Troubleshooting


Some common problems that require simple fixes are presented below for troubleshooting. If you experience an issue that is not covered here or if the suggested actions do not resolve the problem, please contact Midé to receive assistance, we're here to help!  The following section provides links to user guides on various troubleshooting related topics, which is then followed by another list of common questions and issues.


Troubleshooting - Guides


Common Questions

Note

Many common failure modes can be resolved by resetting the device. This is achieved by holding down the button for 10 seconds. The initial button press/hold will cause the LEDs to indicate current battery life, and then they should turn off. Continue holding down the button though for another 5 seconds. At that time all LEDs will turn on until you release the button. This will not delete any data on the unit or change the configuration, it just reboots it.

What happens when a piezoelectric accelerometer experiences an acceleration level outside its measurement range?

This can cause the charge amplifier within the accelerometer to saturate which will result in a logarithmic decay following the event.  Our blog on piezoelectric accelerometers goes into more detail on why this happens.  Sometimes this occurs because of high-frequency vibrations which can excite resonances inside the accelerometer.  In this case, you may need some mechanical damping.  The piezoresistive accelerometers are the best for shock testing however as they do not experience this issue and even have internal gas damping to prevent resonance issues.  PCB Piezotronics also has a nice application note with more information on this "issue" with piezoelectric accelerometers.

Why does the Slam Stick measure +1g at rest, shouldn't it be -1g?

This is a good question and caused some initial panic internally at Mide when we first introduced units with the DC accelerometer. It's very counter-intuitive at first but let's try and explain it! The short answer is that accelerometers measure a deviation in acceleration from free-fall. So at rest, there is +1g acting upward to keep it still and overcome Earth's gravitational acceleration downward.

Accelerometers have a suspended proof mass and they measure the strain on springs holding that proof mass. When the device is on your desk the proof mass isn't perfectly centered so it can see that shift in location. When in free fall the proof mass becomes centered and therefore it measures 0g acceleration... at least that's how I've explained it to myself. There's a bit more formal of an answer related to Einstein's "equivalence principle." Below is an excerpt from Wikipedia that has a bit more information.

An accelerometer measures  proper acceleration, which is the acceleration it experiences relative to freefall and is the acceleration felt by people and objects.[2] Put another way, at any point in spacetime the equivalence principle guarantees the existence of a local inertial frame, and an accelerometer measures the acceleration relative to that frame.[3] Such accelerations are popularly denoted g-force; i.e., in comparison to standard gravity.

An accelerometer at rest relative to the Earth's surface will indicate approximately 1 g  upwards, because any point on the Earth's surface is accelerating upwards relative to the local inertial frame (the frame of a freely falling object near the surface). To obtain the acceleration due to motion with respect to the Earth, this "gravity offset" must be subtracted and corrections made for effects caused by the Earth's rotation relative to the inertial frame.

The reason for the appearance of a gravitational offset is Einstein's  equivalence principle,[4] which states that the effects of gravity on an object are indistinguishable from acceleration. When held fixed in a gravitational field by, for example, applying a ground reaction force or an equivalent upward thrust, the reference frame for an accelerometer (its own casing) accelerates upwards with respect to a free-falling reference frame. The effects of this acceleration are indistinguishable from any other acceleration experienced by the instrument, so that an accelerometer cannot detect the difference between sitting in a rocket on the launch pad, and being in the same rocket in deep space while it uses its engines to accelerate at 1 g. For similar reasons, an accelerometer will read zero during any type of free fall. This includes use in a coasting spaceship in deep space far from any mass, a spaceship orbiting the Earth, an airplane in a parabolic "zero-g" arc, or any free-fall in vacuum. Another example is free-fall at a sufficiently high altitude that atmospheric effects can be neglected.

The Device Appears “Frozen” and is Unresponsive

If the unit is not responding to button presses and/or displays a constant LED indication (even when unplugged from power) the software is hanging up.  Try a hard reset by holding down the button for 10 seconds. If this doesn’t resolve the issue, contact Midé for assistance.

No LED Activity after Pressing the Button

This may be due to the battery being depleted and therefore the device requires charging.  Also try a hard reset by holding down the button for 10 seconds. If this doesn’t resolve the issue, contact Midé for assistance.

There are No New Recording Files on the Device

This question comes up often.  Remember the device will never start recording or looking for a trigger until the button is pressed regardless of the trigger configuration. Another possible explanation is that the trigger conditions were never met.  Also, check to ensure there is storage space available on the device (it appears as a standard USB flash drive).  The battery could have also died that prevented the unit from recording.  Finally, make sure to read the Recording File Naming & File Structure Section to understand how files are named and stored on the device.  If the problem persists, contact Midé for assistance.

Data File is Corrupted or Does Not Display Data (0 KB file)

The Slam Stick may have suddenly run out of power and therefore did not close out the file properly.  This can happen rarely due to battery dips; but can also happen from sudden and extreme impact events directly to the device, water damage, and rapid temperature swings.  See the SD Card & Memory Management Section for assistance on potentially recovering the file. Midé can also occasionally recover data files that fail in this manner.

When the Device Initially Plugs into Power, only the red LED Flashes

This indicates an error code.  Take note of the number of times the LED flashes and contact Midé for assistance.

The Device does not appear in “My Computer” when Connected

Wait several moments to ensure that the computer isn’t first trying to “recognize” the device. Then try to ensure that the USB cable is properly connected, the LED should turn on when connected to the computer or power. Also, this can happen when the device is still in the recording or trigger mode. Another possibility is that your computer’s security software is blocking the device, please try a different computer and/or contact your IT department.

Slam Stick Lab Software does not Run

This is likely due to a security issue; you may have to contact your IT department.  Otherwise double check that you are running the appropriate version for your operating system (there is a 64-bit and 32-bit version).  Currently, the Slam Stick Lab only runs on Windows computers.

I Work for the Navy and I need the Correct Configuration File

There is a specific configuration file recommended by NAVAIR for testing on F/A-18s that disables all sensors besides the pressure channels.  It is attached here.

Microsoft Windows is Prompting to Scan and Fix the Slam Stick Drive

Some Windows versions present this dialog for some drives not formatted by Windows.  This message is harmless; the user may either proceed with or cancel the scan.

Note

Do not use disk utilities to perform “bad sector” tests on the device. Not only is this type of test not suitable for Flash media, but the utility may also incorrectly detect “bad” sectors on the device due to the special mechanism the device uses to provide dynamic data via virtual files (such as the clock setting and device information).