Hi!
I have an idea to build a watermelon sweetness detector. It should work without damaging the berry. I was thinking about an ultrasonic sensor to detect the density or about a mic with some knocking mechanism. Any ideas?
You need to determine how this is measured by industry or is this idea totally new ? I doubt you’ll find and fruit specialists here ( fruit cakes - yes)
I expect like a lot of fruit , it’s done by destructive testing of samples.
Could be anything? Colour, density, elastisity, smell .. or a combination...
If it’s a new idea you need to measure a pile of parameters, then taste the fruit and look for correlation. Patent it, sit make and make a fortune .
Or google it ...
Tofer:
Hi!I have an idea to build a watermelon sweetness detector. It should work without damaging the berry. I was thinking about an ultrasonic sensor to detect the density or about a mic with some knocking mechanism. Any ideas?
The melons grown 50-75 years ago developed a void when the seed matrix disintegrated when ripe and let the heart drop down. You could hear the echo when you thumped them.
Today's melons, that does not happen because they are all designed for shipment to market.
My wife learned to look for the drying up of stem tendrils near the melon. We have proven this year that that test does work and the melons are wonderful?
I don't see anyway for that test to be automated.
Paul
I stand corrected on the fruit expert bit !! Lol
Not a fruit expert... but I do routinely see people knock water melons nowadays as way of checking the quality before buying one (at least I suppose that's what they're trying to do) and I'm also used to see large cracks (and voids) inside the ripe melons when they're cut open. It must be possible to automate this: something that gently knocks the fruit, a microphone that listens to the sound, and some sound analyses. Would need a bit more powerful hardware than a basic Arduino, of course.
Nonetheless that'd be a ripeness detector (ripe or not), rather than a sweetness detector. Now I don't even know how to measure or define "sweetness" - I guess it'd have to be a measurement of how much of certain chemicals are present, such as fructose or other sugars. In turn no idea how one could do that non-destructively (where that's a bit of a big word here - without taking a physical sample would be a better description).
wvmarle:
Not a fruit expert... but I do routinely see people knock water melons nowadays as way of checking the quality before buying one (at least I suppose that's what they're trying to do) and I'm also used to see large cracks (and voids) inside the ripe melons when they're cut open. It must be possible to automate this: something that gently knocks the fruit, a microphone that listens to the sound, and some sound analyses. Would need a bit more powerful hardware than a basic Arduino, of course.Nonetheless that'd be a ripeness detector (ripe or not), rather than a sweetness detector. Now I don't even know how to measure or define "sweetness" - I guess it'd have to be a measurement of how much of certain chemicals are present, such as fructose or other sugars. In turn no idea how one could do that non-destructively (where that's a bit of a big word here - without taking a physical sample would be a better description).
Fire up the MRI and take a scan...
Sweetness detector, use a syringe and suck some goodness out of it and analyse the sample.
Tom..... 
TomGeorge:
Sweetness detector, use a syringe and suck some goodness out of it and analyse the sample.
Now the trick is to take a representative sample, as the middle of the fruit tends to be much sweeter than the part near the skin.
wvmarle:
Now the trick is to take a representative sample, as the middle of the fruit tends to be much sweeter than the part near the skin.
Use a heart needle.
Birds seem to find the sweetest ones in my garden. Not sure PETA would appreciate us making a circuit that used a birds head, but as long as they don’t care please feel free to test on the ones in my yard..
That's probably based on smell.
Slumpert:
Birds seem to find the sweetest ones in my garden.
What bird is it that eats whole watermelons?
Paul__B:
What bird is it that eats whole watermelons?
This one?
