The project is that I have a box with objects in it. Each object has a placeholder within the box. I want to place a sensor in the bottom of each placeholder and have it tell me if an object is within the placholder or not. With RFID i want to know what is missing without opening the box.
Looking for a sensor that is small (size of quarter), uses passive rfid technology and will tell me if something is touching it. Possibly just store a binary value if something is touching it or not. Looking to be able to stick the sensor ina location and know if an object is touching it. The read range can be short or long. What type of tag would I be looking for? Willing to discuss the option to have it created for a fee.
Love to hear the groups thoughts
I guess it would make more sense if I explained the complete use case.
I have a plant store. Within the store I have 30 cabinets. The cabinets hold trays of plants. The plant trays differ in size and they slide in and out of the cabinets. There are 50 slots within the cabinet. A tray can slide within each cabinet at any of those slots. I want to place a sensor on one of the trays and when i move it in and out of the cabinet it will update my database and let me know where it is. The trays will be constantly moving from cabinet to cabinet depending on where the plant is in its growth cycle.
Once I am able to determine the distance the tray is from the reader on the cabinet I can associate the distance to match the number labeling system on the cabinet so i will know exactly what slot the tray is in.
Automation is the complete goal.
That is goal. I want to place a 'tag' on each device that goes into the cabinet. Not only do i want to know the object is within the cabinet but i need to know where its mounted within the cabinet. When the cabinet is scanned for objects it would return what objects are in the cabinet and their location on the Y axis only. Im only concerned about the objects height within the cabinet.
The goal would be to have hardware on the cabinet that would be able to inventory all objects within the rack. I think ultrasonic would not be applicable in my scenario.
With ultrasound, will there be issues with the pulse traveling through other objects within the cabinet until the pulse hits the tag?
With the max distance a signal would travel being 8ft, would the continuous wave method work?
The basic idea is this...
I will have multiple cabinets next to each other in a room. Each cabinet will have a sensor located at the top. Within the cabinet will be multiple other sensors at different heights located on shelves. I want the sensor at the top of the rack to be able to locate all sensors within its own cabinet and also determine the height of each sensor.
Im not concerned about its exact position in the cabinet, only its height. I figured it would be easier to accomplish this by placing a sensor at each cabinet instead of using triangulation with a few sensors within the whole room. This could also help make the margin or error smaller, hopefully down to half an inch.
What do you think would be the best way to measure the distance to determine the placement of the sensors height (Y axis)?
@tbowmo Maybe i missed it but do you have an image with the si7021 attached to the radio and pcb?
I apologize for the questions and how simple they may be, as Im new to this community but very intrigued with the creativity and endless possibilities.
Wow, very impressed with your design and how you got the radio mounted directly on the sensor. This is ideally what Im trying to do and apply a battery that will have the smallest footprint possible.
Ill take a closure look at all your steps provided.
Do you foresee a setup that can mimic this using the atmega?
I too got mine from Mouser.
I plan on trying multiple battery configurations. I will keep you updated on my results.
Questions about the configuration and setup, sorry a bit new to this. I should be fine with just connecting the radio, atmega, and the si7021 together without having to worry about attaching a regulator because all are able to operate that the 3.3 correct? Or do I need to prepare the sensor to work down to 1.8v?
Where did you pirchase your si7021?
Its really a loaded question I know.
Being able to replace the battery may be an option, ideally i would like to avoid it.
Thanks for the advice. I will look at that option.
What type of data polling frequency do you plan on using?
What type of batteries have you looked at?
I ideally would like to be able to change the polling frequency but so far I can think of maybe 1 minute to 10 minutes is what i would like to do.
Does anyone have any insight into a battery size that will provide the most bang for your buck and be the smallest size possible? Im going to be creating temperature sensors and need the sensor to be as small as possible.
I guess I should first build out my prototype then address this "concern." My setup will be a wireless sensor that will collect temperature and humidity. The goal is to have that sensor as small as possible. I plan on creating a few types that all have different size batteries. I from then will need to see which size gives me the most battery life for the most temperature readings. I from there will need to configure a controller to receive all that information. Here is my current idea:
Do you think this configuration will provide me what Im looking for?
Once I get this setup working i will test antennas on the configuration to test the length.
@daulagari I guess I should first build out my prototype then address this "concern." My setup will be a wireless sensor that will collect temperature and humidity. The goal is to have that sensor as small as possible. I plan on creating a few types that all have different size batteries. I from then will need to see which size gives me the most battery life for the most temperature readings. I from there will need to configure a controller to receive all that information. Here is my current idea:
Do you think this configuration will provide me what Im looking for?
Once I get this setup working i will test antennas on the configuration to test the length.
Is there a way to enable the controller to be the one that searches for the sensors?
This would allow for the sensor to be smaller by having the large antenna be placed on the controller.