Strain Relief for Rough Prototypes

Most of Pocobor’s projects involve integration of electronics and software into a physical, mechanical system. Any single weak point in this integration can jeopardize the entire design; with the individual subsystems already complicated enough, we can’t afford to have weak interconnections between them. Of all the possible failure points, there is one that stands out to me as being both particularly devious and simple to mitigate: loose wires. A loose electrical connection can be extremely difficult to find and can wreak havoc on any electrical system. But there is hope for all those loose wires out there — strain relief!

I like to think of strain relief as a mentorship program for loose wires. Without a sturdy companion to provide guidance and assistance, a loose wire may find itself getting caught up in undesirable activities (maybe a rotating motor shaft or a passing foot). Sometimes this mentor is another, larger wire — there’s safety in numbers — or sometimes it’s a sturdy mechanical component in the system. A link is made between the loose wire and the mentor, and future snags are much less-likely to cause significant damage. Sure, our little loose wire might get pulled in dangerous directions, but his mentor will be right there beside him to provide support.

Three simple ways to add effective strain relief to essential wire connections in rough prototypes: zip ties, heat shrink, and hot glue. I’m focusing on rough, quick prototypes in this post (hot glue probably isn’t the best solution for manufactured products), but many of these techniques can apply for finished products as well.


Zip ties can significantly reduce the forces on electrical connections. Here, the red zip tie is linking the large and small black wires together well below the electrical connection within the red wire nut.



The yellow zip tie shows the strain relief for the wire bundle leaving the breadboard. In this case, I’ve zip-tied the bundle to a hole drilled in the edge of the breadboard.



The yellow heat-shrink joins the small black wire to the larger grey wire to reduce forces on the electrical connection. Heat shrink used in this way also reduces the chance of an electrical short circuit.


This very rough prototype shows the value of hot glue for strain relief. In this example, I’ve soldered small wires (green) to a surface-mount sensor (small and delicate connections!) and have used hot glue to keep them from moving around and breaking loose. You can also see the strain relief for the green wires’ heat-shrink connection to the wires leaving the board. Those (larger) black, white, and teal wires are going to protect the delicate connections if they ever get yanked.

Loose wires can get snagged, pulled, bent, melted, or trampled. Whether you’re connecting to a breadboard or a PCB, wires that enter or leave the electronics should be properly strain relieved. The small amount of time it takes to strain relieve a wire can save hours of stressful troubleshooting and/or repairs down the road. The important thing to remember is that strain relieving wires is not necessarily going to prevent them from getting yanked or twisted or snagged, but it will prevent the force of that snag from reaching a critical electric connection in your design.

As Engineers, there are many things that we can’t easily control (stray electro-magnetic fields, the weather, apostrophe usage). Therefore it is essential that we take relentless control of the variables within our grasp. The universe tends to favor the chaotic monotony of loose, poorly-managed wires — fight back with strain relief!

The Democratization of Design

Who would have thought something that looks like a tinker toy could change the world?

The internet democratized information by making it orders of magnitude more affordable and accessible. New technology like the RepRap system shown above (http://reprap.org) has the potential to enable a similar revolution for hardware development by bringing similar scale improvements to the accessibility and affordability of mechanical design and prototyping.

RepRap is an open-source self-REPlicating RAPid prototyping machine. If you’re not familiar with this type of device, picture a printer that creates 3-dimensional objects instead of 2-dimensional pictures. Instead of depositing ink on a sheet of paper, 3-D printers deposit layer upon layer of material to make robust, 3-D parts. They are an invaluable development tool for prototyping and mechanical design because they allow a designer to bring his or her vision into the real world extremely quickly and cheaply so it can be tested and iterated on. Furthermore, they enable intricate, customized designs and shapes that can be created in a fraction of the time and without the labor required for traditional machining techniques.

Traditionally, rapid prototyping setups (e.g. FDM or STL) can cost hundreds of thousands of dollars or more. Engineers and designers have been restricted to using specialized prototyping job shops, who own these setups, to create rapid prototypes of their part designs. However, the design for the RepRap system is freely distributed under the GNU General Public License and (this is the really cool part) the system has been designed and developed so that it can create all of the non-standard parts needed to build a copy of itself. Add this to a cheap Bill of Materials due to some great design work by the people who developed the system and you have a 3-D printer that is relatively easy and inexpensive (on the order of hundreds of dollars) to obtain and use.

What does this mean? For starters, this means that thousands of designers who previously couldn’t afford rapid prototyping systems, both in the US and especially in other parts of the world, can now add small scale 3-D printers to their labs. Moving the systems in-house drastically increases productivity compared to dealing with external job shops and the associated details and headaches. It also creates the potential for a leap forward in the reach of the field of mechanical design. With easy access to sophisticated and powerful tools, engineers and designers will be able to utilize customized and optimized parts and systems instead of being restricted to readily available but non-ideal components.

Personally, I can’t wait to see what people start doing with these and to get one and try it out myself!

Poco-Intro: Akbar Dhanaliwala

If my name were a symbol. Eat your heart out Prince.

Hi I’m Akbar. Pronounced uck(like duck)-brr(like, “i’m freezing”).

Growing up in New Jersey, going to school in upstate New York, working in Connecticut after that, I dreamt my whole life of moving out to California. Partly I wanted to move to California to finally escape the Northeast winters, but the bigger reason was because I wanted to go to Silicon Valley, to be in the heart of what I thought was the best of American innovation.

Northeast Winters. At least how I remember them now.

About five years ago I decided to go for it. I packed up my car, said bye to my friends and family, and drove out to California.

Me in the badlands driving out to California. I was so inspired by the landscape that I fashioned my haircut after it. Not really.
Me in the badlands driving out to California. I was so inspired by the landscape that I fashioned my haircut after it. Not really.

Ok, I had made it to California, in the heart of Silicon Valley. And it was everything I had always imagined it would be like. The people here were smart, dedicated, innovative. But most importantly, I was surrounded by people, who, when you told them an idea, tried to think of ways to make the idea better, instead of immediately assuming it could never work and shooting it down. However, after a year in engineering graduate school I was stuck. I knew I wanted to be entrepreneurial, to be a part of something new and exciting. But I didn’t know what I was going to do. I had taken a lot of engineering classes, some more interesting, some less. I was in the design program, and I really enjoyed it, unfortunately I still hadn’t found the thing that I was truly passionate about…yet. Some people (me) say luck is just opportunity presenting itself to people who are prepared. I suppose it was luck then that helped me to find what it was that would eventually lead to Pocobor.

The beginning of my second year of grad school found me trying to figure out what classes I wanted to take for the year. There was a series of classes called Smart Product Design* (basically a series in mechatronics), that a few of my friends had taken the year before, and they all said how amazing a program it was. So I decided to take them. The class opened my eyes to the world of mechatronics. It showed me how creative a field it is, and that in the not too distant future all products will be smart products, and that mechatronics will be one of the bases for all design. In any case, after finishing a very intense year of classes, I knew, with no uncertainty, that mechatronics is what I was passionate about and that in some form or another, this is what I wanted to do. With the help of Brian who I had met during the series (as well as the Jo(h)n’s) and was just as passionate as me about what mechatronics meant to the future of design, we decided to form Pocobor.

What does mechatronics mean to me? It means bringing crazy wacky ideas like robots that clean your floor while you’re at work, or solar panels that follow the sun like some kind of cyborg flower to life. It means blending the best of mechanical engineering with electronics and computer software. It means thinking that anything is possible. And that makes me really excited.

Floor cleaning robot? Check.

*Smart Product Design is listed as ME218A,B,C,D at Stanford and is taught by Professor Ed Carryer, an amazing teacher.

Poco-Intro: Jon Thomas

I am Jon. I was born without an ‘h’—the doctors all said it wasn’t a big deal and that it happens sometimes. So far so good. We’ve got a John in our midst as well, so keep your wits about you.

I find that all great things in our world are a combination of other remarkable things. We see this in condiments: thousand island dressing and tartar sauce, for example. Who would have imagined that three of the primary condiments (ketchup, mayonnaise, and relish) could join forces so strongly to create such magnificent secondary condiments. Mechatronics is also a confluence of primary ingredients: Mechanical Engineering (ME), Electrical Engineering (EE), and Computer Science (CS). People say that mixed parents have the most attractive
children. I tend to agree; I believe Mechatronics is beautiful.

I grew up disassembling machines—lawnmower engines, bicycles, and VCRs—and trying to combine the pieces to build new machines (off-road motorized skateboards and pedal- powered wheelchairs–man, do i love wheelchairs!). More than anything else, I loved seeing how these devices worked—linkages, motors, bearings, gears, grease, pulleys. I was particularly drawn to mechanical systems, because I could actually see, touch, and smell the mechanisms. My interest in electronics and software came later (a circuit board doesn’t appear very exciting when you’re 10 years old, although those capacitors and ICs sure do resemble small cities) once I understood the invisible forces that make electrons do their dance. And that brings us to the present….what a joy it is to once again be building electro- mechanical devices, only this time I’ve added business cards to my arsenal! To me, Mechatronics is a way to be at the cutting edge of technology while still experiencing that
rush of discovery I knew from my childhood.

I am looking forward to sharing my thoughts on interesting topics surrounding Pocobor, and I am eager to hear yours as well.

Poco-Intro: John Pelochino

My name is John, not to be confused with Jon. We like the name Jo(h)n around here, it keeps it interesting/confusing. I’m pretty dam excited about this blog – a place to post my voice and spread the gospel of mechatronics. I’ll start it all off with a little blurb about me. I dig mechatronics – we get to play with electronics and make them do cool things in the REAL world. I’m a self-proclaimed tinkerer – why not take it apart? I like working in groups – nothing beats the energy in a brainstorm and you can’t really hi-five yourself (I’ve tried, not fun). And who doesn’t like a good hi-five? In the pocobor family, I’m probably the weird uncle – cracking random jokes at odd times and keeping things interesting or at least uncomfortable. That pretty much sums it up. Keep an eye on this blog – we play with knowledge, you’ll like it.

Poco-Intro: Brian Krieger

Hello world – my name is Brian and since this is my first blog post here, I guess I will introduce myself and also talk a little about why I am writing these posts. I am one of the partners at Pocobor and my background is originally in mechanical engineering, but I have been pretty focused on mechatronics and embedded systems for the last few years. Like the other bloggers here, I work full time as a mechatronics consultant / designer for Pocobor as
well as working on some mechatronics side projects that I am interested in. I also like robots.


From a big picture perspective, I am writing about this kind of stuff because I am very excited about the potential for really cool and useful innovations associated with mechatronics. I think that mechatronics (or integrated / embedded / electro-mechanical / [insert your pet terminology here] systems) is poised to change the way that we interact with the world. The Jetsons have seen the Future, and its name is Mechatronics (just kidding… but not really).

Cameron (one of the other partners and bloggers here) has a really interesting and much more detailed set of posts queued up for you that really dig into the ways that we see mechatronics changing the world and I don’t want to steal his thunder, but I told you I would try to answer the question “Why the hell does this blog exist?” The answer is: because we are deeply excited about the potential for mechatronics to make our lives more interesting, powerful, and happy. (It would also be disingenuous not to add that we are excited about our company’s
role in making that happen).

So that’s the big picture. The question now becomes “How can one help along that process?” We think that one answer is to create a vibrant mechatronics online community to share and discuss ideas, plans, and results. That is why we are adding our voice to forums like Mechatropolis, Mechatronics Zone and Bug Labs. We hope that we can reach people who are, like us, interested in mechatronics and its applications. We hope you will find some of
our ideas and activities thought-provoking and especially that you will let us know what your reactions are.

What kind of posts will be going up? Personally, I’m planning a roster of posts ranging from big posts describing some of the work I’m doing to little notes about anything mechatronics- related that I find interesting or cool. The first sequence of posts that I am working on will document the process of designing and building a device that will act as a lap counter for swimmers. This is just a project that I am working on because it interests me and my goal is
to let you know how I am going about designing and prototyping the device and also to solicit thoughts or suggestions on how to improve it.