11 Replies Latest reply on Sep 23, 2018 9:22 PM by littleben1

    Sensing Skin is present

    hasher

      Hi guys

       

      I am working on a project that  involves detection of skin (and hair). The sensor should be in such a way that it should differentiate human skin from other objects like wood,dirt . Is there a commercial sensor on the market that does this ?

       

       

      Thanks Paul

        • Re: Sensing Skin is present
          Fred27

          The standard way of detecting touch as capacitive sensing. This doesn't specifically discriminate between skin and other objects, but there are ways to ignore non-specific contact - e.g. a whole hand or water/dirt over a panel of buttons. Does this meet your needs? You may need to be a bit more specific about what you're trying to achieve.

          5 of 5 people found this helpful
            • Re: Sensing Skin is present
              hasher

              Well  I want to know when two animals push against each other to trigger a data point. So the sensor is mounted on the animals chest and I want to know when they mate. Obviously there is a lot hair in the way. Think of a cow or a horse. If it was a pressure sensor it might trigger whilst laying on the ground or rubbing against something.

               

              I can only mount my sensor on the male . Not both animals

               

              Even a combination of pressure and skin detection might reduce error. Plus I don't know if skin detection will work with so much hair.

               

              I know this is quirky but has application in farming

              4 of 4 people found this helpful
                • Re: Sensing Skin is present
                  Fred27

                  I think that would work, although there is still the chance of false positives. There are plenty of microcontrollers that do capacitive sensing - you won't even need something as powerful as a SBC. I'm familiar with TI's MSP430 range and there was even a project14 episode on using a MSP430FR2633 dev board as a proximity sensor.

                   

                  Episode 356: Bank to the Future with Arduino & TI

                  hasher  wrote:

                  I know this is quirky but has application in farming

                  I'm glad you cleared that up! Otherwise it would have just been weird.

                  4 of 4 people found this helpful
                  • Re: Sensing Skin is present
                    mcb1

                    You should be able to combine with detecting a change in the relative chest position.

                    Either tilt switch or accelerometer to detect both the accelration vertically and then the change in it's position for a period of time.

                     

                    Here they simply use different coloured marker bags ...

                     

                    Mark

                    4 of 4 people found this helpful
                    • Re: Sensing Skin is present
                      the48sicks

                      Oh I love this!

                       

                      Back many moons ago when we did this on the farm the old-fashioned way. We used to paint “his” chest with a bright color water-based solution and then send him out into the paddock

                       

                      Any ladies that received any of his attention would have a marking on her back!

                       

                      Taking this in another direction you could use something like the Adafruit pixy 2 (https://www.adafruit.com/product/1906) to identify any animals that want back out through the gate with a color painted in it, even pair it with a thermal camera to get a head count of warm things running past.

                       

                      Would also save having to hot glue a nano & lipo battery to the buck (just kidding!)

                       

                       

                      Matt

                  • Re: Sensing Skin is present
                    genebren

                    Capacitive sensing is a good way to go.  I have used multiple capactive sensors in an array to detect proper (full) contact with skin in a medical product.  The idea was to require multiple contact points to verify a verified contact.  If the fur does get in the way (which should not be too much of a problem), you could augment the detection with an I/R sensor to provide an added component of heat to the equation to assist in eliminating false/casual contact.

                     

                    Gene

                    2 of 2 people found this helpful
                    • Re: Sensing Skin is present
                      littleben1

                      Maybe there would be a way to have the males positively charged and the females negatively charged or grounded (very very small amounts of charge) so that there would be a drop in charge on the male when it comes in contact with a female, still would be a type of capacitive sensing but might be what you would be looking for. the biggest problem with all of this is any time that the animals are standing in mud that is deep enough to ground there is going to be false positives. other than that maybe some sort of individual gps tags that would show when two of the animals were within close contact of each other, in that case you could have individual identifiers for each tag so you would know the males and the females and then only have it activate to give a reading when the two had been together for more than just a split second to help weed out false positives. or find some way to run small magnets and hall effect sensors to an area on each animal that would be close together while the mating was in progress. just some ideas but I hope they help, I also come from a farming area (my father has a couple of farms) so I completely understood what you were getting after. anyways hope it helps

                      1 of 1 people found this helpful
                      • Re: Sensing Skin is present
                        dougw

                        I don't know how you would physically attach this to an animal, but as mentioned by genebren above, you cold use capacitance sensing. If 2 plates of a capacitor are separated by a few inches and another animal comes in fairly close contact with both you can easily detect a difference in capacitance between the plates. The plates could simply be insulated wires. There would be a maximum capacitance range due to the animal wearing the circuit and a close encounter would increase it. I could also imaging some small circuit module the size of a match book hanging off an animal that included the counting circuit as well as the sensor and battery. When it gets "sandwiched" it would know it. Check this road test to get an idea of sensitivity.

                        1 of 1 people found this helpful