Slam Stick Product Selection

Slam Stick has been re-branded as enDAQ

This content is for anyone who still owns our original Slam Stick Recorders. These recorders have been significantly upgraded and re-branded as part of the enDAQ platform. Click here for our enDAQ Product Selection Guide.

There are 22 different variants of our Slam Stick recorders, we recognize that it can be difficult sometimes to select the one that's best for your application! If you're not sure, don't hesitate to reach out and ask for help! In general, we recommend the 100g Slam Stick X as our most versatile product due to its wide bandwidth, measurement range, and affordability.

Common Elements of All Slam Sticks

There are many common sensors to every Slam Stick recorder. These sensors include:

• Low power triaxial variable capacitance (DC coupled) accelerometer (either 16g or 200g)
• External temperature
• External pressure
• External humidity
• Internal temperature
• Internal pressure

By external, this specifies a sensor on the membrane/control pad (external graphical sticker). The Slam Stick X and the Slam Stick S have additional accelerometers (piezoelectric and piezoresistive) which are explained below.

More information on the specific sensors and their characteristics are available in this article.

Selection Variables

In order to select the right recorder for your application you need to answer the following questions:

• What type of accelerometer do I need?
• What measurement range do I need?
• How long will it record?
• How harsh is my environment?
• Is cost more important than data quality?

What type of accelerometer do I need?

This is admittedly a complicated question to answer. For more information on accelerometer types and what’s best for your application refer to Midé’s blog post on Accelerometer Selection. But to summarize, there are three types:

• Variable Capacitance: Best for lower frequency (<500 Hz) vibration and some shock if only limited shock information is needed.
• Piezoelectric: Best for vibration with its high sensitivity, but can capture shock as well.  It can experience saturation events when experiencing shock events outside its measurement range however and it is not DC-coupled (can't measure static accelerations or vibrations less than 5 Hz).
• Piezoresistive: Best for high-end shock testing, does not experience saturation from out-of-range events and it is DC coupled (can measure low frequency and static).  Has a higher price point, however.

Our simple harmonic motion calculator includes a dynamic calculator to recommend the right product based upon the inputted frequency and amplitude that is in the calculator.

What measurement range do I need?

The measurement range is inversely proportional to resolution and noise.  Meaning that as you increase the range of accelerations the device can measure, the noise levels increase and the smallest unit of measure also increases.  In general, the 100g piezoelectric (Slam Stick X) accelerometer offers a wide measurement range while also having less than 0.04g in noise.  This is recommended most frequently to users who do not know the range they are looking to measure.  If you buy a unit and within the first test or two realize that you would rather have a wider measurement range or better resolution, we can exchange the unit for no cost.

More information on the specific sensors and their characteristics are available in this article.

How long do I need to record for?

Each unit has a standard storage of 1 GB (Slam Stick C) or 2 GB (in the X and S); but they can all be upgraded to 8GB of storage.  Each 1GB of storage can record roughly 500 million data points so the sampling rate chosen for your test will dictate how much storage you need.  For example, if you are sampling at only 100 Hz in one accelerometer (300 Hz total for 3 axes) 1 GB of storage will be able to record over 19 days of continuous measurement.  But if you were sampling at 20 kHz in all three axes the 1 GB of storage will "only" record just over 2 hours of continuous measurement.

Aluminum enclosure units, due to the larger size to accommodate the piezoresistive accelerometers, also have a slightly increased battery capacity of 250 mAh vs the 200 mAh battery in the polycarbonate enclosure units. To try out different sampling rate configurations with all the different sensors, you can use our battery life calculator to estimate storage and battery consumption.

How harsh is the environment?

The Slam Stick comes in two enclosure options: aluminum 7075 and polycarbonate.  The electronics are the exact same in each unit but the enclosure material and the manufacturing have two significant impacts:

• Stiffness: A Slam Stick is, in effect, an accelerometer.  As such, an accelerometer's own internal resonance will limit the frequency range it can accurately measure before its own resonance starts influencing and amplifying the vibration in the environment and becomes invalid.  The aluminum enclosure is much stiffer and therefore increases the bandwidth from up to 1,000 Hz in the polycarbonate enclosure to 2,000 Hz in the aluminum enclosure.
• Robustness: The aluminum enclosure is obviously more robust than the polycarbonate enclosure.  If your device will be handled repeatedly with frequent mounting and dismounting and potentially subjected to occasional direct impacts, the aluminum enclosure may be the better option.

For more information on the different enclosures are available in this article.

Is cost more important than data quality?

We have a range of products that have a lot of overlap in general functionality.  But as the above discussions explained, the differences matter when it comes to the type of data recorded. Often though, with better quality comes higher costs and prices.  We aim to make all our products affordable yet of high quality, but within our product line there are still some tradeoffs.  If cost is a primary driver for you or your organization we recommend the Slam Stick C model or to check out some lower priced competitors discussed here. We are developing a new, lower-cost product line that can help address some of you that are limited by budget.  That should be available in mid-2019; but that line will have internal sensors with some limited performance capabilities compared to our higher-end models.

Table of Products

The above discussion can help simplify the decision points but it still results in 22 different variants of products to choose between with different pricing and specifications. A reduced table is included below with a more extensive table available here in Excel.