Static

The Static Solution

Most teams know the wrath of static, what it can do to your robot, and how bad it can be during a match. If you don’t know what it does, here is the easiest way to describe it.

When there is a lot of static on the field it can cause trouble for the robots. It can be triggered simply by two robots touching, or a robot bumping into an object on the field. It affects your robot by sparking the main power system, which causes your robot and phone to go into a loop, and you are unable to fix it unless you do a hard reset at the end of the match. Long story short, it disables your robot for the rest of your match!

Of course, when building your robot, you should go through the process of zip tying all your wires down, mounting your electronics on plastic instead of the metal frame, and insulating your wires to reduce static, but those are harder to do and more time-consuming. We do highly recommend that you do all of these above first to minimize your static risk.

But now, there is a simple solution to help reduce static, and just about everyone has them in their home.

Dryer Sheets!

It might sound weird, but let me explain how it works. When you are driving around, your robot wheels are collecting electricity from the floor mats, the beacons, the corner vortex or even other robots. When your robot collects too much static energy, it gets hard to control what happens and when it discharges. It usually discharges when it hits another robot because they also have a lot of electricity built up. When your robot and another robot collide, they have a battle to see who can give off the most static, and the robot who earns more static suffers the consequences.

The spots that collect the most electricity are your side walls if you have plexiglass, or if you place your phone in the middle of your robot.

Dryer sheets are easy to use! All you need to do is take a dryer sheet and wipe down pretty much everything on your robot, from the wheels to the modules, to the side walls, and even the motors and battery. Dryer sheets are an easy way to reduce the static by evening out the amount of positive and negative charge from the robots.

We used these in our last tournament, and we wiped our robot down every other match and found out that it worked for us. We noticed that when we wiped down our robot, the static seemed to be a lot less than for other robots.

Also if you need to reduce static before a match, make sure to place part of your robot that has metal against the wall that has some metal on it. This helps dissipate any charge buildup.

Our team wanted to share this information with other teams because we have noticed that static can be a major problem, and this is an easier solution than making the anti-static spray.

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FTC Tip #10 – Electro Static Discharge Mitigation

FIRST has been conducting electrostatic discharge (ESD) tests with the new Android-based platform for the past year. In general, the new platform tolerates ESD well. According to our engineering contacts at QTI, the test standard IEC/EN 61000-4-2 outlines the procedure that is used for smartphone ESD testing. Most Android smartphones typically adhere to even higher ESD standards, with the ability to withstand a minimum 10 to 12 kV air discharge, and an 8kV contact discharge. Similarly, the electronic modules that are used with the new platform were also designed to tolerate ESD events.

In our testing over the past year, we have found that the new platform tolerates ESD very well. We have used an electrostatic voltmeter and conducted several driving and Van de Graaff generator tests with various test robots. We have conducted discharge tests where the surface voltage on the frame of our robot (as measured with our voltmeter, which has a limit of 25kV) exceeds 25kV without any disruption to the robot. However, we have received credible reports from the field and have seen in our lab testing that ESD events can disrupt the reliable operation of the robot. In our lab testing, the observed number of suspected incidents is low (on the order of 6% or lower), but we do believe that an ESD could occasionally affect the operation of a robot.

Based on our observations over the past year, the risk that a large ESD event can disrupt a robot is relatively low. However ESD is a regular, naturally occurring phenomena and there are steps that teams can take to help reduce this risk even further:

Static Dissipation
• When Teams arrive at the Field, a member of the drive team should touch the metal frame of their robot to the metal frame of the Field perimeter prior to placing the Robot on the Field.
• Doing this should help dissipate any charge buildup that occurs off of the Field.

Robot Construction/Wiring
• Mounting the electronic components of the robot onto non-conductive substrates (such as a sheet of dry plywood, a piece of PVC Type A, or even a polycarbonate sheet) and using non-conductive fasteners (such as zip ties or nylon bolts and nuts) can help reduce the likelihood that an ESD event will disrupt the robot operation.
• Using shorter runs of cables and wires, and keeping the cables and wires off of the frame of the robot (for example, by routing them through PVC Type A pipes or some other non-conductive conduit) can help.
• Covering or cladding the exterior parts of a robot with a non-conductive material reduces the risk that metal parts of the robot will touch a metallic object on the field and cause an ESD event. Wooden bumpers, cloth/tape and other non-conductive coatings can help.

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