<html xmlns="http://www.w3.org/1999/xhtml" xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office"><head><!--[if gte mso 9]><xml><o:OfficeDocumentSettings><o:AllowPNG/><o:PixelsPerInch>96</o:PixelsPerInch></o:OfficeDocumentSettings></xml><![endif]--></head><body><div style="color:#000; background-color:#fff; font-family:Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div id="yui_3_16_0_ym19_1_1493005766610_2835"> I like the idea of color indicating absorbent, </div><div id="yui_3_16_0_ym19_1_1493005766610_2834" dir="ltr">only problem is my scrubber will be positioned where I can't see it.</div><div id="yui_3_16_0_ym19_1_1493005766610_2891" dir="ltr">I just did a quick Google & came up with this color sensor.</div><div id="yui_3_16_0_ym19_1_1493005766610_2849" dir="ltr"><a class="enhancr2_79511402-752b-2c79-17fc-c344ff594f87" id="yui_3_16_0_ym19_1_1493005766610_2859" href="https://www.adafruit.com/product/1334">RGB Color Sensor with IR filter and White LED - TCS34725</a></div><div id="yui_3_16_0_ym19_1_1493005766610_3073"><br></div><div class="yahoo-link-enhancr-card yahoo-link-enhancr-not-allow-cover ymail-preserve-class ymail-preserve-style" id="enhancr2_79511402-752b-2c79-17fc-c344ff594f87" style='font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; max-width: 400px;' dir="ltr" contenteditable="false" data-size="medium" data-type="yenhancr" data-category="article" data-embed-url="" data-url="https://www.adafruit.com/product/1334"> <a class="yahoo-enhancr-cardlink" id="yui_3_16_0_ym19_1_1493005766610_2890" style="color: rgb(0, 0, 0) !important; text-decoration: none !important;" href="https://www.adafruit.com/product/1334" target="_blank" rel="noreferrer"> <table class="card-wrapper" id="yui_3_16_0_ym19_1_1493005766610_2889" style="max-width: 400px;" border="0" cellspacing="0" cellpadding="0"> <tbody id="yui_3_16_0_ym19_1_1493005766610_2888"><tr id="yui_3_16_0_ym19_1_1493005766610_2887"> <td width="400" id="yui_3_16_0_ym19_1_1493005766610_2886"> <table width="100%" class="card-info" id="yui_3_16_0_ym19_1_1493005766610_2885" style="background: rgb(255, 255, 255); border-width: 1px 1px 3px; border-style: solid; border-color: rgb(224, 228, 233) rgb(224, 228, 233) rgb(0, 0, 0); border-image: none; max-width: 400px;" border="0" cellspacing="0" cellpadding="0"> <tbody id="yui_3_16_0_ym19_1_1493005766610_2884"><tr id="yui_3_16_0_ym19_1_1493005766610_2883"> <td style="padding: 16px 0px 16px 12px; vertical-align: top;"> </td> <td id="yui_3_16_0_ym19_1_1493005766610_2882" style="padding: 16px 12px; width: 99%; vertical-align: middle;"> <h2 class="card-title" style='margin: 0px 0px 4px; font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 16px;'>RGB Color Sensor with IR filter and White LED - TCS34725</h2> <div class="card-richinfo-primary" style="color: rgb(153, 153, 153); line-height: 15px; font-size: 11px;">By Adafruit Industries</div> <div class="card-description" style="color: rgb(153, 153, 153); line-height: 15px; font-size: 11px;">Your electronics can now see in dazzling color with this lovely color light sensor. We found the best color sens...</div> </td> <td class="card-share-container"></td> </tr> </tbody></table> </td> </tr> </tbody></table> </a></div><div id="yui_3_16_0_ym19_1_1493005766610_2892"><br></div><div id="yui_3_16_0_ym19_1_1493005766610_2893" dir="ltr">If you put multiple sensors down the outside of an acrylic scrubber canister you could</div><div id="yui_3_16_0_ym19_1_1493005766610_3008" dir="ltr">read the color change in the absorbent & have it displayed elsewhere. </div><div id="yui_3_16_0_ym19_1_1493005766610_3007" dir="ltr">You could perhaps use the one sensor board with multiple sensors. Another variation is</div><div id="yui_3_16_0_ym19_1_1493005766610_2963" dir="ltr">that you may be able to pick up the heat from the chemical reaction with the infrared</div><div id="yui_3_16_0_ym19_1_1493005766610_3030" dir="ltr">sensor & monitor levels that way.</div><div id="yui_3_16_0_ym19_1_1493005766610_3029" dir="ltr"> An additional thought on this subject is to put a second CO2 sensor at the outlet of the </div><div id="yui_3_16_0_ym19_1_1493005766610_3053" dir="ltr">scrubber to pick up early when there were higher concentrations of CO2 coming out.</div><div id="yui_3_16_0_ym19_1_1493005766610_3074" dir="ltr">So sensor 1 is the ambient atmosphere concentration & sensor 2 is showing what</div><div id="yui_3_16_0_ym19_1_1493005766610_3104" dir="ltr">level of CO2 there is from the scrubber that will be mixing with the atmosphere.</div><div id="yui_3_16_0_ym19_1_1493005766610_3128" dir="ltr">Alan</div><div id="yui_3_16_0_ym19_1_1493005766610_3103" dir="ltr"><br></div><div id="yui_3_16_0_ym19_1_1493005766610_3054" dir="ltr"><br></div></div></body></html>