STEMMA Soil Sensor - I2C Capacitive Moisture Sensor Toxicity

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SlantPlat
 
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STEMMA Soil Sensor - I2C Capacitive Moisture Sensor Toxicity

Post by SlantPlat »

Hello,

And thank you for any help you can provide.

I am an inventor and I have created a rugged, inexpensive vertical growing system that is nearly plant agnostic- it grows almost anything. I have extensively tested the system outside and it really is amazing.

But now I am growing inside and what with recent events, the need for this product to work indoors and out has struck me most BANNED.

My hope has always been to find a way to fund giving these to people living in refuge camps. They have nothing and no economy. But the beginning of any economy is food. My hope is to use the indoor market to fund charitable donations and shipping to people in need all over the world.

Do you have any information that may help me quantify the toxicity of these devices, if any? Obviously, the areas at the top containing connectors and circuitry would need to be protected anyway and I am sure I can do that. But are there any metals or toxic materials to worry about in the bottom portion?

I have attached a photo of one of my test gardens to help you understand how the design will use this sensor. I hope that is allowed?

The pic called TestGarden shows an outside garden at maturity. There are over 100 plants in there. GrowBays shows a close up of the bays where plants grow. (Yes, those are soda and water bottles- something we have plenty of!) I need just one moisture sensor in one bay as the system is all interconnected. This will then output to an Arduino and turn on a pump once moisture is needed. (Water recirculates with the indoor model.) The sensor is placed down along the side of the soda bottle, "grow bay" and the wires head back from there.

The problem is that I have used what I should have known would not work, that being the exposed copper version of "moisture sensors." They corrode in no time and leave metals in the soil- not good if you plan to eat food from that. I need something that will last a really long time and not pollute the soil.

Please note that the outdoor version of this is watered like any other garden, with a hose. So I don't need sensors or automation there.

But I am creating an indoor version for sell to people who live in places like Manhattan, where gardening is almost non-existent. But I need to know if there is anything in the system that might leech into the soil. The automation itself is actually quite simple- it's doing it in a clean way that is the problem. If I can lick this last problem, you can grow vegetables in your apartment with almost no effort beyond the initial setup. And no mess either.

Thanks for any help!
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TestGarden.jpg
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adafruit_support_mike
 
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Re: STEMMA Soil Sensor - I2C Capacitive Moisture Sensor Toxi

Post by adafruit_support_mike »

There shouldn't be any toxicity issues.

The part of the sensor that goes into the soil is standard FR4: glass cloth in epoxy, doped with a fire retardant called TBBA. You can find MSDS documents online, all of which say bascially the same thing: the dust can be a minor irritant, but there are no hazardous chemicals in reportable levels.

The soldermask and silkscreen are UV-curable epoxy inks, which are also nontoxic.

Given the amount of consumer electronic material that end up in landfills, toxicity and leaching are significant concerns for the electronics industry. The RoHS standards address ten materials that are known to have long-term hazardous effects, and our boards are made to meet RoHS standards.

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