Acaia University: Weighing sensor

One of the attributes that makes the Acaia Pearl so wonderful is its responsiveness. Whether it's dosing coffee for a pour over, adding hot water to a brew, or pulling a shot onto a scale, the Pearl reads quickly (20ms) so you don't have to account for the scale lagging behind.

If you have an unstable surface, however, the responsiveness can mean that the scale can have difficulty settling on one value for the weight you've placed on it. The scale isn't actually messing up. If a surface is unstable, then the subtle motion of the surface will result in a small acceleration of the scale and the mass on top of it. Since scales measure force (weight is the force of gravity on an object, as you probably already know), the scale will interpret this motion as a change in the weight it's measuring. Leaning on the counter or placing stacks of saucers or cups down near the weighing area can, if the surface is sufficiently flexible, cause such a situation.

The Pearl, like other electronic scales, takes a rolling average of the output from its weighing sensor. This not only can account for vibrations, but also for the inherent noise in the output of that sensor. Since we use such high-quality components inside the pearl, the time that the scale needs to average to account for noise is shorter – hence the shorter response time. This can render the scale more susceptible to vibration. There's a way to fix this beyond moving to a more stable surface.

Enter the setup menu. Hold down the Power button on startup until you see "SEt" and the scale beeps, then also hold down the T button until the scale beeps and shows "F.0000". Long presses of T change digits, while short presses will change the value of the digits. Enter "0000" to reach the setup menu. Here, short presses of T will cycle through the available settings, while a long press will enter the setting to change it. Cycle to "Filt." This is the weighing filter. This setting can have values from 2 all the way to 128. The default is 16. Higher numbers take a longer rolling average of the scale's sensor and handle vibration better at the cost of slower response time. Smaller numbers average a shorter period of time, rendering the scale more responsive, but more susceptible to vibration.

If you're having a problem with instability of the scale's reading, switch to a higher number.

REMEMBER: The higher you adjust your Filt number, the longer the response time.

We strongly recommend that you use your acaia Pearl on a solid, stable surface for best results. However, if you find yourself forced to use the pearl on a slightly unstable surface, altering the weighing filter can help make the scale more usable.