ST AEK-SNS-2TOFM1 Bedienungsanleitung

Introduction

The AEK-SNS-2TOFM1 evaluation board offers an innovative approach based on Time-of-Flight (ToF) sensors for car power

liftgate applications.

This board represents a more cost-effective and reliable solution compared to the standard "kick under the bumper" solution.

The distance among the on-board sensors has been specifically designed for placement under the car bumper.

The kick gesture is replaced with a more unequivocal foot gesture interpreted by a finite state machine built in the

microcontroller firmware.

The board is designed as a small sensor hub ECU able to retrieve and process real-time sensor data to detect a gesture

performed under the two sensors. Moreover, you can control the board through an external domain controller via a CAN or a

serial interface.

Figure 1. AEK-SNS-2TOFM1 evaluation board

Warning: The AEK-SNS-2TOFM1 is an evaluation tool for R&D laboratory use only. It is not intended to be used

inside a vehicle.

Getting started with the AEK-SNS-2TOFM1 evaluation board for car power

liftgate applications

UM3006

User manual

UM3006 - Rev 1 - May 2022

For further information contact your local STMicroelectronics sales office. www.st.com

1Getting started

1.1 Hardware overview

The following figure shows the AEK-SNS-2TOFM1 top components:

1. 12 V DC-DC connector

2. SPC582B60E1 Chorus 1M automotive-grade microcontroller

3. Successful detection LEDs

4. JTAG connector for microcontroller programming

5. CAN connector

6. Serial connector

Figure 2. AEK-SNS-2TOFM1 components (top view)

The following figure shows the AEK-SNS-2TOFM1 bottom components:

1. VL53L1X Time-of-Flight ranging sensor based on ST FlightSense technology

Figure 3. AEK-SNS-2TOFM1 components (bottom view)

The board hosts the SPC582B60E1 automotive microcontroller that belongs to the Chorus family, with a high

performance e200z2 single core 32-bit CPU running at 80 MHz clock, a 1088 KB flash memory, and a 96 KB

SRAM in a compact eTQFP64 package. The microcontroller monitors and controls the two ToF sensors to detect

the foot gesture.

The communication between the microcontroller and the ToF sensors is implemented via SPI. The microcontroller

controls the LEDs on the board top side through two dedicated GPIOs.

The AEK-SNS-2TOFM1 can be remotely controlled through a central ECU via a CAN or a serial interface. For this

reason, a CAN connector and a serial connector are present on the board.

UM3006

Getting started

UM3006 - Rev 1 page 2/38

1.2 Software overview

The AEK-SNS-2TOFM1 board contains a preloaded demonstration firmware. It is ready to be tested.

If you have modified the flash memory code and you want to reinstall the original version, use the SPC5-UDESTK

programmer plugged on the JTAG connector. The source code is included in AutoDevKit 1.6.1 (or higher). Among

other demos, you can find one called “SPC582Bxx_RLA AEK_SNS_2TOFM1_1M_with_CAN_for_footdetection-

Trunk System Control”.

For the detailed upload procedure, refer to Section 3.7

The above-mentioned demo purpose is to detect a specific foot/hand gesture and to inform a domain controller

via a CAN message that the successful detection event has occurred.

The gesture consists in a foot/hand movement from the left to the right and vice versa.

Figure 4. Gesture recognition pattern

The recognition process starts when the gesture crosses at least one of the photon beams emitted by the two ToF

sensors.

The algorithm implemented requires that the gesture has to be performed in one second maximum. If the gesture

is not detected, wait one second before repeating it. When the correct movement is detected, the two on-board

LEDs blink three times.

To work correctly, the demo requires the board to be placed at 132 mm height. Otherwise, the two sensors are

not properly configured during the power-up calibration phase. As soon as the board is turned on, and the system

is correctly initialized, the two on-board LEDs turn on. The two sensors detect the movement of the foot/hand for

distances between 0 and 120 mm. The demo can also receive external CAN messages to turn the ToF sensors

on/off. The detected_foot() is used to implement the gesture algorithm.

When performing the tests outdoor, ensure placing the AEK-SNS-2TOFM1 board as shown in the following figure,

to make the sensor photon beams fall within the car shadow cone.

Figure 5. Board placement

ToF

Car shadow

UM3006

Software overview

UM3006 - Rev 1 page 3/38

1.2.1 Gesture recognition

The gesture consists in crossing the detection base (that is, the distance between the two ToF sensors) in both

directions, as shown in the figure below.

Figure 6. Gesture on the detection base

The algorithm is based on the idea that the foot detection state can have one of the following values:

•0: not detected

• 1: detected by sensor 1 (left-hand side)

• 2: detected by sensor 2 (right-hand side)

Figure 7. Detection system states

A gesture can be represented through a sequence of states. The sequence that represents the gesture of the

figure above is: 0,1,0,2,0,2,0,1,0. The sequence 0,2,0,1,0,1,0,2,0 is also admitted as we want the gesture to start

in the opposite direction, too. The central zeros in the sequence are necessary because a complete crossing of

the detection base is desired. For example, the first admitted sequence is shown in the figure below.

UM3006

Software overview

UM3006 - Rev 1 page 4/38

Figure 8. Accepted sequence

The detect_foot () function, cyclically called by the microcontroller, implements the algorithm.

The foot detection functions can be divided in:

1. System State Detect that detects the state of the system:

– if sensor 1 detects an object, the state becomes 1

– if sensor 2 detects an object, the state becomes 2

– if there is no detection, the state becomes 0

– if both sensors detect something, the state becomes 3

The last value means that there is a fixed object under the trunk (for example, a stone).

2. State Sequence Update that updates the gesture sequence if the state changes.

3. State Sequence Check that compares the detected sequence with those admitted as soon as the

detected pattern reaches a length equal to the SEQ LEN. If there is a match, the function sets a, which is a

global variable representing the achieved foot detection, to 1.

4. System Reset: if the sequence reaches a length equal to the SEQ LEN and there is no match, or a RESET

TIME has elapsed, the system resets and restarts the detection mode.

UM3006

Software overview

UM3006 - Rev 1 page 5/38

2Basic concepts on FlightSense ToF sensors and their usage in

AutoDevKit

2.1 Overview of the FlightSense ToF sensor principle

The Time-of-Flight is a method for measuring the distance between a sensor and an object. It is based on the

time difference between the emission of a light signal and its return to the sensor, after being reflected by the

object.

Figure 9. ToF principle

According to the ToF principle, the sensors used in the AEK-SNS-2TOFM1 embed:

• an emitter that is a vertical cavity surface emitting laser (VCSEL);

• a receiver that is an array of single photon avalanche diodes (SPADs). The photons emitted by the laser

reflect on the target and trigger avalanches when coming back to the SPAD.

The ToF sensor also features a region of interest (ROI) that can be selected. It can be reduced from its nominal

27° field of view (FoV) to 15° with the only condition of having an array of at least 4x4 SPADs.

UM3006

Basic concepts on FlightSense ToF sensors and their usage in AutoDevKit

UM3006 - Rev 1 page 6/38

Figure 10. ToF sensor system FoV: receiver cone at 27°

The ROI selection is used to position the reduced sensing area at a selected place on the SPAD array to detect

and measure the distance of the specified area of interest of the external scene. Instead, the reduced FoV uses a

reduced number of SPADs for the ROI sensing area to limit the viewing angle of the sensor device.

For more information on the VL53L1X, refer to the datasheet, whereas, for more information about the

programmable region of interest (ROI), refer to AN5191.

2.2 VL53L1X

The VL53L1X is a state-of-the-art, Time-of-Flight (ToF), laser-ranging sensor, enhancing the ST FlightSense

product family. It is the fastest miniature ToF sensor on the market. It features an accurate ranging up to 4 m and

fast ranging frequency up to 50 Hz.

Housed in a miniature and reflowable package, it integrates:

• a SPAD receiving array;

• a 940 nm invisible Class1 laser emitter;

• physical infrared filters;

• optics to achieve the best ranging performance in various ambient lighting conditions with a range of cover

glass options.

Unlike conventional IR sensors, the VL53L1X uses ST latest generation ToF technology, which allows absolute

distance measurement independently of the target color and reflectance.

You can also program the size of the ROI on the receiving array, allowing the sensor FoV to be reduced.

Figure 11. VL53L1X ToF

UM3006

VL53L1X

UM3006 - Rev 1 page 7/38

2.2.1 ToF sensor characteristics

The AEK-SNS-2TOFM1 sensor characteristics are:

• a laser wavelength of 950 nm ± 30 nm;

• invisible laser (Class 1);

• invisible laser radiation;

• a maximum laser power emission of 25 mW.

2.2.2 Laser safety considerations

The AEK-SNS-2TOFM1 ToF sensors contain a laser emitter and the corresponding drive circuitry.

The laser output is designed to remain within Class 1 laser safety limits under all reasonable foreseeable

conditions, including single faults, in compliance with the IEC 60825-1:2014 (third edition).

The laser output remains within Class 1 limits as long as you use the STMicroelectronics recommended device

settings and respect the operating conditions specified in the data sheet.

The laser output power must not be increased and no optics should be used with the intention of focusing the

laser beam.

Figure 12. Class 1 laser product label

2.2.3 VL53L1X-SATEL industrial-grade ToF evaluation board

The AEK-SNS-2TOFM1 development is based on the hardware and software provided to evaluate the ToF

sensors. The evaluation board used is the VL53L1X-SATEL. For this board, we have already implemented an

AutoDevKit component named AEK_SNS_VL53L1X.

The demo software for the AEK-SNS-2TOFM1 has been developed by reusing the APIs already available for

the VL53L1X-SATEL. In turn, the VL53L1X-SATEL drivers have been imported from the STM32 drivers just by

customizing the hardware abstraction layer (HAL) calls for the SPC58 family microcontrollers.

The VL53L1X-SATEL breakout compact board can be used for easy integration.

Thanks to the voltage regulator and level shifters, this board can be used in any application with a 2.8 V to 5 V

supply.

UM3006

VL53L1X

UM3006 - Rev 1 page 8/38

Figure 13. VL53L1X-SATEL top and bottom views

The embedded VL53L1X ToF sensor uses the I²C protocol for communication.

The I²C bus on the VL53L1X has a maximum speed of 400 kbits/s and uses a default device address (0x52).

You can connect the VL53L1X-SATEL to an MCU board through different connection types, as shown in the figure

below.

Figure 14. VL53L1X-SATEL connection types

UM3006

VL53L1X

UM3006 - Rev 1 page 9/38

2.2.4 Power up and boot sequence

The ToF sensor has two different options for the power-up and boot sequence:

•Option 1: the XSHUT pin is connected and controlled from the host. This option optimizes the power

consumption as the sensor can be completely powered off when not used, and then woken-up again. The

hardware standby mode is defined as the period when the power supply is present and the XSHUT is low.

Figure 15. Power up and boot sequence

XShut

System state Power off HW standby SW standbyBoot

Power supply

•Option 2: the host does not control the XSHUT pin, which is tied to the power supply through a pull-up

resistor. When the XSHUT pin is not controlled, the power-up sequence starts as shown in the figure below.

In this case, the device goes automatically to software standby after boot, without entering the hardware

standby mode.

Figure 16. Power up and boot sequence with a pull-up resistor

XShut

System state Power off SW standbyBoot

Power supply

Note: The AEK_SNS_VL53L1X component uses option 1. This means that when more than one sensor is

used, each sensor XSHUT pin has to be connected. Then, the host turns the sensor on by using the

AEK_TOF_CONFIG procedure.

UM3006

VL53L1X

UM3006 - Rev 1 page 10/38

Inhaltsverzeichnis

Andere ST Hauptplatine Handbücher

ST SPC584B-DISP Bedienungsanleitung

ST STM320518-EVAL Bedienungsanleitung

ST STEVAL-AKI001V1 Bedienungsanleitung

ST STM32H7 Nucleo-144 Bedienungsanleitung

ST UM2711 Bedienungsanleitung

ST EVALSP320SCPU Bedienungsanleitung

ST STM32H757I-EVAL Bedienungsanleitung

ST STEVAL-ILH007V1 Bedienungsanleitung

ST STEVAL-IPC002V1 Bedienungsanleitung

ST SPC58XXADPT144S REV.B Bedienungsanleitung

ST STEVAL-MKI019V1 Bedienungsanleitung

ST STEVAL-PCC008V1 Bedienungsanleitung

ST X-NUCLEO-IDW01M1 Bedienungsanleitung

ST eMotion STEVAL-MKI109V1 Bedienungsanleitung

ST EVALSP820-XS Bedienungsanleitung

ST STM32L476ZG Bedienungsanleitung

ST ST25RU3993-EVAL Bedienungsanleitung

ST NUCLEO-H745ZI-Q Bedienungsanleitung

ST STEVAL-ISW001V1 Bedienungsanleitung

ST STM32CubeH7 Bedienungsanleitung

ST AEKD-USBTYPEC1 Bedienungsanleitung

ST EVALKITSTKNX Bedienungsanleitung

ST STM32G081B-EVAL Bedienungsanleitung

ST STM8T141-EVAL Bedienungsanleitung

Beliebte Hauptplatine Handbücher anderer Marken

DFI

DFI SD170 Bedienungsanleitung

ASROCK

ASROCK ROMED8-2T Bedienungsanleitung

Asus

Asus P2L97A Bedienungsanleitung

Winmate

Winmate IC70 Bedienungsanleitung

Asus

Asus MES-B Bedienungsanleitung

Grantech

Grantech SYS8F377VGGA-3OMN Bedienungsanleitung

Telit Wireless Solutions

Telit Wireless Solutions SL869-3DR Bedienungsanleitung

Texas Instruments

Texas Instruments ADS8372EVM Bedienungsanleitung

Commell

Commell MS-C73 Bedienungsanleitung

Gigabyte

Gigabyte GA-9IVDT Bedienungsanleitung

IBT Technologies

IBT Technologies MB860 Bedienungsanleitung

Nvidia

Nvidia TEGRA DG-04927-001_V01 Bedienungsanleitung

Intel

Intel D33217CK Bedienungsanleitung

Asus

Asus F1A55-M LX PLUS R2.0 Bedienungsanleitung

EPC

EPC EPC9147C Bedienungsanleitung

Asus

Asus EX-B760M-V5 D4 Bedienungsanleitung

EPOX

EPOX MU-8KHA0010 Bedienungsanleitung

Ski-Doo

Ski-Doo Bombardier MPEM 219 700 090 Bedienungsanleitung