Adafruit VEML7700 User Guide

Adafruit VEML7700 Ambient Light Sensor

Created by Kattni Rembor

https://learn.adafruit.com/adafruit-veml7700

Last updated on 2022-02-16 03:54:54 PM EST

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Table of Contents

Overview

Pinouts

• Power Pins

• I2C Logic Pins

Assembly

• Prepare the header strip:

• Add the breakout board:

• And Solder!

Arduino

• Wiring

• Installation

• Load Example

• Example Code

Arduino Docs

Python & CircuitPython

• CircuitPython Microcontroller Wiring

• Python Computer Wiring

• CircuitPython Installation of VEML7700 Library

• Python Installation of VEML7700 Library

• CircuitPython & Python Usage

• Full Example Code

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Python Docs

Downloads

• Files

• Schematic and Fab Print for STEMMA QT Version

• Schematic and Fab Print for Original Version

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Overview

Vishay has a lot of light sensors out there, and this is a nice simple lux sensor that's

easy to add to any microcontroller. Most light sensors just give you a number for

brighter/darker ambient lighting. The VEML7700 makes your life easier by calculating

the lux, which is an SI unit for light. You'll get more consistent readings between

multiple sensors because you aren't dealing with some unitless values.

The sensor has 16-bit dynamic range for ambient light detection from 0 lux to about

120k lux with resolution down to 0.0036 lx/ct, with software-adjustable gain and

integration times.

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Interfacing is easy - this sensor uses plain, universal I2C. We put this sensor on a

breakout board with a 3.3V regulator and logic level shifter so you can use it with

3.3V or 5V power/logic microcontrollers. We have written libraries for Arduino(https:/

/adafru.it/EoE) (C/C++) as well as CircuitPython (Python 3)(https://adafru.it/EoF) so you

can use this sensor with just about any kind of device, even a Raspberry Pi!

This is Kattni's first PCB design for Adafruit, it's even signed on the back!

As with all Adafruit breakouts, we've done the work to make this handy light sensor

super easy to use. We've put it on a breakout board with the required support

circuitry and connectors to make it easy to work with. Since I2C is supported, we've

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addedSparkFun Qwiic(https://adafru.it/Fpw)compatibleSTEMMA QT(https://

adafru.it/Ft4)JST SH connectors that allow you to get goingwithout needing to

solder.Just use aSTEMMA QT adapter cable(https://adafru.it/FA-), plug it into your

favorite microcontroller or Blinka supported SBC and you're ready to rock!QT Cable

is not included, but we have a variety in the shop(https://adafru.it/JnB).

There are two versions of this board - the STEMMA QT version shown above, and

the original header-only version shown below. Code works the same on both!

Pinouts

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Power Pins

Vin - this is the power pin. Since the sensor chip uses 3 VDC, we have included

•

a voltage regulator on board that will take 3-5VDC and safely convert it down.

To power the board, give it the same power as the logic level of your

microcontroller - e.g. for a 5V micro like Arduino, use 5V

3Vo - this is the 3.3V output from the voltage regulator, you can grab up to

•

100mA from this if you like

GND - common ground for power and logic

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I2C Logic Pins

SCL - this is the I2C clock pin, connect to your microcontroller's I2C clock line.

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SDA - this is the I2C data pin, connect to your microcontroller's I2C data line.

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STEMMA QT(https://adafru.it/Ft4) - These connectors allow you to connect to

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development boards with STEMMA QT connectors, or to other things, with vario

us associated accessories(https://adafru.it/Ft6).

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Assembly

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Prepare the header strip:

Cut the strip to length if necessary. It will

be easier to solder if you insert it into a

breadboard -long pins down

Add the breakout board:

Place the breakout board over the pins

so that the short pins poke through the

breakout pads

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And Solder!

Be sure to solder all 5 pins for reliable

electrical contact.

(For tips on soldering, be sure to check

out ourGuide to Excellent

Soldering(https://adafru.it/aTk)).

You're done! Check your solder joints

visually and continue onto the next steps

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Arduino

Wiring

Connecting the VEML7700 to your Feather or Arduino is easy:

If you are running a Feather (3.3V),

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connectFeather 3V to board VIN

(red wire on STEMMA QT version)

If you are running a 5V Arduino

•

(Uno, etc.), connect Arduino 5V

toboard VIN (red wire on STEMMA

QT version)

Connect Feather or Arduino GND to

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board GND (black wire on STEMMA

QT version)

Connect Feather or Arduino SCL to

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board SCL (yellow wire on STEMMA

QT version)

Connect Feather or Arduino SDA to

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board SDA (blue wire on STEMMA

QT version)

The final results should resemble the illustration above, showing an Adafruit Metro

development board.

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Installation

You can install the Adafruit VEML7700 Library for Arduino using the Library Manager

in the Arduino IDE:

Click theManage Libraries ... menu item, search for Adafruit VEML7700,and select

theAdafruit VEML7700 library:

Then follow the same process for the Adafruit BusIO library.

Load Example

Open upFile -> Examples -> Adafruit VEML7700 -> veml7700_test and upload to your

Arduino wired up to the sensor.

Upload the sketch to your board and open up the Serial Monitor (Tools->Serial

Monitor). You should see the the values for Lux, white light, and raw ambient light

levels.

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Example Code

The following example code is part of the standard library, but illustrates how you can

retrieve sensor data from the VEML7700 for the Lux, white light and raw ambient light

values:

#include "Adafruit_VEML7700.h"

Adafruit_VEML7700 veml = Adafruit_VEML7700();

void setup() {

while (!Serial) { delay(10); }
Serial.begin(115200);
Serial.println("Adafruit VEML7700 Test");

if (!veml.begin()) {
Serial.println("Sensor not found");
while (1);
}
Serial.println("Sensor found");

veml.setGain(VEML7700_GAIN_1);
veml.setIntegrationTime(VEML7700_IT_800MS);

Serial.print(F("Gain: "));
switch (veml.getGain()) {
case VEML7700_GAIN_1: Serial.println("1"); break;
case VEML7700_GAIN_2: Serial.println("2"); break;
case VEML7700_GAIN_1_4: Serial.println("1/4"); break;
case VEML7700_GAIN_1_8: Serial.println("1/8"); break;
}

Serial.print(F("Integration Time (ms): "));
switch (veml.getIntegrationTime()) {
case VEML7700_IT_25MS: Serial.println("25"); break;
case VEML7700_IT_50MS: Serial.println("50"); break;
case VEML7700_IT_100MS: Serial.println("100"); break;
case VEML7700_IT_200MS: Serial.println("200"); break;
case VEML7700_IT_400MS: Serial.println("400"); break;
case VEML7700_IT_800MS: Serial.println("800"); break;
}

//veml.powerSaveEnable(true);
//veml.setPowerSaveMode(VEML7700_POWERSAVE_MODE4);

veml.setLowThreshold(10000);
veml.setHighThreshold(20000);
veml.interruptEnable(true);
}

void loop() {

Serial.print("Lux: "); Serial.println(veml.readLux());
Serial.print("White: "); Serial.println(veml.readWhite());
Serial.print("Raw ALS: "); Serial.println(veml.readALS());

uint16_t irq = veml.interruptStatus();
if (irq & VEML7700_INTERRUPT_LOW) {
Serial.println("** Low threshold");
}
if (irq & VEML7700_INTERRUPT_HIGH) {
Serial.println("** High threshold");
}

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delay(500);
}

You should get something resembling the following output when you open the Serial

Monitor at 115200 baud:

Arduino Docs

Arduino Docs(https://adafru.it/Erg)

Python & CircuitPython

It's easy to use the VEML7700 sensor with CircuitPython and theAdafruit

CircuitPython VEML7700(https://adafru.it/EoF)module. This module allows you to

easily write Python code that reads the ambient light levels, including Lux, from the

sensor.

You can use this sensor with any CircuitPython microcontroller board or with a

computer that has GPIO and Pythonthanks to Adafruit_Blinka, our CircuitPython-for-

Python compatibility library(https://adafru.it/BSN).

CircuitPython Microcontroller Wiring

First wire up a VEML7700 to your board exactly as follows. Here is an example of the

VEML7700 wired to a Feather using I2C:

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Board 3Vtosensor VIN (red wire on

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STEMMA QT version)

Board GNDtosensor GND (black

•

wire on STEMMA QT version)

Board SCLtosensor SCL (yellow

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wire on STEMMA QT version)

Board SDAtosensor SDA (blue

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wire on STEMMA QT version)

Note: This breakout includes pullup resistors on the I2C lines, no external pullups

are required.

Python Computer Wiring

Since there'sdozensof Linux computers/boards you can use we will show wiring for

Raspberry Pi. For other platforms,please visit the guide for CircuitPython on Linux to

see whether your platform is supported(https://adafru.it/BSN).

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Here's the Raspberry Pi wired with I2C:

Pi 3V3tosensor VIN (red wire on

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STEMMA QT version)

Pi GNDtosensor GND (black wire

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on STEMMA QT version)

Pi SCLtosensor SCL (yellow wire

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on STEMMA QT version)

Pi SDAtosensor SDA (blue wire on

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STEMMA QT version)

CircuitPython Installation of VEML7700 Library

You'll need to install theAdafruit CircuitPython VEML7700(https://adafru.it/EoF) library

on your CircuitPython board.

First make sure you are running thelatest version of Adafruit CircuitPython(https://

adafru.it/Amd)for your board.

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Next you'll need to install the necessary librariesto use the hardware--carefully follow

the steps to find and install these libraries fromAdafruit's CircuitPython library bundle

(https://adafru.it/uap). Our CircuitPython starter guide has a great page on how to

install the library bundle(https://adafru.it/ABU).

For non-express boards like the Trinket M0 or Gemma M0, you'll need to manually

install the necessary libraries from the bundle:

adafruit_veml7700.mpy

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adafruit_bus_device

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adafruit_register

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Before continuing make sure your board's lib folder or root filesystem has theadafrui

t_veml7700.mpy, adafruit_bus_device, andadafruit_register files and folderscopied

over.

Nextconnect to the board's serial REPL(https://adafru.it/Awz)so you are at the

CircuitPython>>>prompt.

Python Installation of VEML7700 Library

You'll need to install the Adafruit_Blinka library that provides the CircuitPython

support in Python. This may also require enabling I2C on your platform and verifying

you are running Python 3.Since each platform is a little different, and Linux changes

often, please visit the CircuitPython on Linux guide to get your computer ready(https

://adafru.it/BSN)!

Once that's done, from your command line run the following command:

sudo pip3 install adafruit-circuitpython-veml7700

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If your default Python is version 3 you may need to run 'pip' instead. Just make sure

you aren't trying to use CircuitPython on Python 2.x, it isn't supported!

CircuitPython & Python Usage

To demonstrate the usage of the sensor we'll initialize it and read the ambient light

levels from the board's Python REPL.

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Run the following code to import the necessary modules and initialize the I2C

connection with the sensor:

import time
import board
import busio
import adafruit_veml7700

i2c = busio.I2C(board.SCL, board.SDA)
veml7700 = adafruit_veml7700.VEML7700(i2c)

Now you're ready to read values from the sensor using these properties:

light - The ambient light data.

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lux - The light levels in Lux.

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For example to print ambient light levels and lux values:

print("Ambient light:", veml7700.light)
print("Lux:", veml7700.lux)

For more details, check out the library documentation(https://adafru.it/EoQ).

That's all there is to using the VEML7700 sensor with CircuitPython!

Full Example Code

# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import time
import board
import adafruit_veml7700

i2c = board.I2C() # uses board.SCL and board.SDA
veml7700 = adafruit_veml7700.VEML7700(i2c)

while True:

print("Ambient light:", veml7700.light)
time.sleep(0.1)

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Python Docs

Python Docs(https://adafru.it/EoG)

Downloads

Files

VEML7700 Datasheet(https://adafru.it/EoR)

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EagleCAD files on GitHub(https://adafru.it/EoS)

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Fritzing object for STEMMA QT version in Adafruit Fritzing Library(https://

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adafru.it/Ytb)

Fritzing object for original version from Adafruit Fritzing Library(https://adafru.it/

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EoT)

Schematic and Fab Print for STEMMA QT Version

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Schematic and Fab Print for Original Version

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