Electronics Weekly
“Optical-based MAX25205 enables most hand gestures,” according to the company. “The gesture and proximity-sensing sensor features a high level of integration and comes in a 4 x 4mm chip. This gesture solution offers a great complement solution to the voice command, as there are scenarios where voice command is not effective. Another benefit of a gesture solution is that the automotive displays do not become smeared with many finger prints as customers use their touch screens.”
Update: Maxim has now released a full data sheet
It provides an opto-electronic building block with ambient light compensation that, combined with an external microcontroller, allows the detection of hand swipe gestures (left, right, up, and down), finger and hand rotation (clockwise and anti-clockwise) and proximity (3×2 zones).
“We will need an external M0 Arm core, it has the detection algorithm,” Maxim told Electronics Weekly, for example a MAX32630.
Alongside the photodiode array integrated into the chip are 400kHz I2C and 6MHz SPI interfaces – either can be used – and an interface for external LEDs – external power-boosting components are required (see diagram).
The light source’s PWM duty cycle is programmable from 1/16 to 16/16 and, said Maxim, “the LEDs are pulsed on one or more times in a programmable sequence that is repeated for every sample.”
Is the programmable sequence necessary to detect any, or all of, the gestures?
“Yes, it is needed,” Maxim replied to EW.
The part is AEC-Q100 qualified, operates over -40°C to +85°C and at 3.3V (1mA), and comes in a 20pin 4 x 4 x 1.35mm side-wetable optical QFN.
Maxim sees the part being used in controls for central Information displays, doors, roofs, boots, rear seat entertainment and for occupant detection. Outside automotive, consumer and industrial applications such as smart home hubs and thermostats are foreseen.
The MAX25205EVKIT# evaluation kit is available (again, NDA for data), whose web page speaks of “integrated optics with ±20° field-of-view”.
