47

Here's what happened to a product I designed that was IP69K (Protection against powerful high temperature water jets). It was installed in China and failed after about a couple of years. When looked into there was about 1.5 inches of water slopping about. Seemingly a mystery. However, it turned out to be a progressive build up of humidity. Every night the ...


31

You can buy (or 3d print) fasteners made for such a case. Search PCB mounting feet. These include a standoff to help cooling and prevent shorts.


27

Cut a piece of pcb stock (or any sheet plastic) to fit properly in the housing, including screw holes to match those bosses. Then attach your components to this base plate either with double sided tape, velcro, or cable ties going through holes in the plate. Run the cable through a notch in the edge of the housing rather than a hole so it can be easily ...


20

I would try something like that: You assemble like that, put crazy glue on the legs, let it dry in the container. Then you can unscrew when fixed to pick up the device.


19

I do a lot of lighting projects for props, theater, and holidays (like Halloween). "Glow" effects are frequently wanted, so you have to diffuse the light source in order to avoid having the point source visible. There are several ways that I do this, so I'll just list some of the techniques here: Diffusers: Depending on the type of light, not all diffusers ...


19

Andy exactly describes the mechanism I have also seen . Because of this I favor inverted bucket case designs which do not rely on seals, wherever possible. "The definition of waterproof is the hole in the bottom is bigger than the hole on top" Note on "trapped humid air when box was closed" At 25C, there is 22g/m^3 of water, or 22mg if this is a 1L box. ...


18

I once found water in a box like that installed INSIDE a house. I was baffled about where it could come from. Turns out the water wicked itself through the wire going into the box, coming from another (similar) box on the roof that was full of water. So basically the electrical wire was operating as a hose. I can't see very well on the picture you're ...


15

Just leave generous clearances and you should be fine. Even with well designed and made boxes (eg. Hammond) it's not unusual to allow a couple mm overall clearance (1mm all around). Eg. (from above datasheet- maximum recommended PCB size) Maybe you want to allow 1.5mm rather than 1mm if it looks a bit rough. Shrinkage (typically a couple of percent in ...


13

You buy the complementary inner panel/base plate to mount your products on. It will fit matching the mounting holes, and it will arrive with the correct set of fasteners. Or you could just make a PCB matching the mounting holes. images from Hammond MFG.


12

Does painting (non-conductive) over the top of a grounded metal enclosure affect its ability to absorb/block RF interference? No, the idea of an EMI enclosure is to create a faraday shield around something to block electromagnetic waves around whatever it is enclosing. The shield itself needs to be conductive to be effective and have adequate skin depth, ...


11

While this isn't an electronics question in itself, it is a problem faced by many of us when finishing off an electronics project in an attempt to create a professional finish. It is most likely done by a screen-printing process. These are low-cost for one-off or low quantity production runs. Figure 1. A screen-print jig. Source: Guitar Fool. The linked ...


11

What you want is to prevent condensation from the thermal difference between the case and internal air. This depends on the relative humidity of the internal air to not exceed the dew point. IP67 specifies prevent vapor pressure leaks submersed to 2~3m under water tested for >=1hr as per supplier specs. IP66 only protects against external water spray ...


11

The small standoffs molded into the bottom of that plastic box can be used with the proper sized metal machine screws. The screws will cut their own thread in the soft plastic. There are several things to consider: Make sure to select the proper diameter machine screw. Make sure to select a machine screw that is not too long. If too long it can bottom out ...


10

Connecting a metal chassis to ground obviously helps with shielding. For an analog circuit where sensitivity to noise and ground currents must be avoided, such as those dealing with audio or video, you are correct that to connecting at just one point is best. But for many cases (excuse the pun), it really doesn't matter as much. Further, if it is a circuit ...


9

I use Industrial-grade hook-and-loop fastener material (also known as Velcro). This works extremely well and is reliable over a long period of time. It's easy to remove and replace the individual boards as needed. The stuff we use comes from Aplix. If you do a electronics.stackexchange search for "Aplix", you will find the part number of the Aplix product ...


9

You could try this: cut two pieces of rubber or soft plastic pipe or hose, a little bit longer than the PCB. Cut a groove on their side and insert them on both sides of the pcb. Then drill holes throught the pipe to fix them in the case. Attention: the picture is not related to my answer. Just gives a visual idea.


9

The "Particle Photon" board (who makes these goofy names?) consumes 80 mA at 5V, making its power dissipation at 400 mW. This is a pretty substantial power consumption, and the heat must dissipate via build-up of temperature difference between the board and ambient air. If you want your sensor and MCU inside one enclosure, you should find a way to reduce the ...


8

(1 mm steel is thick!) The isolation may not be required, since you're probably (S)ELV. Anyway, it's not going to cost you much space-wise. I wouldn't mess with paint sprays and such. Agreed, it's the thinnest, but I assume you can afford the thickness of a 0.1 mm PP (PolyPropylene, PP has very low water absorption) sheet? Try to use only SMT parts, and ...


8

This isn't really a full answer but just to contribute. Fiber Glass I once spent a lot of time designing an enclosure that had to live outside in the full sun, near the beach so we had to deal with salt spray. Oh and of course management wouldn't stand for any color changes in the plastics, and metal couldn't be formed to the pretty shape ID wanted... ...


8

A soapbox is hardly a standard unit of measurement, but 12 W doesn't require anything too huge, even without forced air, provide you can at least let natural convection be, well, natural. Here's how you calculate the heatsink you need. I've picked the datasheet for IRF510 as an example. It's a very common TO-220 MOSFET and should work for your application. ...


8

Figure 1. Relative size of box-top screws and PCB mounting holes. If those are M3 screws for the lid then it looks like the mounting posts are about 3.5 mm outside diameter and maybe 1.5 mm inside diameter. You're looking for a short self-tapping screw with a 2 mm thread. Figure 2. A selection of 2 mm self-tapping screws. If you have a set of drill bits ...


7

Moisture ingress protection: Unless you are willing to completely encapsulate your circuitry in epoxy or similar, you will have to deal with water ingress into your electronics cabinetry. In general there is no guaranteed totally sealed box, if you have water vapour, temperature cycles and a sealed container it is a certainty that water will find it's way ...


7

One popular and traditional hacker enclosure has been the classic metal Altoids peppermint can - to the extent that some products and prototyping PCBs are shaped to precisely fit one. (Image from Adafruit) For more examples, see a toy, an amplifier and another, a sound generator, a USB charger, one could go on all day. A fringe benefit of using a metal ...


7

You don't drill such holes. Instead, you get a punch. For instance, if you're trying to install BNC connectors you need a 1/2" D punch, such as this... And yes, they are expensive. Prototyping will use this sort of punch, which is hand-powered. For production you get a punch/die set for a press.


7

The spring mechanism appears to be part of a centrifugal switch arrangement, which would be crucial to getting the motor started. Trying to start the motor without it would result in no rotation and excessive current draw.


7

An image search for "glanded miniature terminal box" shows up the following products. Figure 1. Something like this should do the trick. You need three terminals for cable termination and resistive divider component termination.


6

The transformer doesn't have mounting tabs because it's for PCB mounting. Solder it on a piece of breadboard ("Veroboard") with some space around it, and drill 4 holes on the corners for bolts. Since you're using a breadboard anyway, use it to mount connectors for connecting both the primary and secondary. Don't solder your power supply cable directly to the ...


6

My two favorite places are OKW Enclosures and Polycase. They have off the shelf options in different styles, no minimum order. They will even do customization on small orders too, i.e. drill holes, silkscreen, etc. If you can't wait and you are lucky enough to live next to a Fry's electronics, you can walk over and pick up a simple one for not much ...


6

Most electronics shopping involves parametric searches. To use these effectively you need to know the terminology, which makes it difficult to get started, but a lot can be inferred with a bit of common sense. As a start, I'll work from the two mainstay distributors, Digikey and Mouser. Both links point to sections dedicated to enclosures. It's also ...


6

One thing is worth considering and I think this is quite important. Here's the story: - An IP69 product that was shipped to China for taking measurements of metal contaminants on a food line. It was switched-off every evening after the last shift. After about a year it failed to power up one morning. Upon opening the bottom panel (which housed the switch-...


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