Sensor and Performance

The Ploopy Mouse is equipped with the PixArt PMW3360. According to specifications, the 3360 is capable of up to 12,000 CPI, as well as a maximum tracking speed of 250 IPS, which equals 6.35 m/s. Out of the box, three pre-defined CPI steps are available: 1200, 1600, and 2400.

CPI Accuracy

"CPI" (short for counts per inch) describes the number of counts registered by the mouse if it is moved exactly an inch. There are several factors (firmware, mounting height of the sensor not meeting specifications, mouse feet thickness, mousing surface, among others) which may contribute to nominal CPI not matching actual CPI. It is impossible to always achieve a perfect match, but ideally, nominal and actual CPI should differ as little as possible. In this test, I'm determining whether this is the case or not. However, please keep in mind that said variance will still differ from unit to unit, so your mileage may vary.


I've restricted my testing to the four most common CPI steps, which are 400, 800, 1600, and 3200. As you can see, deviation is consistent and minor, which is a very good result.

Motion Delay

"Motion delay" encompasses all kinds of sensor lag. Any further sources of input delay will not be recorded in this test. The main thing I'll be looking for in this test is sensor smoothing, which describes an averaging of motion data across several capture frames in order to reduce jitter at higher CPI values, increasing motion delay along with it. The goal here is to have as little smoothing as possible. As there is no way to accurately measure motion delay absolutely, it can only be done by comparison with a control subject that has been determined to have the lowest possible motion delay. In this case, the control subject is a G403, whose 3366 has no visible smoothing across the entire CPI range. Note that the G403 is moved first and thus receives a slight head start.


First, I'm looking at two xCounts plots—generated at 1600 and 3200 CPI—to quickly gauge whether there is any smoothing, which would be indicated by any visible "kinks." What is immediately noticeable here is the fact that xCounts are capped at +127. In fact, both xCounts and yCounts are restricted to +127 to -127 respectively, the implications of which will be explored in further detail down below and on the next page. As an aside, SPI timing jitter is fairly high.


In order to determine motion delay, I'm looking at xSum plots generated at 1600 and 3200 CPI. The line further to the left denotes the sensor with less motion delay. At 1600 CPI, there is no difference in motion delay. At 3200 CPI, a motion delay differential of roughly 4 ms can be seen. This is in line with what to expect from a 3360, which has 32 frames of smoothing at and above 2100 CPI with SROM 4 or earlier.

Speed-related Accuracy Variance (SRAV)

What people typically mean when they talk about "acceleration" is speed-related accuracy variance (or short SRAV). It's not about the mouse having a set amount of inherent positive or negative acceleration, but about the cursor not traveling the same distance if the mouse is moved the same physical distance at different speeds. The easiest way to test this is by comparison with a control subject that is known to have very low SRAV, which in this case is the G403. As you can see from the plot, no displacement between the two cursor paths can be observed, which confirms that SRAV is very low.

Perfect Control Speed

Perfect Control Speed (or PCS for short) is the maximum speed up to which the mouse and its sensor can be moved without the sensor malfunctioning in any way. As mentioned above, the Ploopy Mouse is capped at x and yCounts of +127 to -127. Any counts exceeding that limit will be clipped. The PCS is a function of these limits, which is why it is inversely proportional to the set CPI. In other words, the higher the CPI, the lower the PCS will be.


At 400 CPI, the theoretical PCS sits at around 8 m/s, which is in excess of the specifications of the 3360 anyway and virtually impossible to reach in practice. At 800 CPI, the theoretical PCS is 4 m/s, and we can see that motion gets clipped around that mark. At 1600 CPI, it's very easy to see the clipping at 2 m/s. Due to linear scaling, tracking ceases entirely at maximum CPI.

Polling Rate Stability

I've only tested 1000 Hz, which looks and performs fine. Lower polling rates are theoretically possible, though I haven't tested them.

Paint Test

This test is used to indicate any potential issues with angle snapping (non-native straightening of linear motion) and jitter, along with any sensor lens rattle. As you can see, no issues with angle snapping can be observed. No jitter is visible at 400, 800, and 1600 CPI, and the smoothing kicking in at 3200 CPI gets rid of any jitter there theoretically may be. Lastly, there is no sensor lens movement.

Lift-off Distance

The Ploopy Mouse does not offer any LOD adjustment. By default, the sensor does not track at a height of 1 DVD (<1.2 mm). Keep in mind that LOD may vary slightly depending on the mousing surface (pad) it is being used on.

Click Latency

Since mechanical switches are being used for the buttons in most computer mice, debouncing is required in order to avoid unintended double clicks. Debouncing typically adds a delay (along with any potential processing delay), which shall be referred to as click latency. As there is no way to measure said delay directly, it has to be done by comparing it to a control subject, which in this case is the Logitech G203. Using the default QMK firmware, click latency has been measured to be roughly +6.5 ms when compared to the SteelSeries Ikari, which is considered as the baseline with 0 ms, with standard deviation being 0.66 ms. Please keep in mind that the measured value is not the absolute click latency. Comparison data comes from this thread as well as my own testing, using qsxcv's program.