Looking for a Memory Chip to go on a reader card to store information ?
Hello, I am a non IT person and looking to indentify the best way to produce a storage chip. It could download the basic information from a computer source or maybe instal a template of a pro-forma and the owner would instal the information on the form...... It would go onto a chip card and be able to be updated and changed from time to time. The chip card could be read through a reader and onto a computer.
Have I explained my enquiry very clearly ? If not please let me know what other information you require. Thank you. Alan.
p.s. I have looked at Static andom-access memory but understand that this looses info when a elec source is terminated !!! Can you advice a suitable chip that could work please ?
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Three types of memory hold data even after power has been removed.
ROM (read only memory) had the data determined at time of manufacture, and can't be altered or updated. This wouldn't work for your application.
EEPROM (Electrically Erasable Programmable Read Only Memory) is usually limited in storage capacity, but has high endurance cycles. (It can be rewritten many, many times, and holds it for a very long time.)
Flash memory is similar to EEPROM, but can store larger amounts of data. The trade-off is that it can't be rewritten as many times as EEPROM (thousands of times for Flash, vs around 100,000 for EEPROM) and may not hold the data reliably as long as EEPROM (10 years vs 50 to 100 years) without being rewritten.
So the decision for you would depend on how much data you need to store, vs how reliably you need to store it. Less data very reliably -> EEPROM, more data but not changed as many times and not for as many years -> Flash memory.
All that said, this is a case of don't re-invent the wheel. There are plenty of memory chip cards out there, manufactured in huge quantity, with extensive engineering already done as to the manufacturing methods and interfaces for reading/writing.
Interfaces are either electrical via a set of contacts (like bank chip cards, cell phone SIM cards, SD flash and Micro-SD cards), or radio frequency (RFID, or in some cases, WiFi or bluetooth).
Some chips can do both - RFID for being read by an external reader, but with an electrical interface for direct connection to a micro-controller in the same package.
The chips also vary in the extent of security. Some have built-in encryption capability (important for bank cards, not very important for children's toys). Some of the ones with encryption also have anti-tamper features, to help thwart attempts to bypass other safeguards.
So your decisions come down to:
How much data do you need to store (a few bytes of ID number at one end of the range, to a life-long diary in the gigabytes at the other end of the range).
How many times will the data change over the life of the card?
(Very few for an medical records, vs many for a copy machine access card that stores the number of copies made on the card.)
How long does the data need to last? (A card that expires every year, vs a long-term ID or emergency medical info card.)
How secure does the data need to be? (Storing data for convenience or a children's game, vs banking or private medical data, vs nuclear launch codes.)
Does it need to be read without physical contact? (ID badges for opening a door with your hands full, or product ID on packages passing by on a conveyor, or pet ID chips embedded under the skin, all relatively short distance) or highway toll cards readable from tens of feet.
What physical size constraints do you have? (The pet ID chips sealed in a package the size of a couple of grains of rice, chips thin enough they are embedded in a plastic credit card, or highway toll card where it doesn't need to be particularly small and you don't want to accidentally misplace it.)
How fast do you need to update the data on the card? (Slow for an ID card, very fast for cards storing video.)
Off the shelf cards like microSD are small enough they can fit in adapters for the older SD card standard - which itself was not that large to begin with. So even if you want a non-standard package for your product, you might use a standard memory card inside your package.
RFID cards / tags are available in a number of form factors, from grain of rice size for pet ID, to key fob, to size of standard credit card, to book spine, to plastic coin-size shape.