Share tips you have come across

Using Arduino General Electronics
#104

A while back, I was using solvent to glue up acrylic boxes.
The trick was to get one drop of Methylene Chloride (causes cancer in California) at the junction of two pieces of plastic to form a right angle.
I came up with a design, to what I refer to as a “Capillary Dropper”.
The dropper must serve two functions, #1 dispense only one drop at a time, #2 place that drop at a precise location.
Below are images that describe what is necessary to make one of these droppers.
Note: the larger the diameter of the capillary rod, the more liquid will be dispensed (up to a point).
I find a rod diameter of .026” in a syringe needle with a diameter of .039 works best for one drop at a time application.

Capillary rod diameter:
Straight pin, .026"
Pin with yellow ball on end, .026" <-----<<< best for one drop at a time
Sewing needle, .035" <-----<<< best for almost a continual flow at a seam

I will follow up later with “Attaching a PCB inside a plastic case without drilling through the project box itself”.

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#105

Attaching a PCB inside a plastic case without drilling through the project box itself.
Drilling holes in a project box, front panel or bezel usually leaves an amateur look to your work.
There isn’t anything wrong with screws they can just be a bit unsightly, especially if there are a lot of them.
Below are images showing how you can mount PCBs, sensors, LCD displays etc. to the inside of a project case or behind a front plastic bezel.
The first thing you need to identify is what solvent you need to go with the type of plastic you are working with.
Methylene Chloride, Acetone, MEK etc. are common solvents used for welding plastics.

Let’s say we have a PCB with 2-56 size mounting holes and we want to attach this to the inside surface of a white piece of acrylic plastic.
We need four small 1/8-inch-thick acrylic standoffs/spacers.
We will drill a #47 size hole in each standoff and thread these holes with a common 2-56 screw.
Here we have a strip of 1/4-inch-wide by 1/8-inch-thick acrylic with #47 holes drilled in a line.
Using a slow speed electric screwdriver and a stainless steel 2-56 screw, each hole is threaded.
After threading, a cut is made about half way between each hole.
This leaves us with plastic 2-56 four cornered nuts.
The 4 standoffs are mounted to screws so the standoffs are in line with the PCB holes.
Using a Capillary Dropper, one drop of methylene chloride is added to the side of each plastic nut.
After about 20 seconds the solvent welds the acrylic nut to the acrylic panel.
In about half an hour the assembly is cured.

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#106

Excellent idea Larry! Where do you get the acrylic strip from?

#107

LarryD:
@Jiggy-Ninja
The Hakko soldering iron tips are great.
It is nice to have an assortment of shapes and sizes for different soldering jobs.

As I mentioned in a previous thread, this is my new goto soldering iron tip of choice:

Edit
I shouldn’t have used goto ???
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I can’t remember if this was brought up in here or in the previous thread, but Hakko has some great references about choosing tips. This page details the uses of the different shapes in the T18 series (Weller probably has a similar page, I just don’t have one). The bent one you posted is type J.

My vote for the champion of the “unexpectedly useful soldering tip” category doesn’t go to the crooked type J, but to the type K Knife tip.

Yes folks, this is not a cutting attachment, it is a proper soldering tip. Hakko described it’s advantages thusly:

This type has a shape like a knife and is capable of soldering by applying the tip in 3 ways: line, face and point.
It is used for soldering at narrow pitches, correction of bridging and drag soldering.

How to use.

That first image in there is just awesome; through hole drag soldering. I tried it last night on a 20 pin ZIF socket and it with the ability to start heating the next pin while one is wetting it probably took less than 15 seconds to do each half with the fine solder I was using. If I used my thicker roll it would have probably been a hair faster.

I can’t wait to try a TQFP or maybe even a lead-less package with this. I just need to make some progress on the parts of my projects that I’m stuck on.

#108

Yes that tip is very useful.

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#109

Where do you get the acrylic strip from?

Trotec https://www.engraving-supplies.ca/

Two methods I use: Make them out of a 12" by 24" sheet of the material (1/8 inch thickness).

Manually: use a 1/8 inch carbide router bit with a fence positioned at 1/4 inch. Run the sheet the full length which gives a strip 1/4" X 24" You can of course move the router fence to get whatever width you need.

Since the bit is 1/8" you lose that amount of material when you make the cut :(

Automatic: I have also used a CAM Tool (CNC) to rout the strips to required width. During this procedure, a pilot hole is also drilled. The nuts are "V" scored to 1/16" depth halfway between the pilot holes prior to routing. Finish the pilot holes on a drill press to the size required for the screws, 2-56, 4-40 or 6-32. After threading, I complete the "V" scored cut using a table scroll saw with a metal cutting blade, but lately I have just been snapping the threaded nut off the strip.

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#110

Further to post #104

Note, the screw is being used as the standoff method here.

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#111

There are several types of bezels available for mounting single LEDs.

I do not care for the metal version that comes with a nut.

I very much like the mounting hardware in #4 and like the home-made version of #2 and #3.

Below are different methods, I usually use:

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#112

LarryD: I do not care for the metal version that comes with a nut.

Why not?

#113

LarryD:
I do not care for the metal version that comes with a nut.

pert:
Why not?

Like me probably forgets to put the nut and washer on before soldering to the leads.


Tom… :slight_smile:

#114

I love this thread, talk about great tips and tricks posted here. I definitely want to see and contribute more to this thread.

I'm going to start off with a real simple one that many of you probably already know and use but here it is anyway.

I always keep my strips of used Solder Wick and have used them for a couple of things.

1- Add solder to get rid of any of the exposed braiding and use it for ground straps. 2- Lay it down on PC Board Traces that don't seem robust enough to handle higher currents and then flood it with solder. It even works great to fix a trace that has actually fried. Done properly it looks good and well no burnt traces.

#115

I have used the silver/chrome coloured bezels but prefer the black/matte finish of plastic.

I have not tried these yet:

As mentioned these are a good version.

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#116

Twisting wires can help keep your projects more organized and manageable.
Twisting can cause some signal cross talk between wires, however, for short distances and the frequencies seen in Arduino projects this is usually negligible.
The images below present some ideas you might want to use in your next project.

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#117

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#118

Hi, I use post #116 to make twisted pairs.

I SET the twist by briefly running the heat-gun up and down the twist before releasing it. It relaxes the insulation and helps to get even twist.

Tom... :)

#119

technogeekca: I love this thread, talk about great tips and tricks posted here. I definitely want to see and contribute more to this thread.

I'm going to start off with a real simple one that many of you probably already know and use but here it is anyway.

I always keep my strips of used Solder Wick and have used them for a couple of things.

1- Add solder to get rid of any of the exposed braiding and use it for ground straps. 2- Lay it down on PC Board Traces that don't seem robust enough to handle higher currents and then flood it with solder. It even works great to fix a trace that has actually fried. Done properly it looks good and well no burnt traces.

That would increase the current handling of a trace quite nicely. Regular bus wire works also and surplus solder.

See EEVblog:

https://m.youtube.com/watch?v=L9q5vwCESEQ

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#120

TomGeorge: Hi, I use post #116 to make twisted pairs.

I SET the twist by briefly running the heat-gun up and down the twist before releasing it. It relaxes the insulation and helps to get even twist.

Tom... :)

Just tried this, works well ! :)

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#121

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#122

LarryD: That would increase the current handling of a trace quite nicely. Regular bus wire works also and surplus solder.

Yes you are absolutely correct.

To clarify what I didn't properly state before is that I use it on wider traces and generally wider traces that have been burnt open. This allows me with a bit of prep and cleaning to almost completely cover the burnt section so it's almost invisible.

Thanks again for all your amazing tips.

#123

When you loom your cable harnesses, the point of termination requires some thought.
I prefer to use the loop method as it gives slack to the wires.
If wires need to be re-terminated or moved you have the slack to do so.
The eye is less forgiving when the loop method is used. :wink:

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