Transcript

Testing the Bolt Against Static Discharge

We’re testing if the Bolt is safe from the user, who may have a static charge on their body when they touch the Bolt. If the static zap happens, we want to make sure the Bolt is protected from that.

There’s a standard for that. We’re using IEC 61004-2 as our guide, and that calls for a level four testing, which is a test pulse at 15 KV near the Bolt on a horizontal coupling plane.

Test Setup

We have our official horizontal coupling plane, which is a conductive sheet, and that’s connected to ground with the official ground strap with two 470 kilometer resistors in series. That provides a little bit of a slower discharge, so that when we pulse the plate, the energy stays near the Bolt for a longer amount of time.

The rise time on the pulses from the ESD gun are in the nanosecond range, and so we want to make sure that the charge builds up on the plate before it dissipates into ground. The test calls for those resistors in series to prolong the amount of field that the Bolt sees.

The test calls for zapping the plate at various points around the edge near the Bolt, and also attempting to discharge on the Bolt itself. We have our ESD gun, which applies 15 KV in the positive and negative direction with alternate polarity, and we’re gonna give it 10 test pulses at various points on the edge of the plate and near the Bolt.

Monitoring the Bolt During the Test

The goal of this test is to make sure the Bolt survives the test with no loss of memory. We have a live connection to the Bolt right now. We can see it running one channel of voltage into channel one to power the Bolt. The other two channels are grounded so that we can see if we have any ESD influence on the measurement. We’re using wifi to connect the Bolt to Provision here.

Applying Test Pulses

I’m gonna apply test pulses on the edge of the plate. You can see and hear the pulse. And as I approach the plate, the arc finally jumps the distance and discharges.

Now I’m gonna attempt to pulse the Bolt itself, but the Bolt is so well-insulated that it’s not really possible to get a 15 KV pulse to go all the way inside the electronics of the Bolt.

We can pulse around the voltage connectors, conductors, and here it’s really just jumping around the surface of the insulation and then hitting the plate.

We can see that our count timer for the test misoperated even though it’s not actually connected to the horizontal coupling plane, but it’s enough of a discharge to interfere with that clock.

Post-Test Verification

That completes the test. Now let’s power cycle the Bolt. We can see that the Bolt is still recording given the LED operation. But I’m going to power cycle the Bolt and make sure that it comes back up correctly.

I’ll remove the voltage cable and the Bolt will continue to run on its super capacitors for a bit, and we’re gonna let that discharge.

I’m gonna apply power to the Bolt and let the Bolt boot back up. You can see the Bolt go through its boot sequence with the LEDs. And now the Bolt is back on the wifi network, and I will reconnect to the Bolt with Provision.

We have our waveforms back, and the Bolt is operating normally. The Bolt is safe from the user given that it survived the IC 61004-2 ESD discharge test.