Instructables

DIY Anti Static Mat

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An inexpensive solution to a reasonably expensive, albeit necessary, electronic soldering accessory.


This is my first Instructable! Please give adviceconstructive criticism, AND PRAISE! (I can't believe I forgot to list the last one. Jeez!!! :)


[EDIT: As one commenter suggested, (and I failed to realize) your mat should have a conductive top layer and a non-conductive bottom layer, NOT the three layer /resistive-conductive-resistive/ version I have made here. I haven't yet found a proper substitute for the aluminum (it is not durable enough to use as a top layer). I will edit this -Ible to reflect the correct 'two-layer' assembly once I have the proper material for an acceptable price! (Free.... Obviously...) Thanks for reading on!]
 
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Step 1: Explanations

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All Anti Static mats, aka ESD mats, have one purpose - to dissipate the static charge that can, and usually does, build up on the human body during a typical day in a controlled manner. This condition can cause a short in your components from a rapid discharge of electrostatic energy. Really creative name for the mat, huh?

To be more accurate, an Anti Static mat drastically slows the rate of static energy discharge or maintain at zero, the difference in the common electrical potential of the operator relative to the many components he, or she, may come in contact with. This eliminates the possibility of discharging the static into a sensitive electronic component possibly causing it irreparably damage.

The mats are typically constructed of an electrically resistive rubber or plastic derived material combined with a conductive layer that leads to a ground plane such as a three pronged outlet (here in the US) or a grounding rod in the ground outside of your hobby shop. See the two images above for an example.
Some mats implement a direct connection with the operator through a wrist strap or floor mat. The bench top mat that I am constructing will use a wrist strap to provide a complete circuit from the skin, through the mat, and into the chosen grounding plane. As I understand things, this setup can provide a more stable and consistent rate of discharge over a day's work period.
ESD mats will usually have at the least a 1 mega ohm resistor inline with the circuit somewhere to slow the rate of ElectroStatic Discharge and prevent shock from the grounding plane reaching the operator.

stinkyoldguy6 months ago

I do much the same as keanja and have not had any problems. I have a "huge" anti static bag I scrounged from a server motherboard that I use as an assembly surface (on top of Formica bench top) and a couple of smaller bags that I can use for protected storage.

And if you need to use a wrist strap is easiest to clip it to the computer chassis you are working on.

Robert42111 year ago
I found your instruct-able while searching for anti-static foam to line a drawer for hard drive storage. I now know what to do with those 1 meg ohm resistors too. Now I just need a 16 foot long piece of foam to cover my workbench :). Thanks for all the info!
Best, Rob
keanja1 year ago
I have been working on electronics for 30 + years and I have never used pads. I have always observed some common sense rules. 1. Have a truly grounded outlet (not something someone has hacked to have 3 prong outlets with 2 wire systems with no ground wire as most computers have 3 prong connectors). 2. plug the computer into the outlet when servicing with the computer OFF. 3. Touch yourself to the metal chasis as you work, often. 3. Before opening a computer touch the metal near where the plug plugs into the computer. 4. If working on a notebook computer have a old desktop to do the above with. 5. Use the anti-static plastics bags that components come to set them on when you need to put them down. 6. Always handle components by the edges.
This is a good idea, but your top layer should be conductive with some resistance such as the black foam that components are shipped in. You don't want " the more resistance the better", you want to disipate the static to ground as quickly as possible & yet not cause a short circuit or shock hazard , should the circuit be powered up while touching the pad.I have used the pads that are sold for use under computer keyboards, they are a small anit-static pad & usually much cheaper that the regular ones. Cheers!
Maker T Elam (author)  Lectric Wizard2 years ago
I haven't seen ESD pads for your keyboard. I'll look around!!!! Thanks!
Maker T Elam (author)  Lectric Wizard2 years ago
I see c181155. I should change the top layer. I figured the connection from me, through the wrist strap, and into the aluminum/copper wire, and into the ground plug was enough of a conduit.
Speaking of which, does anyone know of a forumla that will give you a general target to shoot for as far as resistance. Everywhere I read up on the subject, I read numbers in 1*10 to the 6th and 7th power Ohms. But I had no idea why.
david3392 years ago
Why is threre a need of a conductive top layer?
Maker T Elam (author)  david3392 years ago
The conductive layer completes the circuit between you, the device, and the ground plane (if you aren'e wearing a grounded and conductive wrist strap). My understanding is that your body builds up the charge. Then you grab the VERY sensitive electronic part without a conductive mat (that slows the rate of discharge to ground) sending the spark to your part but it has no where else to go. ZAP! Or... I could really have misunderstood everything I read.
Honestly, what ever you do when working with electricity. DON'T, I REPEAT DON'T, let the smoke out or everything stops working. Its horrible. Just horrible...
mdog932 years ago
"Material:
1. One electrically resistive layer. (The old yoga mat)
2. One electrically resistive layer. (The aluminum foil)"

Did you not mean '2. One electrically conductive layer. (The aluminium foil)'
Maker T Elam (author)  mdog932 years ago
AH! Right you are! Thank you! Will edit that tonight!
The top must allow the static electricity to drain away to ground,the insulator would prevent this. The overall resistance is chosen in the million ohm range because static can carry thousands of volts. That lets the higher voltage drain but maintains current at lower voltages to a safe level. As pfred2says it not that big of a problem most of the time but when you are handling chips worth hundreds or thousands of dollars each it is a good idea !
pfred22 years ago
I'd rather take my chances with static than shorting out. I don't have issues with static discharge damaging modern electronic components today. Fabrication processes and designs have improved considerably from the bad old days when you just looked at a CMOS IC wrong and it blew out.

Wearing wrist straps drives me nuts too. So thanks, but no thanks.

One board fabrication house I worked at we used plain white foam to stuff PCBs on because the boss hated using anti static foam, "it costs too much". The white foam beads would cling to stuff it was so charged up, no problem!

Static damage to electronics is mostly hysteria as far as I'm concerned. But hey whatever makes you feel better.