Day: February 28, 2019

Threading 3D Printed Parts: How To Use Heat-Set Inserts

February 28, 2019 by 57 Comments

We can make our 3D-printed parts even more capable when we start mixing them with some essential “mechanical vitamins.” By combining prints with screws, nuts, fasteners, and pins, we get a rich ecosystem for mechanism-making with capabilities beyond what we could simply print alone.

Today I’d like to share some tips on one of my favorite functional 3D-printing techniques: adding heat-set inserts. As someone who’s been installing them into plastic parts for years manually, I think many guides overlook some process details crucial to getting consistent results.

Make no mistake; there are a handful of insert guides already out there [1, 2]. (In fact, I encourage you to look there first for a good jump-start.) Over the years though, I’ve added my own finishing move (nothing exotic or difficult) which I call the Plate-Press Technique that gives me a major boost in consistency.

Join me below as I fill in the knowledge gaps (and some literal ones too) to send you back to the lab equipped with a technique that will give you perfectly-seated inserts every time.

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Does WiFi Kill Houseplants?

February 28, 2019 by 72 Comments

Spoiler alert: No.

To come to that conclusion, which runs counter to the combined wisdom of several recent YouTube videos, [Andrew McNeil] ran a pretty neat little experiment. [Andrew] has a not inconsiderable amount of expertise in this area, as an RF engineer and prolific maker of many homebrew WiFi antennas, some of which we’ve featured on these pages before. His experiment centered on cress seeds sprouting in compost. Two identical containers were prepared, with one bathed from above in RF energy from three separate 2.4 GHz transmitters. Each transmitter was coupled to an amplifier and a PCB bi-quad antenna to radiate about 300 mW in slightly different parts of the WiFi spectrum. Both setups were placed in separate rooms in east-facing windows, and each was swapped between rooms every other day, to average out microenvironmental effects.

After only a few days, the cress sprouted in both pots and continued to grow. There was no apparent inhibition of the RF-blasted sprouts – in fact, they appeared a bit lusher than the pristine pot. [Andrew] points out that it’s not real science until it’s quantified, so his next step is to repeat the experiment and take careful biomass measurements. He’s also planning to ramp up the power on the next round as well.

We’d like to think this will put the “WiFi killed my houseplants” nonsense to rest – WiFi can even help keep your plants alive, after all. But somehow we doubt that the debate will die anytime soon.

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Inside The Secret World Of Crimping

February 28, 2019 by 34 Comments

At some point in your electrical pursuits, you’ll need to make a connector. Maybe you’re designing something that will connect to another device, or maybe the spaghetti mess of wires coming out of your Raspberry Pi has become a pain to deal with. Whatever the reason, a proper connector can solve a lot of headaches in electronics projects.

Your first thought might be to run to your favorite component distributor and order the connectors, terminals, and crimping tool. Unfortunately, those tools can cost thousands of dollars. Maybe you’ll just solder the connectors instead? Don’t! It makes for easily damaged connections.

Fortunately, [Matt Millman] has a great guide on wire-to-board connectors. This guide will explain why you should never solder crimp terminals and then get into working with some of the most common wire-to-board connector families.

For example, the Mini-PV series (which often get called “Dupont”) are one of the most ubiquitous connectors in hobbyist electronics. They’re the connector on those rainbow colored jumper wire sets, and connect perfectly to 0.1″ pin headers. The connectors and terminals are cheap, but the official HT-0095 crimp tool costs over $1500. Most crimp tools make a mess of these terminals since they require a cylindrical jaw to crimp correctly. By using a combination of two unofficial tools, you can crimp these connectors properly for under $60.

If you want to learn more about the art of wiring, the NASA Workmanship Standards are an interesting read.

[Thanks to MarkMLl for the tip!]