# Different ways of designing a remote sensor to detect when a a glass container holding cooking spices is near-to-empty.

#### tinkerer88

Joined May 8, 2020
1
I do not have an engineering background, but enjoy building and tinkering with things. I am asking this question to get started in the right direction, and then I will seek out more specific engineering help (because this project is beyond me). I am gathering more specifics before beginning.
Goal: I am making a spice box organizer for myself. I want to make a system that can measure, remotely, when each container is near-empty, so I can refill it. And ultimately, I want a system so that I can have a container of 15 or 20 spices, and each is independently measured and then transmitted to a receiver. I am going to ask for help, but currently don’t have enough of a handle on the specifics in order to formulate the specific questions needed. Thus, I am looking for general feedback as to topics I should research more, or solutions that have been applied to similar problems.

My ideas thus far: Very generally, I could approach it with having each spice in an identical container (maybe test tubes), and having a way to measure the weight of each container over time.
Alternatively, having a sensor at a location near the bottom of the container, which will be able to detect when the spices have fallen below that level?
Or, having the containers arranged such that each is between an emitter and a sensor, and the amount of transmission changes when the spice level falls below that level?
I am trying to get a better handle on the possibilities of how this could be done, so I can better research it before beginning. At that point, I will seek out a specific engineer for help. But currently I don’t have a handle on how I should even approach the problem. Any ideas are appreciated!

#### dl324

Joined Mar 30, 2015
13,510
Welcome to AAC!

What you want to do is fraught with complications.
1. If you choose to measure weight, removing a container will trigger empty.
2. If you choose an optical sensor that measures level, removing a container will trigger empty.
3. If you use a sensor near the bottom, it can be triggered when the container is used.
What problem are you trying to solve?

#### ci139

Joined Jul 11, 2016
1,696
1. visual scan may pose the problem as some spices in a form of the powder(flour) - such as ginger , paprika , garlic , black pepper , ... may suck the moisture out of the air or stuck electrostatically to the container sides $$\leftarrow$$ but such can be done by detecting the large transparency threshold (but requires a uniform container or wasting a lot of time for calibrating for different cans and spices) . . . nothing's impossible , but that one may mean a hell of a lot work(time)
2. weighing needs a good calibration - you likely want to run it pulsed(interleaved) mode ... say - triggered by putting the canister back to it's place (such triggering is also a headache) . . . weighing also means you need racks on top of each scale so the cans won't share their weight to anyting else but the load cell or pressure sensor ($$\leftarrow$$i don't know how the output parameters of the least will change over time = repetitous impact and static pressure from cans . . .)

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#### OBW0549

Joined Mar 2, 2015
3,566
There's a simple solution to this problem: whenever you use a spice, note how much of it is left. When the supply looks low, add that item to your shopping list so you can replenish it the next time you go shopping. Problem solved, no electronics needed.

Seriously, this is something that is easy to do with your eyes and a little bit of common sense, and which will prove to be VERY difficult-- and expensive-- to do electronically.

Pick a different problem to solve-- one that actually requires an electronic solution. This one does not.

#### ci139

Joined Jul 11, 2016
1,696
there might be still simple solutions for seemingly complex problems once you spot what exactly to detect and how to detect it simply

... the problem that comes with getting "skilled" is that you know too many common solutions for the problems to become out with a non-common one