Anti-Collision and G-Force Detection in Standing Desks

Once a new and exotic feature on pricier models, anti-collision detection can now be found on even some of the less expensive standing desks on the market. In this primer we’re going to cover three questions:

1) What is anti-collision detection?

2) How valuable is it?

3) How well does it work in real world conditions?

What is Anti-Collision Detection: The Basic Rundown

The obvious reason for detecting a collision between your desk and some object during height adjustment is to avoid costly damage to either. Examples of collision objects include door knobs, low shelves, trash bins, file cabinets, and armchairs.

The circuitry typically works by detecting a sudden spike in current draw from the motors in the desk leg’s lifting columns. So if the desk hits a soft object, like a cushy chair back that leans easily, the current spike won’t likely be detected. But if the desk runs into a door knob it should immediately stop and back off an inch or so, before any major damage would be done.

We can dispense with one myth right up front—that anti-collision circuitry can detect a small child or animal—they are way too squishy to produce that hard spike in current draw. We’ve never heard of a small child or animal being injured by a standing desk on the move, but some companies (from our experience, usually Asian) make the specious marketing claim that their desks are designed to avoid such injury. That’s neither true nor relevant. (A few desks are now coming equipped with a “G-Force sensor” that has a better chance of detecting a child or large dog trapped under the desk by virtue of it starting to tip over; see below.)

Do You Really Need Anti-Collision Detection?

How much value anti-collision adds to the standing desk experience is obviously very subjective, but for some people it may be a non-essential feature. A “nice-to-have” versus “need-to-have.” There a couple of big exceptions, though; read on.

Unless you have a highly variable environment, such as one where you have your desk on caster wheels and change location within the office frequently, it’s most likely you have cleared all the object collision potential around your workstation when you first set your desk up.

It also depends on what your desk is likely to crash into. If a door knob, that could cause some major equipment damage. If a soft rubber trash bin, probably not of significant concern unless running into it causes the entire desk to tilt over.

There is one scenario, however, in which our standing desk experts believe anti-collision is an absolute necessity, and that’s with certain very commonly sold standing desks, usually made in China, that don’t comply with UL standards for the USA. In Asia or Europe, UL (Underwriters Laboratories) testing standards do not specify that the user of a standing desk must keep their finger on the up or down button the entire time the desk is in motion. (Note: just having a UL symbol on the power supply brick is not the same thing as having a UL 962 certification (for “Household and Commercial Furnishings”) on the entire desk system. American-made standing desks generally do have this more meaningful UL certification.

In our more litigious American society, UL standards preclude “fire-and-forget” controller designs; they want users to keep their finger on the button as long as the motors are energized. Notable exceptions include the American-made iMovR Lander Desk and Lander Lite desks, which come with a smartphone app that lets users opt-out of that UL limitation by agreeing to a “click-wrap” liability waiver. That’s the proper way to do it.

How Well Does Anti-Collision Detection Work?

The effectiveness of anti-collision detection varies wildly between manufacturers, between desk lines, and even depends on the size of desktop and the distribution of weight relative to the lifting columns and crossbar underneath.

As a broad statement, the collision detectors that do tend to work better when the desk is being raised than when it is being lowered, based on our observations from testing dozens and dozens of standing desks in the lab over the years. This may simply be due to the fact that an ascending desk consumes a lot more current as compared to a descending desk, so the current spike is likely to be larger.

What usually happens when a collision fails to be detected is that one side of the desk “high sides” over the obstacle, until you take your hand off the controller. It’s pretty obvious when this is happening so it’s not a big deal to move your finger to the other button and reverse course. In most cases this isn’t going to damage anything too severely, although left unattended, (i.e. if your desk has one of those fire-and-forget, Asian-sourced controllers), you could find your monitor, laptop and other desktop objects on the floor by the time you can stop the motion.

An annoying thing we’ve found with certain desks with larger desktops, typically 71” and up, is that they can falsely trigger the collision detector due to bowing in the desktop. Especially if loaded up with lots of monitors and equipment in the center of the desk, and especially if the desk’s feet are situated on carpet, it’s possible for the desktop to bow in the middle, imposing excessive side loads on the lifting columns. So in the middle of raising your desk, the anti-collision feature kicks in and stops the desk from moving up. Higher quality controllers will have a sensitivity adjustment on the handset that you can change to overcome this issue if you encounter it. Cheaper import desks often do not have a sensitivity adjustment.

There is a new kid in town, though, with the advent of new brushless motor technology in desks like the iMovR Jaxson. Brushless motors have no carbon commutators brushing against the armature of the motor to create “electrical arcing.” Arcing generates signal noise that can interfere with the sensitivity of collision detection circuitry. While “completely flawless” would be too strong a word to use for any collision detection circuit, the new brushless motors come closer to this aspirational goal than any other we’ve ever tested in our labs. Read more about this in our blog article on How Brushless DC Motor Technology Is Bound To Entirely Disrupt the Standing Desk Industry.

Does Having a G-Force Sensor Help?

As a back-stop to any failure of the anti-collision detection circuitry a few desks have started appearing on the market that feature a “G-Force” sensor that can detect if your desk is starting to tilt over because it has run into an obstruction below. This “belt-and-suspenders” approach to incorporating safety measures into a standing desk is akin to how Volvo designs their cars to achieve that 5-star safety rating.

If you’re concerned with small children playing with your desk while you’re away, worried less about them getting trapped underneath than just breaking something, the G-Force Sensor is a great thing to have. That way if the desk starts to tilt over because of an obstacle (hopefully not a younger sibling) the G-Force sensor will stop the desk before it can topple over. The first standup desks we reviewed that include a G-Force sensor include the iMovR ZipDesk.

To find out how well a particular desk’s anti-collision feature works, or if it even has one, be sure to check here first whether we’ve published a full lab-test review of that particular model.