Wednesday, June 15, 2016

Static shielding and how some online sellers are hurting the maker community

As a maker with an embarrassing number of years of electronics experience, I am a little concerned by the haphazard way many makers handle their projects. Better understanding of how sensitive many electronic devices are can save us hours of pondering over glitches, and can help ensure the projects we spend so much time working on survive long enough to be really useful. You are going to be opening up your Wink hub to connect directly to it, you should observe proper anti-ESD precautions to avoid damaging it. ICs that must connect to the outside world often have rather robust ESD protections designed in, but once you open the case up and start poking around, you may find that the internal connections are more easily damaged by static discharge. It only takes 50V to arc over a MOSFET gate. Your body can easily develop hundreds or even thousands of volts, depending on humidity, clothing, shoes, flooring, etc. Creating a static charge is as simple as touching one object to another and then pulling away. This could be fabric, plastic, metal, cork, carpet, wood, the plastic body of an IC or insulation on a wire, fur, hair, rubber, etc. There are some basic precautions you can take without spending a lot of money on an entire ESD dissipative workstation. However, considering the fact that you are already embarking on a process of learning electronics, an ESD mat is a very good investment. Small desktop ESD dissipative mats can be bought for $15 to $25 at local office supply stores or online. Get a wrist strap, too, if it isn't included. Do NOT buy a "wireless wrist strap" or any other device that claims to remove static charge wirelessly, they are provably ineffective. Here is a foldable portable anti-static mat with wrist strap: For something more durable, this mat rolls and once you include the price of a separate wrist strap, the price is about the same: Here is a wrist strap to go along with that mat: Connect the ground cord of the mat to a reasonable ground. The screw on an AC outlet, the ground connection on an AC outlet, or a metal water pipe. It isn't enough to just connect to something metal, that is worse than not connecting to anything at all. If you have a metal outlet strip, the metal body should be grounded when it is plugged in. Connect the wrist strap wire to the ground connection on the mat, then put the wrist strap on. Now set your Wink Hub on the mat and you can take it apart and work on it. To solder wires in, you should be using a grounded soldering iron or soldering station. Grounded soldering iron: Temperature controlled soldering station, suitable if you are going to do a lot more soldering: More information on electrostatic discharge, protections, and procedures: http://www.esda.org/fundamentalsp1.html http://www.minicircuits.com/app/AN40-005.pdf http://www.ti.com/lit/an/ssya010a/ssya010a.pdf ESD Protection Webinar: http://www.digikey.com/videos/en/v/ESD-protection-Webinar/1680491988001 So you don't think modern electronics require ESD protection? http://electronicdesign.com/power/esd-smartphone-s-worst-enemy Dave Jones of EEVBlog did an episode testing the efficacy of silvery static shielding bags versus pink antistatic bags, illustrating how antistatic bags merely don't generate a charge of their own but provide no protection. https://youtu.be/imdtXcnywb8 Video at top of page.