databot™ Basic Training

Sensor Starters: Ambient Light!

databot™ has an ambient light sensor on board that can be used in all kinds of fun ways.  Let’s check it out!

Sensor Starters - Meet the Lux Sensor!

The light sensor on board databot™ is the APDS-9301 miniature ambient light photo sensor manufactured by Avago.  This awesome little package was built to respond in a fashion similar to the human eye – so it’s essentially seeing the same light levels you do. 

This  sensor is used in a variety of devices to control display backlighting such as cell phones, notebooks, tablets, flat panel TVs, etc.  It’s also used for automated light management, electronic signs and signal, dashboard light controls and other devices that react to light levels.  When you see a street light turn on, or your phone screen automatically dim based on the lights going down, it’s because of a sensor just like this one. 

Look on the main sensor board and look for the sensor – it will be labeled “Lux.”  

How does it Work?

This sensor uses photodiodes to convert light into electrical current.  Photons strike the photodiodes and generate current that is then measured and converted to output units such as Lux.

What are the Units?

 

 

The lux (symbol: lx) is the International System of Units (SI) unit of measurement equal to one lumen per square meter. For the purposes of beginning experimentation lux  is a standardized unit of measurement of light.  Students can take comparative readings throughout a classroom, for example, to begin to grasp the correlation between units of lux and brightness.  To dive into it deeper, do some research on lux and lumens.  Look for links and resources at the end of this document.

Examples of Light Levels in Lux

Light Condition Lux Level
Sunlight
107,527
Full Daylight
10,752
Overcast Day
1075
Very Dark Day
107
Classroom or Office
300-500
Warehouse
150-250
Supermarket
750

Science Journal Setup

If you haven’t setup your Science Journal app yet do that now and come back to these Sensor Starter activities.

Begin your Lux explorations by creating a new experiment in your Journal as follows:

  1. Open Science Journal.
  2. Select the plus sign.  
  3. Select the pencil icon in the header bar to edit your title and journal display image.  
  4. Edit the title – give your new experiment entry an interesting and descriptive name.
  5. Add an image to the experiment so your portfolio is colorful  to look at.  You can take a picture or upload an image you like.
  6. Save this information by clicking on the check mark.

Congrats!  Use the back arrow to exit your experiment and admire your work. Check out your newly titled and imaged experiment!

Science Journal Data Test

Return to your experiment and open the sensor display area by clicking on the data icon in the observations section.  It looks like a circle with a wavy line through it. 

Depending on your device, a sensor display “card” will appear – perhaps the internal microphone or ambient light on the device or Chromebook you are using.

Time to get the Lux sensor loaded! 

  1. Enter the Sensor Settings menu by selecting the “gear wheel” on the open sensor card.
  2. De-select all sensors except the databot Ambient Light sensor.
  3. Exit the sensor settings menu using the back arrow.
  4. Select the Plus sign beneath the default sensor card and your databot™ ambient light sensor data should appear!  

Test it by watching the data display and covering and uncovering databot.  You should see the data  display change with the light intensity.

Welcome to the Data Game - Lux!

The Data Game is a quick and fun introduction to databot sensors that includes each sensor’s location on the ‘bot,  what it measures, and its units.  Use these Data Game Challenges to quickly engage students and convey some important core science concepts

Familiarize yourself with light levels by experimenting with the databot in different environments. Use the table provided to gain a general understanding of the lux range of lighting under different circumstances

 Prepare to give your students some fun challenges!

The Data Game - What's a Lux?

Introduce students to the term “lux” and explain how it is a measurement of  an amount of light over a specific area – 1 lumen over 1 square meter.

Use the lux environment table  to provide some context for levels of brightness described in lux.  

Prepare the students for some challenges now with Lux using databot!

Challenge 1 - Find the Sensor!

Lux Sensor Location

 

One of the objectives of the data game is to familiarize yourself and students with the construction of databot and where sensors and other components are located. Take a look at the main sensor board on the front of databot™ and look for the lux label.   The sensor should look similar to the image at the beginning of this activity.

Depending on how many databot™s you have, pass one around the room and have students find it or put them into groups and challenge them to find it as a group.  Tell them to look for the term “lux” and raise their hand when they find it. 

Challenge 2 - Bright, Dim, & Precision!

Time to go on an illumination safari.  In groups or individually, students need to create an experiment in Google Science Journal and prepare to record data and make notes on the following challenges.

 

  1. Find the brightest spot in the classroom. Add notes or  pictures to capture the location of your bright spot and your observations about it.
  2. Find the dimmest spot in the classroom. Record the data to capture your low reading. Add notes or  pictures to capture the location of your dim spot and your observations about it.
  3. Find a spot in the classroom with exactly 350 Lux! Add notes or  pictures to capture the location of your precision spot and your observations about it.  Describe what you had to do to get an exact reading of 350 lux.

Challenge 3 - Pass the Light Please!

Light travels in waves, and depending on the medium it is passing through certain wavelengths may pass through unhindered and some may be blocked.  Try placing different materials such as different colored papers or fabrics in front of the databot lux sensor to accomplish the following:

  1. Find a material that does not affect the lux level at all.
  2. Identify a material that will cut the lux level in half when placed in front of the sensor .  This is a tough one to get exact.  Experiment not just with the material but also the distance from the sensor and different light sources to see if you can accomplish it. 
  3. Identify a material that blocks the transmission of light entirely.

Attribution & Resources

  1. The National Optical Astronomy Observatory at Kitt Peak in California has produced some wonderful educational resources on the topic of light.  Check the references below to check out their educational resources on this topic.  
  2. National Optical Astronomy Observatory Educational Resources
  3. Teacher Reference – National Optical Astronomy Observatory Recommended Light Levels
  4. Slideshare presentation on the characteristics of light.
  5. Wikipedia Entry – Lux 
  6. Photodiode Symbol, Creative Commons 3.0
  7. The “Data Game” idea provided by Jeremy Mallet, St. Basin Catholic School; databot™ Giveaway 2019.”

Wrap Up!

This concludes your introduction to the ambient light sensor!  Challenge your students to come up with their own experiments to go deeper, and explore the growing body of activities using all the databot sensors in the lessons and activities area.

Ready to Move On?

If you’re doing the Sensor Starters in order, your next stop is the UV sensor!  Good luck and have fun!

Explore Ultraviolet Light