feat: implementation of the veml7700 driver

.github/labeler.yml

@@ -664,3 +664,11 @@ labels:
           - "components/ads130e08/**"
           - "components/ads130e08/.eil.yml"
           - "examples/ads130e08/**"
+  - label: "area:components:veml7700"
+    sync: true
+    matcher:
+      files:
+        any:
+          - "components/veml7700/**"
+          - "components/veml7700/.eil.yml"
+          - "examples/veml7700/**"

README.md

@@ -202,6 +202,7 @@ or [GitLab examples](https://gitlab.com/UncleRus/esp-idf-lib/tree/master/example
 | **tsl2561**              | Driver for light-to-digital converter TSL2561                                    | BSD-3   | `esp32`, `esp8266`, `esp32s2`, `esp32c3` | Yes
 | **tsl2591**              | Driver for light-to-digital converter TSL2591                                    | MIT     | `esp32`, `esp8266`, `esp32s2`, `esp32c3` | Yes
 | **tsl4531**              | Driver for digital ambient light sensor TSL4531                                  | BSD-3   | `esp32`, `esp8266`, `esp32s2`, `esp32c3` | Yes
+| **veml7700**             | Driver for VEML7700 ambient light sensor                                         | ISC     | `esp32`, `esp8266`, `esp32s2`, `esp32c3` | Yes
 
 ### Magnetic sensors
 
@@ -308,3 +309,4 @@ or [GitLab examples](https://gitlab.com/UncleRus/esp-idf-lib/tree/master/example
 - [Jose Manuel Perez](https://github.com/jmpmscorp), developer of LC709203F driver
 - [Weslley Duarte](https://github.com/weslleymfd), developer of ADS130E08 driver
 - [Jan Veeh](https://github.com/janveeh), developer of ICM42670 driver
+- [Marc Luehr](https://github.com/Th3Link), developer of VEML7700 driver

components/veml7700/.eil.yml

@@ -0,0 +1,23 @@
+---
+components:
+  - name: veml7700
+    description: Driver for VEML7700 ambient light sensor
+    group: light
+    groups: []
+    code_owners: Th3Link
+    depends:
+      - i2cdev
+      - log
+      - esp_idf_lib_helpers
+    thread_safe: yes
+    targets:
+      - name: esp32
+      - name: esp8266
+      - name: esp32s2
+      - name: esp32c3
+    licenses:
+      - name: ISC
+    copyrights:
+      - author:
+          name: Th3Link
+        year: 2019

components/veml7700/CMakeLists.txt

@@ -0,0 +1,5 @@
+idf_component_register(
+    SRCS veml7700.c
+    INCLUDE_DIRS .
+    REQUIRES i2cdev log esp_idf_lib_helpers
+)

components/veml7700/LICENSE

@@ -0,0 +1,17 @@
+ISC License
+
+SPDX-License-Identifier: ISC
+
+Copyright (c) 2022 Marc Luehr <marcluehr@gmail.com>
+
+Permission to use, copy, modify, and distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

components/veml7700/README.md

@@ -0,0 +1,104 @@
+# Driver for the VEML7700 ambient light sensor
+
+This is the driver for the VEML7700 ambiernt light sensor from Vishay. It is not the
+cheapest solution but very easy to integrate, with a minimum of further components.
+The sensor can be SMD soldered by hand on a custom PCB, but also several breakout boards 
+are available.
+
+## About the sensor
+
+The VEML7700 is a high-accuracy ambient light sensor. All measurements and filtering
+is done on the chip which makes it easy to integrate. The sensitivity can be adjusted
+by a gain setting and by changing the integration time. The output of the sensor is a
+count value which must be converted using the resolution value in the driver. 
+
+The sensor has power saving features which reduces the repetition of measurements.
+It has also a power off feature to save even more power.
+
+The ambient light sensor value is filterd very clone to the caracteristic of the
+human eye. Besides, als the white channel with a wider wavelength spectrum. In most
+applications, the ambient light value will do just fine.
+
+## Power consumption
+
+- 0.5 μA in shut-down mode (@3.3V)
+- down to 2 μA in power save mode 4 (@3.3V)
+- 45 μA on 100ms integration time (@3.3V)
+
+## Communication interface
+
+I2C is used as communication interface without any further interrupt pins. It has six
+command codes for the settings and the output values. Read the datasheet or application
+note for further information.
+
+To reduce interactions with the integrated microcontroller, the interrupt feature can
+be used. Therefore, one must configure the low and high threshold and enable the interrupt.
+
+## Interrupt application examples
+
+If values below a certain threshold is of interest, i.e. to activate lights when its 
+getting dark outside, the low threshold should be adjusted and setting the high threshold
+to maximum (65535). 
+
+Another application could be an automated rollershutter, then both thresholds sould be
+set to trigger the up and down movement of rollershutters.
+
+## Measurement process
+
+The measurement takes time and the sensor should not be read out faster than the
+measurement time. Therefore the application should be adjusted to the sensor configuration
+regarting integration time and power save modes. Alternatively, the interrupt feature
+can be used by repeatetive reading of the interrupt status.
+
+## Usage
+
+This driver uses i2cdev which must be initialized first. Then initialize the device
+decriptor, one discriptor per device. The sensor can be used without configuration,
+but has a high chance of over-saturation on sunlight. Therefore, change gain and
+integration time to your needs and configure the device.
+
+Then, the veml7700_ambient_light and veml7700_white_channel functions can be used
+to read out the brightness. The driver converts the counts from the device to lx using
+the configuration.
+
+### Hardware configurations
+
+The driver supports multiple VEML7700 sensors at the same time that are
+connected to I2C. Following figure show some possible hardware
+configurations.
+
+First figure shows the configuration with one sensor at I2C bus 0.
+
+```text
+ +------------------+   +----------+
+ | ESP8266 / ESP32  |   | VEML7700 |
+ |                  |   |          |
+ |   GPIO 14 (SCL)  ----> SCL      |
+ |   GPIO 13 (SDA)  <---> SDA      |
+ +------------------+   +----------+
+```
+
+Next figure shows a possible configuration with two I2C buses.
+
+```text
+ +------------------+   +----------+
+ | ESP8266 / ESP32  |   | VEML7700 |
+ |                  |   |          |
+ |   GPIO 14 (SCL)  ----> SCL      |
+ |   GPIO 13 (SDA)  <---> SDA      |
+ |                  |   +----------+
+ |                  |   | VEML7700 |
+ |                  |   |          |
+ |   GPIO 5  (SCL)  ----> SCL      |
+ |   GPIO 4  (SDA)  <---> SDA      |
+ +------------------+   +----------+
+```
+
+Only one sensor per I2C bus is possible, since it uses a unconfigurable I2C slave address. 
+However, one could also use GPIO controller bus buffer to connect the bus to different 
+devices.
+
+## References
+[Datasheet](https://www.vishay.com/docs/84286/veml7700.pdf)
+
+[Application Note](https://www.vishay.com/docs/84323/designingveml7700.pdf)

components/veml7700/component.mk

@@ -0,0 +1,2 @@
+COMPONENT_ADD_INCLUDEDIRS = .
+COMPONENT_DEPENDS = i2cdev log esp_idf_lib_helpers