Before getting into the details of this new device I first want to highlight that although this eye tracker can be used as a computer access solution for someone with a disability (it already works with Optikey and Project IRIS), it is not being marketed as such. What this means in practice is that it may not provide the reliability that their much costlier Assistive Technology (AT) eye trackers such as the Tobii PC Eye Mini do. So if eye tracking is your only means of communication or computer access and you have the funds I would recommend spending that extra money. That said, many people don’t have the funds or perhaps they have other more robust means of computer access and just want to use eye tracking for specific tasks like creating music or gaming. For those people the Tracker 4 C is really good news as it packs a lot into the €159 price tag and overcomes many of the weaknesses of its predecessor the Tobii Eye X. The big improvement over the Tobii Eye X is the inclusion of the EyeChip. The EyeChip which was previously only included in the much more expensive range of Tobii AT eye trackers takes care of most of the data processing before sending it on to the computer. The result of this is much less data is being passed to the computer from the eyetracker (100KB/S compared to 20MB/S) and a much lower CPU (Central Processing Unit) load (1% compared to 10%). This allows it to work over an older USB 2 connection and means most (even budget) computers should have no problem running this device (unlike the Eye X which required a high end PC).
All this must have come as some compromise in performance right? Wrong. The Tracker 4C actually beats the Eye X in almost every category. Frequency has risen from 70Hz to 90Hz, slightly longer operating distance is possible .95m, and the max screen size has increased by 3” to 30”. This last stat could be the deciding factor that convinces Tobii PC Eye Mini users to buy the Tracker 4 C as a secondary device as the Mini only works with a max screen size of 19”. The Tracker 4 C also offers head tracking but as I haven’t tested the device I’m unsure of how this works or of it is something that could be utilised as AT. Watch this space, the Tracker 4 C is on our shopping list and I’ll post an update as soon as we get to test whether it’s as impressive in real life as it seems on paper.
The table below compares specs for all Tobii’s current range of consumer eye trackers. In some areas where information was not available I have added a question mark and if appropriate a speculation. I am open to correction.
|Eye Tracker Models||Tobii Eye Tracker 4C||Tobii EyeX*||Tobii PC Eye Explore||Tobii PC Eye Mini|
|Size||17 x 15 x 335 mm
(0.66 x 0.6 x 13.1 in)
|20 x 15 x 318 mm
(0.8 x 0.6 x 12.5 in)
|20 x 15 x 318 mm
(0.8 x 0.6 x 12.5 in)
|170 mm × 18 mm × 13 mm
6.69“ × 0.71“ × 0.51“
|Weight||91 grams||91 grams||69 grams||59 grams|
|Max Screen Size||27 inches with 16:9 Aspect Ratio
30 inches with 21:9 Aspect Ratio
|27 inches||27 inches||19 Inches|
|Operating Distance||20 – 37″ / 50 – 95 cm||20 – 35″ / 50 – 90 cm||18-32 “/ 45-80 cm||45 cm – 80 cm 18” – 32″|
|Track Box Dimensions||16 x 12″ / 40 x 30 cm at 29.5″ / 75 cm||16 x 12″ / 40 x 30 cm at 29.5″ / 75 cm||19 x 15” / 48 x 39cm||>35 cm × 30 cm ellipse
>13.4” × 11.8”
|Connectivity||USB 2.0 (integrated cord, USB 2.0 BC 1.2)||USB 3.0 (separate cord)||USB 3.0||USB 2.0|
|USB Cable Length||80 cm||180 cm||180 cm||(short, extension needed in some situations)|
|Head Tracking||Yes (not powered by EyeChip)||No||No||No|
|OS Compatibility||Windows 7, 8.1 and 10 (64-bit only)||Windows 7, 8.1 and 10 (64-bit only)||Windows 7, 8.1 and 10 (64-bit only)||Windows 7 Windows 8.1 Windows 10|
|CPU Load||1%*||10%||10%||? (unconfirmed but similar to Tracker 4 C)|
|Power Consumption||1.5 Watt||4.5 Watt||? (unconfirmed but suspect same as Eye X)||1.5 Watt|
|USB Data Transfer Rate||100KB/s||20MB/s||? (unconfirmed but suspect same as Eye X)||? (unconfirmed but similar to Tracker 4 C)|
|Frequency||90 Hz||70 Hz||55 Hz||60Hz|
|Illuminators||Near Infrared (NIR 850nm) Only||Backlight Assisted Near Infrared
(NIR 850nm + red light (650nm))
|? (unconfirmed but suspect same as Eye X)||?|
|Tracking Population||97%||95%||? (unconfirmed but suspect same as Eye X)||?|
|Additional Software||Tobii Eye Tracking Core Software||Tobii Eye Tracking Core Software||Gaze Point (mouse emulation software)||Windows Control|
* The specs given here are taken from those listed on https://help.tobii.com/hc/en-us/articles/212814329-What-s-the-difference-between-Tobii-Eye-Tracker-4C-and-Tobii-EyeX- accessed 08/03/2017. Because the weight listed is 91 grams I suspect these specs are for the first generation Tobii Eye X (as it weighs 91 grams, the more recent Eye X weighs 69 Grams). The current Eye X specs are probably similar to the PC Eye Explore but I cannot confirm this.