs thousands of dollars.*even electroboom said that doctors are just plumbers.

author: mc172
author_rank: Frequent Contributor
timestamp: September 26, 2022, 11:10:28 pm
content: You probably don't need a whole degree of draft which will help you somewhat. Can you upload, or send me privately, a STEP/IGES file?
DIY SMT Tape and Reel Packaging Machine? Anyone Know?  - Page 1
Forum section: electronics / general

author: KG7AMV
author_rank: Frequent Contributor
timestamp: September 08, 2022, 11:17:02 am
content: Anyone have plans for a DIY SMT Tape and Reel Packaging Machine?Don't care if its a hand crank manual but must be able to seal the hot seal cover tape to the carrier.Want to avoid PSA cover tape is 5X's the cost.

author: bomp
author_rank: Newbie
timestamp: October 02, 2022, 08:19:51 am
content: Don't know where to get this tape. sorrybomp

author: Infraviolet
author_rank: Super Contributor
timestamp: October 02, 2022, 10:12:17 pm
content: There's a guy on youtube building an open source P and P machine with feeders which peel OFF the tapefrom SMD reels, maybe you could make something like it to run in reverse and attach some sort of glue in tiny quantities as it runs?
Keithley 2450- 2470 and Labview - Page 1
Forum section: electronics / general

author: nmtriplett
author_rank: Newbie
timestamp: August 06, 2022, 01:15:45 am
content: Hi all, I was led here with internet search on Keithley models with different trigger edges and it seems like there are folks here who know their stuff.I am trying to integrate a very simple Keithley trigger model in Labview with an oscilliscope portion that is already set to receive waveform and save. All I want is for Keithley to source X voltage and Y current once a pulse is detected on digital IO #1 and enable output for 500ms and save in default buffer. With Labview, seems the easiest way to do this is with SCIP commands, but for some reason scope is triggering before output is enabled. Thoughts? I can send Keithley log and what the trigger model looks like.Related, I have heard TSP code is much more powerful for Keithley than SCPI and have also seen the thread on running a Labview "wrapper" VI that runs the TSP code. Would you recommend this over SCPI and suggestions on creating trigger model for above scenario in TSP?Thanks in advance for any help!
non reactive paint for silver? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: November 27, 2022, 06:03:08 am
content: I have some silver plated objects I want to paint. Its a very thin silver plating.I thought spray paint would be good, but I am wondering if it can effect the silver plating with the extra stuff in the paint (i.e. rustoleum has corrosion chemistry stuff in it).should I just use sheet rock paint?Like self etching primer seems like a bad idea. But regular primer?

author: Nominal Animal
author_rank: Super Contributor
timestamp: November 27, 2022, 11:26:32 pm
content: How about acrylic paints, specifically hobby and model paints? Possibly with a non-etching primer?Silver itself is quite non-reactive. The etching is what you want to avoid, so I guess "non-etching" is a keyword to use.There are model car paints that really have the same look and feel as automotive paints, but you should verify they're okay to use on metals as well as plastics; the primer is likely different for the two. (Lots of people restore old metal toys, so hobby people are likely to know about this stuff. Just mention the silver is plated, no need to mention electronics.) I'd specifically look at the acrylic ones.Oh, and if you want to protect whatever is under the paint, consider using a lacquer layer. (Exactly what kind would be good for a plated surface, I don't know, but hobby paint people do; they used to use that kind of stuff a lot when they still made toys out of metal, and they're quite expensive and often restored today.)

author: coppercone2
author_rank: Super Contributor
timestamp: November 27, 2022, 11:51:40 pm
content: yeah transformer varnish makes sense I guess

author: coppercone2
author_rank: Super Contributor
timestamp: November 28, 2022, 05:33:36 pm
content: I put regular non etching primer and then liquid electrical tape on it. Nice coating so far.

author: bidrohini
author_rank: Regular Contributor
timestamp: December 15, 2022, 05:57:33 am
content: Maybe you can check this:https://ro.pinterest.com/pin/360850988874427828/
Keithley 2450 / 2470 SMU change trigger edge inside a trigger model? TRS - Page 1
Forum section: electronics / general

author: slow_rider
author_rank: Regular Contributor
timestamp: July 12, 2022, 05:04:53 pm
content: So basically I want to be able and trigger on both edges.At the top of the file I have this code to trigger on digital in 1, rising edge:Code:digio.line.mode = digio.MODE_TRIGGER_INtrigger.digin.edge = trigger.EDGE_RISINGBut it seems that if I insert a similar line to #2 with EDGE_FALLING inside the trigger model it does not do anything.Anyone knows how should I do this?

author: thm_w
author_rank: Super Contributor
timestamp: July 12, 2022, 09:17:27 pm
content: https://www.manualslib.com/manual/1322979/Keithley-2450.html?page=702Quote
Z axis diving with THC150 and mach3 - Page 1
Forum section: electronics / general

author: lamoule74
author_rank: Contributor
timestamp: June 08, 2022, 07:01:45 pm
content: Hey there,I'm not sure this is the right forum to talk about this but who knows if anyone know Mach3I'm on my way to finish a CNC plasma cutter with a boilermaker.We are using Mach3 R3.043.066 is used to control the CNC and we are using a THC150 (proma) for the height control.When launching the job, the Z axis got a problem: it diving linearly until touching the plate.On Mach3, when we launch the job we can visulizing the heigh constant, then at the end we observe the Z value decremented at once.It is like the Z motor needs to be calibrate or corrected by an offset, something like this...The fact is it work on manual mode.Is anybody recognize this issue?Do you have any idea what's happening could happening ?Please let me now if you can help me.Cheers.

author: thm_w
author_rank: Super Contributor
timestamp: June 08, 2022, 10:25:34 pm
content: Is there some homing Gcode in there that is sending the Z axis down possibly? Since it works in manual mode.Should be fairly obvious if the relays are clicking on for Z up or Z downhttps://eagleplasma.net/product/proma-thc-150/Probably better forum to ask on is cnczone

author: lamoule74
author_rank: Contributor
timestamp: June 13, 2022, 01:08:02 pm
content: Yep.I sent a message in a bottle... Like Sting would say
Looking for IR codes of Robomow RM series lawnmower remote - Page 1
Forum section: electronics / general

author: martonmiklos
author_rank: Contributor
timestamp: September 23, 2021, 08:16:59 pm
content: Hi all,I would like to control my RM-510 with an external controller. The debug port does not exposes ability to drive the motor, however there was an infra red transmitter for this device (what I do not have). I would like to simulate the codes sent by this remote. However it is no longer available, and at the end of the day I do not really need it.It's partnumber is MRK5004B:https://www.amazon.de/-/en/Robomow-MRK5004B-IR-Remote-Control/dp/B007HMLDBOIf anyone would have such a transmitter and could somehow digitize the IR codes (LIRC or any other IR signal recorder) that would be awesome.

author: martonmiklos
author_rank: Contributor
timestamp: May 19, 2022, 08:49:10 pm
content: Just for the posterity.I managed to get the firmware of the mower itself, reverse engineered it and came up with an emulator:https://github.com/martonmiklos/robomow_rm_ir_remote_emulator
What is this component? - Page 1
Forum section: electronics / general

author: luiHS
author_rank: Frequent Contributor
timestamp: April 29, 2022, 11:57:26 am
content: It was attached on the coil of an electromagnet. I have discovered it when removing the seal of adhesive tape from the coil, to measure the thickness of the cable and the number of turns.This component is connected in serial with the coil. I suspect that it may be a thermistor or a varistor, which reduces electrical consumption when the coil overheats.The coil connects to 50v and has a resistance of 4.9 ohms. So I suppose that it will have an initial consumption peak of 10 Amps, it will heat up quickly, this thermistor (or varistor) will act, increasing its resistance and reducing electrical consumption to prevent the coil from overheating, that will also reduce the electromagnetic force.This protection could also be mainly to protect the power supply, reducing the electrical consumption after the initial peak of 10 Amps.

author: Kean
author_rank: Unknown
timestamp: April 29, 2022, 12:08:05 pm
content: It is a PEPI FC-P2D thermal protection switchhttp://pepiusa.info/model-fc-p2d/

author: luiHS
author_rank: Frequent Contributor
timestamp: April 29, 2022, 01:28:27 pm
content: Quote from: Kean on April 29, 2022, 12:08:05 pmOk, if it is a simple thermal switch, it only prevents the coil from burning, it does not reduce the electrical consumption to protect the power supply as well.I think I'll replace it with PWM control for better power control and protection.

author: Zero999
author_rank: Super Contributor
timestamp: April 29, 2022, 02:58:05 pm
content: Quote from: luiHS on April 29, 2022, 01:28:27 pmThat's a bad idea. It's also there for protection against fire.If you want to control the power with PWM, then fine, but keep the thermal protection switch in place, in case your controller fails normally on.

author: Kean
author_rank: Unknown
timestamp: April 30, 2022, 02:41:21 pm
content: Quote from: Zero999 on April 29, 2022, 02:58:05 pm100% correct!It is self resetting unlike cheaper thermal fuses. Absolutely no reason to remove this unless faulty (unlikely), in which case replace it with the same or an equivalent rated part.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 08, 2022, 03:00:14 pm
content: Quote from: luiHS on April 29, 2022, 11:57:26 amIndeed.It's common to push high currents through electromagnets, but with a low duty cycle, and if for any reason the source is not turned off and this current continues for too long, the least damage will be a completely destroyed electromagnet because of the overheating.This is not only common with electromagnets, but also with other devices containing electromagnets such as industrial servo motors. They can usually be overloaded by a factor of two to 5 for short durations, for example during acceleration.
custom bump guards on stuff like HP equipment? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: May 05, 2022, 04:21:45 pm
content: I want to make some rubber? bump guards and a handle/tilt stand cover for equipment, that needs to be durable enough to withstand working as tilt stand but also soft enough to make a good grip. Like the thick guards that come on HP equipment.Not sure if there a castable resin system that can make the kinds of parts I want. Has anyone had success making this ? Things like 2 part silicone resin are too soft and plastidip is too weak. I was thinking like 3/8 thick parts. Unless you can just pour plastidip in a mold, but I suspect that will be warped garbage. Multimeter covers seem to be what I want to make essentially.

author: thm_w
author_rank: Super Contributor
timestamp: May 05, 2022, 08:56:36 pm
content: 3D printed TPU is an option.Its quite a bit stiffer than a multimeter case though, the stuff I have is 95A. I know you can get down to 85A, maybe less, haven't tried that though.

author: coppercone2
author_rank: Super Contributor
timestamp: May 06, 2022, 03:03:42 pm
content: I see a 85A resin for resin printer. When I meant castable resin I assumed I would have to make a mold, but if you can 3d print this stuff that is fine too, since I have a resin printer and I only want these things on the corners. It should still stand on the rubber feet but protect the box edges.So you think 85A is the correct number?https://wanhao.store/products/3d-printing-resin-rubber-resin-1000ml-bottlehttps://www.amazon.com/ELEGOO-Water-Washable-Printer-Rapid/dp/B081YSG83N?th=1

author: thm_w
author_rank: Super Contributor
timestamp: May 06, 2022, 09:11:19 pm
content: I don't think 85A is the correct number, just that it is easily available in TPU filament.Multimeter case might be in the 40-60A range?https://www.smooth-on.com/page/durometer-shore-hardness-scale/
Cheap PMDC servo controller - Page 1
Forum section: electronics / general

author: ezalys
author_rank: Frequent Contributor
timestamp: April 30, 2022, 05:32:54 pm
content: Does anyone have a favorite PMDC servo controller with 24V/3A capability? There's the geckodrive G320X, some older maxon controllers, the granite ioni. Anyone have any preferences? If I could find something around 50-70 USD or so I'd be pretty happy.

author: Benta
author_rank: Super Contributor
timestamp: April 30, 2022, 10:05:31 pm
content: Do you need just speed control or also position control?

author: Doctorandus_P
author_rank: Super Contributor
timestamp: April 30, 2022, 10:10:01 pm
content: Maybe one of those motors with built in controllers are interesting for you.Prices for the combo start at around EUR 100.I think JMC started with those, but I think I've seen other brands on 'Ali too.Some of them are closed loop steppers, so read the specs carefully.

author: H.O
author_rank: Frequent Contributor
timestamp: May 01, 2022, 07:17:03 am
content: Since you mention G320X, is step/direction what you want or what type of control interface do you prefer?And since you mention the Ioni I take it you're with boards without enclosure?Polulo offers a series of drives/controllers but none of them seems to offer step/direction:https://www.pololu.com/category/10/brushed-dc-motor-controllersI've worked with both the Maxon EPOS and ESCON series as well as with Granite Devices Ioni and they are allexcellentproducts but they won't hit the $75 mark.The DG4S-08020 from CNC Drive cost €99, I have not used it but have used an older drive of theirs.
Can you anneal die cast aluminium without causing distortion? - Page 1
Forum section: electronics / general

author: e100
author_rank: Frequent Contributor
timestamp: April 23, 2022, 03:35:16 am
content: I'm thinking of the die cast aluminium boxes typically sold for use as project boxes.The goal is to make the metal less brittle so that it behaves like the extruded aluminium sections you get from a hardware store.I could do the experiment myself but don't want to risk ending up with a box where the lid doesn't fit properly.

author: andy3055
author_rank: Super Contributor
timestamp: April 23, 2022, 04:08:04 am
content: It might be the chemical composition that is responsible for that. Annealing is mostly done to soften a hardened material like steel. I don't believe there is a standard composition for cast Aluminum boxes to begin with.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 23, 2022, 04:12:33 am
content: No, it's the alloy (and the casting, to some extent). They'll be something like A320 or A356, silicon based alloy. Depending on how it's cast (high pressure injection?), there may be gas inclusions as well (which makes it notoriously hard to weld..).Silicon alloys are strong in part by the usual additions (Cu, Mg, Si, etc.), but also by the excess silicon precipitating as crystals in the metal matrix. Which, being rather hard and strong, tend to frustrate the metal pushing and sliding around -- it's strengthened, harder, but also less ductile.Which for a casting, is a good thing. You can't forge or roll or draw it, it's gotta be net shape. So it's not a big deal that it's not very ductile.Unless you want to do something very different with it, which... will be a bit of a problem.So, consider some kind of cutting and bonding process instead. If you have to start with the diecast box*, cut whatever openings you need, and, say, bolt, rivet or epoxy your widgets to it.*Since the alternative would probably be something like a sheet metal box, seam welded to get the same sealed box. Which... ain't gonna be cheap.The other way is, if you can find deep-draw boxes. I don't recall running across these at the usual suspects, but maybe there's something out there. You'll only have five sides not six, like the diecast box, gotta have some kind of flange, seal and lid. But as you can guess from the method, it's wrought alloy. Now, again, it'salready been wrought,it's not dead soft, it might not bend very far -- you're lucky to bend a 6061-T6 plate past 90 degrees -- so if you want to cut open a flap or something, fire may be needed (get it somewhere around "black hot", 400-500C something like that*, this will anneal the alloy).*Typical test is to use a sooty flame to blacken it, then heat until it burns off.Tim

author: Benta
author_rank: Super Contributor
timestamp: April 23, 2022, 08:13:49 pm
content: What Tim said.The generic material name for those cast enclosures is "Silumin", and no, you can't anneal it.
JUKI KE-760 training person needed - Page 1
Forum section: electronics / general

author: jojoLED
author_rank: Newbie
timestamp: April 27, 2022, 04:03:22 am
content: Hi, bought used older yet good machine JUKI KE 760L, and some details of how it should be used, programmed, etc are not very clear to me from manuals, ideally I am looking for a training person (paid service), I dont want to spend 4weeks with slow try-and-see , rather I would like somebody to teach me to the best practises, with steapest learning curve.for example (mainly the PWB editing settings questions now):- What is and how is used BOC mark- how is used the centering PIN?- What is "Hole reference" and how to use it?- are the PWB coordinates (PWB offset, circuit layout offset) referencning always to machine 0, or to (PCB) Circuit fiducials- How to measure the Height of pick?manually seems to me very odd.- How to assemble Multiple (matrix) PCB with outer dimension 250x12mm mounted on LARGE PANEL 510x250mm (beyond machine assembly limits) in 2stages - first half, second half of set of PCBs?...The manuals I have with it are not very complex in terms of explanation and how to use it.Thank you for any inputs.
Measure power of an electromagnet - Page 1
Forum section: electronics / general

author: luiHS
author_rank: Frequent Contributor
timestamp: April 25, 2022, 02:30:53 am
content: hello.How could I know the magnetic power of an electromagnet?I know the supply voltage, which is 50v, I can measure the consumption in Amps and the resistance of the coil, but what really interests me is the power of the magnetic field it generates.It is a round electromagnet to hold metal objects.

author: eugene
author_rank: Frequent Contributor
timestamp: April 25, 2022, 06:47:29 pm
content: By "power" do you mean the force that a magnet exerts on a nearby magnet or hunk of iron?Besides building the thing and then measuring what you have, some predictions can be made with finite element analysis (FEA.)FEMMis free to download and is not too hard to learn. The downside of FEMM is that it can model only 2D systems, not 3D. But if there is enough symmetry to express your system in 2D, in either Cartesian or cylindrical coordinates, then it is not outside the realm of ordinary people like us to model.

author: anda3243
author_rank: Contributor
timestamp: April 26, 2022, 02:08:38 pm
content: I have many time successfully designed a magnetic system using this free software.https://www.femm.info/wiki/HomePageIt has some Windows95 vibes, but is easy to learn. I have successfully designed some special solenoids and had this SW present the force in N. For sure there is always some difference between simulation and reality, but it is a good start before committing to prototypes and real life tests.Some magnet and hall-sensor plots I made recently

author: Doctorandus_P
author_rank: Super Contributor
timestamp: April 26, 2022, 10:52:01 pm
content: You can buy simple ceramic or other permanent magnets, and these do not need electricity to work.In any electromagnet all consumed power (exept for the initial switch-on) is converted to heat by the ohmic resistance of the wire used.It roughly means that if you double the wire diameter (quadruple circumverence) and then als use 4 times as many windings, the total resistance, and therefore the power consumption of the magnet stays the same, while the magnet is 16x bigger and the generated magnetic field is 4x stronger.Holding force is also influenced a great deal by any gap between the electromagnet and whatever it is holding. Even a 0.1mm gap has a dramatic effect.

author: TimFox
author_rank: Super Contributor
timestamp: April 26, 2022, 11:03:20 pm
content: If you have a fixed space for the copper wire, and a fixed fraction of that space occupied by copper (not including air and insulation), then changing the wire size and corresponding number of turns will not affect the power consumed by the electromagnet at a given field strength. More turns of smaller wire will need a higher voltage at lower input current to achieve the same number of ampere-turns and require the same power.
Do single phase induction motors have a preferred stopping position? - Page 1
Forum section: electronics / general

author: e100
author_rank: Frequent Contributor
timestamp: April 24, 2022, 05:30:23 am
content: As in you cut the power and wait for it to stop. Is the rotor likely to end up in a particular angular orientation or is the final resting position totally random?

author: xavier60
author_rank: Super Contributor
timestamp: April 24, 2022, 08:54:41 am
content: I'd say random, assuming there is no stator current flow. Except maybe for some mechanical reason such as rotor imbalance.

author: Ian.M
author_rank: Super Contributor
timestamp: April 24, 2022, 10:02:49 am
content: It would depend on the type of motor. Assuming we are discussing the common squirrel cage motor, its possible that residual magnetization could affect the stopping position as there's typically enough for the motor to self-excite if spun up as a generator with a resonant load but IMHO its rather unlikely as there are several design factors that are often used to minimize cogging when running that would also do so when stopped, including skewed bars, and a preference for a rotor with an odd number of slots, which as the number of poles is always even, prevents more than one bar crossing a pole edge at the same time.

author: bsdphk
author_rank: Regular Contributor
timestamp: April 24, 2022, 05:53:16 pm
content: There is usual some residual magnetization and that will give the motor one or more weakly preferred positions.

author: bdunham7
author_rank: Super Contributor
timestamp: April 24, 2022, 06:15:11 pm
content: It's hard to generalize forallsuch motors, but if you take a standard design bench grinder with good ball bearings, you can spin the wheels by hand and readily observe that they rotate completely smoothly with absolutely no cogging. Any preference that is observable for a stopping position seems to be due to very small weight imbalances. In my experience, this all holds true for single and three phase induction motors.
Mounting MEMS microphone in housing - sealing gasket, adhesive - Page 1
Forum section: electronics / general

author: davegravy
author_rank: Regular Contributor
timestamp: April 17, 2022, 06:07:15 am
content: I'm getting my feet wet with MEMS microphones for a personal project and eventually will want to integrate the sensor into a device housing.A gasket needs to be used between the sound port and the housing. The gasket material and geometry chosen has a significant affect on the acoustic performance since it forms part of the acoustic channel with the housing, and my project is sensitive to this.I'm looking for advice on how can one practically prototype the sensor-housing interface.Are there vendors of miniature gaskets that will do small volume orders at reasonable prices? I think I'll be looking for something that's roughly 0.6mm inner diameter, 2mm outer diameter, and less than 0.5mm thick.I presume some form of adhesive is also typically used to keep the sensor, gasket, and housing bonded together. Any suggestions on what type?

author: Kean
author_rank: Unknown
timestamp: April 17, 2022, 10:55:33 am
content: Maybe you can just use a small o-ring inserted into a recess in the adjacent housing?Edit: You can find kits of mini o-rings intended for waterproof watches on eBay quite cheaply, and run some tests.

author: BreakingOhmsLaw
author_rank: Frequent Contributor
timestamp: April 17, 2022, 08:12:47 pm
content: Read the application note and the general application notes very carefully. I assume you are using ST or Knowles, they both have a lot of literature available on the subject. A big trap is the design of your accousting aperture. There's a nasty thing called Helmholtz resonance that can ruin your day.Accoustic calibrators like the venerable Bruel & Kjaer 4231 are really useful - if not indispensable - when designing anything that is remotely precise.

author: Benta
author_rank: Super Contributor
timestamp: April 17, 2022, 08:30:00 pm
content: Quote from: Kean on April 17, 2022, 10:55:33 amI second this. O-rings are standard, cheap, easy to source and available in different grades.Don't reinvent the wheel.

author: davegravy
author_rank: Regular Contributor
timestamp: April 17, 2022, 08:38:49 pm
content: Quote from: BreakingOhmsLaw on April 17, 2022, 08:12:47 pmI will be exploring different aperature designs, and impact on freq response with COMSOL but I'm uncertain about feasibility of prototyping and testing these designs without a big budget (which I assume is needed for things like custom cut gaskets).
printing on glass - Page 1
Forum section: electronics / general

author: strawberry
author_rank: Super Contributor
timestamp: January 11, 2022, 04:16:03 am
content: print size 700x127mmnot expensive silkscreen printing inks? epoxy?photosensitive emulsions?small amounts for storage

author: Martin Miranda
author_rank: Regular Contributor
timestamp: January 11, 2022, 04:38:50 am
content: ask your local sign shop if they have a flat bed UV (ultraviolet) printer. the one that used on souvenirs mugs pens...the UV printer can print a backlayer (white/black) and top clear coat.

author: strawberry
author_rank: Super Contributor
timestamp: January 11, 2022, 04:56:10 am
content: opposite side of glassback layer will block printI think they dont have that large printers

author: SilverSolder
author_rank: Super Contributor
timestamp: January 11, 2022, 05:23:49 am
content: Vinyl decals could be cut to that size, would be very cost effective.

author: strawberry
author_rank: Super Contributor
timestamp: January 11, 2022, 09:08:12 am
content: something like this

author: Martin Miranda
author_rank: Regular Contributor
timestamp: January 11, 2022, 01:08:10 pm
content: that can be done using UV printer. as it can print white ink. i'll look for it. it's silkscreen quality btw.

author: Martin Miranda
author_rank: Regular Contributor
timestamp: January 11, 2022, 01:09:33 pm
content: Quote from: strawberry on January 11, 2022, 04:56:10 amthey can directly print on t-shirts afaik. or as big as few feet. you can youtube uv printer flatbed.

author: rpiloverbd
author_rank: Regular Contributor
timestamp: February 22, 2022, 10:54:37 am
content: Depends on your application and budget. There are many options from digital uv printing to screen printing.

author: Domagoj T
author_rank: Frequent Contributor
timestamp: April 07, 2022, 09:21:41 am
content: I did something similar, but on acrylic. I wanted white background with black markings, so I painted entire back side white, then laser engraved the design (and cut the cutouts I wanted), then I filled in the engraved parts with black paint. From the front it looks quite nice if I may say so myself.Should you go this way, you may have trouble cutting glass, but the laser will burn away the paint just as well.
Keithley DMM7510 - Synchronizing TSP & Python codes - Page 1
Forum section: electronics / general

author: Coolboy4999
author_rank: Newbie
timestamp: July 05, 2022, 08:59:24 am
content: Hello.I'm working on getting a DMM7510 to work through Python code, which implements TSP commands with py_visa/py_visa_py libs.The best way I've found to send TSP commands is with a "loadscript X (...) endscript" approach, with the "my_instrumet.write()" function calls.However, Python just runs separately from TSP after sending the commands and the only way I've found to retrieve data/values from the DMM is through Python also with code such as:Code:my_instrument.write("print(tostring(tsp_value_to_return))")value_in_py = my_instrument.read()So, my questions here are:Is there another way to get information from the DMM beyond the Python/TSPwrite("print(...)") & readfunctions?If there is how could I get my Python code to check if a script has finished running in the DMM?What is the difference betweenstatus.standard.enableandstatus.request_enableand how do they work? How can I check that something is ready to be read in the Output Queue?Thanks for the attention.
copper plating lead free nickel bearing solder? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: February 25, 2022, 11:01:43 pm
content: I got a plating pen and made a plating solution with H2SO4/CuSO4/HCl and tarn-x (thiourea)it works for writing on nickel silver sheet (18 percent nickel, 62 percent copper, 20 percent zinc) and also on leaded solder, quite nicely. I get a deposit of real nice shiny copper on a eutectic solder blob.However I was trying to copper plate a nickel bearing (bridge-it, harris brand) solder joint between two pieces of copper and its just turning black.https://www.harrisproductsgroup.com/en/Products/Alloys/Soldering/Lead-Free-Solders/Bridgit.aspxis it the antimony in the solder or something thats preventing it from working? I don't think its the nickel because it works just fine on nickel silver and on leaded solder soldered to nickel silver sheet.What am I missing? I did the same procedure for both work pieces, and tried fresh plating pen tips. I think its something about the metal composition thats screwing with it. Antimony stands out at me. I don't think its a problem relating to cleaning because I hardly did anything to the sample that worked, wiped the flux off with alcohol a little bit

author: coppercone2
author_rank: Super Contributor
timestamp: February 26, 2022, 05:13:25 am
content: Ok I managed to plate one of them there are a few tricks1) put the felt or whatever it is pen into into the solution of electrolyte and pull a vacuum on it for a while to infuse it2) get a syringe of electrolyteSo its a little like tig welding, when its a big surface you can drip the syringe on the felt periodically while making a stirring motion to get the plating to attach. I don't know why this is but it worked, maybe its getting depleted by the solder or it was doing some kind of chemical cleaning and getting depleted (maybe more HCl is required). I am tempted to hook up a pump to it to turn it into a "mig" process, perhaps it would help if the tip spun as well at slow speed. It needs a vacuum collector too to that can be stuck to the surface to collect drip, its paper towel heavy... but as usual its highly non linear so controlling the drip location with a external syringe a-la tig/acetylene is best, and I am pretty sure a tip heater would help as well.Very finicky procedure
Stepper motor controllers, general use? - Page 1
Forum section: electronics / general

author: cdev
author_rank: Super Contributor
timestamp: January 25, 2022, 09:43:25 pm
content: I want to learn a bit about motor control ad want to buyseveral motor controllers for general use to use with my raspberry pi or perhaps other stuff and I want to get some inexpensive motor control board. My first project I think will be some kind of antenna rotator or az-el mount.. Bluntly, I am a rank beginner. Hoping to just learn the basics of moving stuff with motors. Very simple control of motion.Another project I'd like to tackle eventually is motorizing my ( drilling) x-y table for drilling holes in PCBs in a neater manner.I am on a tight budget though.So I want to buy at least two motor control boards on ebay that I can use to move stuff. And perhaps standardize on. I have no idea which one(s) to buy. I have a couple of four wired steppers that I have removed from old hardware, and a couple of other old unused devices that contain steppers I'd like to fool around with, a printer and fax machine..but the control board(s) that I get first I hope will be ones that I can use to interface to a wide variety of small motors as a learning platform, not spending much on them at all.Where would you start to do this?

author: thm_w
author_rank: Super Contributor
timestamp: January 28, 2022, 10:55:37 pm
content: Get some A4988 modules, they are super cheap.https://whatibroke.com/2019/08/10/a4988-stepper-motor-raspberrypi/You can directly hook them up to the pi, but, I think just buying a 3D printer type board and running GRBL on it would be easier.Example, don't know if its any good:https://www.aliexpress.com/item/1005003511625068.html

author: nctnico
author_rank: Super Contributor
timestamp: January 29, 2022, 01:07:21 am
content: Be sure to get a positional encoder as well. Stepper motors may miss steps under varying load.

author: rpiloverbd
author_rank: Regular Contributor
timestamp: February 01, 2022, 12:43:30 pm
content: If you want to control DC motors, I suggest L293D dual DC motor driver. This is the simplest type of motor controller that I've ever come across.https://www.etechnophiles.com/l293d-motor-driver-module-ic-datasheet-pinouts/There is another L293D based motor shield. This one can control DC, stepper and servo:https://kuongshun.com/products/l293d-motor-driver-boardYou can also control DC motors using Labview. Here is a tutorial if you are interested:https://www.theengineeringprojects.com/2020/12/dc-motor-control-using-myrio.html
Encoder mounting on this sort of short motor backshaft? - Page 1
Forum section: electronics / general

author: Infraviolet
author_rank: Super Contributor
timestamp: January 03, 2022, 05:25:02 pm
content: https://m.media-amazon.com/images/I/51LQC3TLA4L._AC_SL1001_.jpgThat is a type of motor with a very short backshaft and a big gearbox. Encoding from the backshaft would let you get a lot more precision than putting an encoder on the main output shaft. And there is a bit of backshaft exposed, but it is very short, barely comes a mm above the surface of the white plastic. Any suggestions on how I might fit either a magnetic encoder disc to that stubby backshaft, or otherwise find a way to use some other form of QUADRATURE* encoding from it?Thanks*I know one can count voltage spikes on the casing from brush sparks, but these don't tell direction the way quadrature does, and in some applications I've had a very nasty time trying to keep counts when I can't be entirely confident in direction.

author: thm_w
author_rank: Super Contributor
timestamp: January 04, 2022, 11:39:47 pm
content: The problem with putting the encoder on the rear motor shaft is now you are not taking into account backlash of the gears.It looks way too small for me. You probably want a servo or stepper motor, or give a better description of what you are trying to accomplish.What precision is needed on that main gear shaft?

author: Benta
author_rank: Super Contributor
timestamp: January 06, 2022, 06:00:47 pm
content: Quote from: Infraviolet on January 03, 2022, 05:25:02 pmLogic flaw in your thinking: you'll get increasedresolution, butnotincreasedprecision. It's two different things.As @thm_w says, the gearbox backlash will be in the way.

author: Infraviolet
author_rank: Super Contributor
timestamp: January 12, 2022, 09:09:27 pm
content: Thanks both, should have thought of that limitation. The back end encoder idea use was really to measure exact speed rather than position, and I had planned on placing a second encoder on the driven items to get position better, but thought I'd get a betetr speed estimate by measuring the quickly moving backshaft.
Standard Brushed DC Motor Sizes - Page 1
Forum section: electronics / general

author: dapeake
author_rank: Newbie
timestamp: October 22, 2021, 12:36:36 am
content: Is there a reference or a standards organization that has settled on a set of physical guidelines for Brushed DC motors, like those found in small toys? I have seen numbers such as N20, Type 130, etc... but I have not seen a unified standard of specifications. (kinda like NEMA)For this product I am developing, I bought a motor from Digikey which they called a "standard motor". It's great, low cost and way outperforms it's datasheet.https://www.digikey.com/en/products/detail/nmb-technologies-corporation/PPN7PA12C1/2417079?s=N4IgTCBcDaIA4EYAsBmArGgtAOwCYgF0BfIA.I felt it was safe to invest time into - I created drive circuitry and firmware, resin prints of the product enclosure, etc... - but it has a 1.5mm shaft, and I have found it extremely difficult to find plastic gears that are for 1.5mm shaft. And, making plastic injection molds around a completely proprietary motor seems unwise. So I need to speak the right search language in finding a replacement, or confirming that this motor is indeed in compliant with a standard. Any help in finding a library of standards for toy sized DC motors would be greatly appreciated!Thanks,DanSan Jose, CA

author: beanflying
author_rank: Super Contributor
timestamp: October 22, 2021, 01:18:19 am
content: No real standard other than Mabuchi is sort of a defacto standard for their own and the hundreds of clones but this is still only a portion ( a fairly large one) of the options.https://www.mabuchi-motor.com/product/knowledge/classification/designations.html

author: dapeake
author_rank: Newbie
timestamp: October 22, 2021, 02:15:04 am
content: Great link. Mabuchi is quite massive. This is a step in the right direction. I bet I will be able to cross the motor I have to their catalog.Thanks,Dan

author: salihkanber
author_rank: Regular Contributor
timestamp: October 24, 2021, 09:22:14 pm
content: I don't think there is, afaik each manufacturer has its own sizes and standards such ashttps://www.portescap.com/en/products/brush-dc-motors/all-dc-motors

author: dapeake
author_rank: Newbie
timestamp: October 24, 2021, 09:51:42 pm
content: Thanks, that's a great catalog of highly efficient motors. I bet they are pricey!Thanks,Dan

author: Infraviolet
author_rank: Super Contributor
timestamp: January 03, 2022, 05:29:13 pm
content: For motors with a gearbox fitted the 37mm size and "micrometal" style seem pretty consistent across many manufacturers. Gear ratios and current consumption vary wildly, and motors in the sizes are specified for different typical voltages, as well as sometiems having a rather different shape to their terminals on the rear, but the overall size and shaft specifications stay consistent across many producers.
The Signal Path review of Makera desktop CNC. - Page 1
Forum section: electronics / general

author: Bud
author_rank: Super Contributor
timestamp: December 06, 2021, 04:18:50 pm
content: Shahriar of "The Signal Path" channel reviews a shmick CNC machine on Kickstarter and mills a PCB mictowave filter with stunning mechanical quality.https://youtu.be/oJcUJMcSak4
New CNC Machine - Page 1
Forum section: electronics / general

author: Pack34
author_rank: Frequent Contributor
timestamp: November 29, 2021, 09:57:08 pm
content: New setup with a Shapeoko 4

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 30, 2021, 04:51:15 am
content: nice! i still waiting for the time to build bench and drawers like that for my exposed-in-the-air diy CNC setup.. and custom CNC/CAM SW for it too...

author: Pack34
author_rank: Frequent Contributor
timestamp: November 30, 2021, 03:24:51 pm
content: This is parked in my garage in my townhouse so I needed it to be fully enclosed to keep noise down as much as possible. There's a shop vac in the bottom with a hose running up to the top. The shop vac ended up being louder than the CNC itself so I picked up a speed controller for the vac. It really only needs to be running at 50% to extract the material being cut away and that substantially drops the noise level. The cavity for the vac also has insulation all sides to muffle it further.Integrated lighting, emergency stop, etc.

author: PlainName
author_rank: Super Contributor
timestamp: December 01, 2021, 10:48:16 pm
content: Nice job
Precision and Rigid milling machine - Page 1
Forum section: electronics / general

author: xzswq21
author_rank: Frequent Contributor
timestamp: November 25, 2021, 08:19:53 am
content: I wanted to buy a WABECO F1210HS ISO30 and spend $7000 for the machine but many people have reported that the head is made of Aluminum and the machine is not rigid.I want the machine to make small things but for small or medium production. (not for hobby)What do you think about the OPTImill MH 25V or other milling machines?OPTImill MH 25V, the price is $4000:https://www.stuermer-machines.com/me...h-25v-3338155/The spindle speed of the OPTImill MH 25V is 200 to 4000 RPM so it's not perfect for the end mills with a diameter smaller than 10mm (3mm to 6mm) but sometimes the speed should be higher than 4000RPM.You see the cutting speed etc for the OPTImill MH 25V at page 32 and 33 of the below document:https://www.cnc-shop.mobasi.com/down...eng-manual.pdfBut how much is the milling machine accurate? I should make small things within +/- 0.025mm accuracy. but in my general work it can be +/- 0.1mm or +/- 0.05mm.It's interesting Optimum hasn't reported the Runout or table flatness of the machines, WABECO reported anything and I'm pretty sure they have used several Japanese parts in their productions and they reply all your questions! But Optimum is not responsible.

author: Benta
author_rank: Super Contributor
timestamp: November 26, 2021, 10:02:28 pm
content: I'm really irritated now, and I apologize for recommending the F1200/1210 earlier. It seems Wabeco has caved in to cost savings over the last years.My 20 yo. F1200 has a pretty massive cast iron head, and all the other structural elements of the machine are cast iron as well. And without casting faults.That it's suddenly thin-walled aluminium is completely new to me.A comment to the guy in the video: he's milling C45 steel (which is the most horrible material that you can work with), and he's doing it without cooling/lubrication. A total no-go.The MH 25V looks nice, I'd go for that as well if I didn't already have a mill.