{"id":2800,"date":"2020-07-04T00:35:00","date_gmt":"2020-07-04T00:35:00","guid":{"rendered":"https:\/\/volksswitch.org\/?page_id=2800"},"modified":"2020-07-06T20:03:36","modified_gmt":"2020-07-06T20:03:36","slug":"rfid-switch-initial-hardware-test-results","status":"publish","type":"page","link":"https:\/\/volksswitch.org\/index.php\/volks-devices\/the-volksswitch\/an-rfid-based-at-switch\/rfid-switch-initial-hardware-test-results\/","title":{"rendered":"RFID Switch – Initial Hardware Test Results"},"content":{"rendered":"\n

I initially purchased an Impinj RS-1000 development kit<\/a> and, later, a ThingMagic RAIN Starter Kit<\/a>.\u00a0 Shortly after my purchase of the Impinj kit, Impinj announce the end-of-life for the product so I moved to the ThingMagic starter kit.\u00a0 At $150 the\u00a0 ThingMagic kit was very attractive but it only supports an on-board antenna which has a sub-24 inch read range, so that reader was abandoned as well. The SparkFun Simultaneous RFID Reader \u2013 M6E Nano<\/a> has been on backorder for most of the year and so, wasn’t included in the initial testing.\u00a0 It appears to be available as of this date.<\/p>\n

After some further research, I purchased a ThingMagic USB Pro RFID Reader Development Kit<\/a>.\u00a0 It has a steep price at $787 but included sample tags and a linear polarized antenna and cable.\u00a0 The reader, sans sample tags and antenna, can be had for $525 which is still relatively expensive but saves $242 over the cost of the kit.<\/p>\n

I learned several things by using the USB Pro reader and antenna.\u00a0 The first thing I learned is that the size of the tag (basically the size of the tag’s antenna) is directly proportional to the tag’s read distance.\u00a0 Second I learned that a square (two-dimensionally symmetric) tag can be read more reliably in different orientations than a rectangular (one-dimensionally symmetric) tag:<\/p>\n\n\n\n\n\n\n
Example Square Tag<\/strong><\/td>\nExample Rectangular Tag<\/strong><\/td>\n<\/tr>\n
\"\"<\/a><\/td>\n\"\"<\/a><\/td>\n<\/tr>\n
SMARTRAC Frog 3D RFID Wet Inlay 53mm (Monza 4QT)<\/a><\/td>\nSMARTRAC R6-P DogBone RFID Wet Inlay (Monza R6-P)<\/a><\/td>\n<\/tr>\n
Cost per tag: $1.50<\/td>\nCost per tag: $0.65<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Finally, I learned that the antenna that comes with the kit is linearly polarized.\u00a0 This means that the antenna can read over a long distance but can entirely miss a tag that isn’t oriented in a specific way or located in a specific place.\u00a0 As a result, I’ve invested instead in a circularly polarized antenna<\/a>.<\/p>\n

The following video illustrates the difference between the two antenna polarizations.<\/p>\n