SD card locker (make true read-only SD/MicroSD)

Name: SD card locker (make true read-only SD/MicroSD)
SKU: 15723
Price: 12.00 USD
Availability: InStock
Rating: 4.37 (19 reviews)

(19 Reviews)

A small device that allows you to temporarily (or permanently) read-only-lock SD/MicroSD cards - V3

Designed by FairywrenTech in Latvia

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SD card locker (make true read-only SD/MicroSD) 1

SD card locker (make true read-only SD/MicroSD) 2

SD card locker (make true read-only SD/MicroSD) 3

$12.00

On A Break

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A small device that allows you to temporarily (or permanently) read-only-lock SD/MicroSD cards - V3

New in version 3

I improved my lasercut casing layer thickness+arrangement to make the resulting in-case SD locker thinner and more resilient.
I added a way to re-flash the SD locker through the SD card slot. It helps that the programming is done over SPI and that's exactly the interface used for SD card communications. Now, with a small adapter and USB-ASP, you can upload new or modified firmware into the SD card locker.
Keep in mind that first ~10pcs of v3 lockers were shipped with the reprogramming feature disabled because it wasn't clear whether it'd impact day-to-day operation - after testing, I determined that it wasn't a problem. If there's a 0R 0603 resistor right next to the ATTiny85 in your SDlocker v3, that means it's reprogrammable - also, any locker you buy now is going to be reprogrammable.

New in version 2

I redesigned the lasercut case to be thinner, making the "lasercut case" locker version less bulky. It's also now transparent, except for the middle layer which is transparent orange.
I added usage instructions on the bottom of PCB. They're readable on both cased and caseless lockers, since the lasercut case is transparent. If you ever forget how to operate this SD locker, just look on the bottom to get a refresher =)
I added a MicroSD slot on the bottom - it allows you to plug a MicroSD card in directly, without using any adapters. However, I haven't yet received my package with the MicroSD sockets compatible with the footprint I used, so, I can't make you a locker with a MicroSD socket - yet.
I reinforced the MicroUSB port soldering - in other products of mine, I found out that, if you apply quite a bit of force on the specific type of MicroUSB socket I'm using in the SD locker, it can detach itself from the board. I have contacted all the owners of v1 lockers, and this hasn't happened to anybody - regardless, I've added additional solder pads to the socket and redesigned the existing pads to provide more support to the MicroUSB socket. In other words, this version's MicroUSB port can handle much more abuse and will make your SD locker last longer.
The PCB now doesn't need any jumper wire fixes - so, it's cheaper for me to make these lockers, as I save a lot of time I can invest into creating new cool stuff =) Also, the caseless locker now looks prettier!

Why use it?

Make read-only Raspberry Pi SD cards
Make virus-resistant LiveCDs (or, rather, LiveSDs) for all your computer maintenance needs
Distribute SD cards with promotional materials
IT forensic research and data recovery (reading from the SD card while preventing all write operations)
Test your SD-card-powered products for unexpected behaviour (an SD card becoming read-only is a popular failure mode and tends to happen when the card controller detects severe data corruption).

How does it work?

Power the device through MicroUSB
Plug in the SD card - the device will power up
LED lights on boot for a couple of seconds, then shows the card's lock status (not lit = unlocked, lit = locked)
Press the button to toggle the card's lock state
By default, the TMP lock bit is toggled - it allows to unlock the card.
To toggle the PERM bit (and make the card permanently read-only), hold the button while plugging the SD card in - it will flash the SOS pattern on the LED (and won't proceed until you release the button). This is done so you don't toggle the PERM bit by accident, which irreversibly switches your card to write-only
Once you unplug the card, the device will power down. If you used PERM locking, don't worry - it will use TEMP locking on next card insertion (unless you hold the button again while inserting a new card).

Why does it work?

Larger SD cards have this mechanical "write protect" slide switch on the side, that you can switch and the card reader can check. However, that switch is more useless than useful, since 1) not all readers support it 2) the OS can ignore it 3) it obviously doesn't apply to MicroSD cards 4) the switch tends to slide accidentally (or fall out of the SD card altogether) when you have no intention of enabling write protection.

There exists a much more reliable method to lock the SD cards - the one this device is designed to use. The controller chips inside the SD cards (of all sizes, whether full-size or MicroSD) are required by the SD card standard to support a low-level command that locks the card into a read-only mode, preventing any changes - either temporarily (can be switched back to read-write) or even permanently (without a way to ever restore the write capability). This device has an ATTiny85 chip can send such a low-level command - this chip connects to the SD card, reads the lock status, shows it using the LED and allows you to toggle the lock status using the button. It supports both temporary and permanent SD card locking, too! Don't worry, I designed the permanent lock capability to be hard to trigger on accident.

Support

Full-size SD cards
MicroSD cards using a full-size SD to MicroSD adapter
MiniSD cards (anybody still uses these?)
SDSC (regular SD cards <2GB) and SDHC cards, there are user reports of SDXC cards working with my locker firmware, though I haven't tested it myself yet, it should work well.

ATTiny45 option

There's an option for you to get a SDLocker with ATTiny45 instead of ATTiny85 if you want to save a bit of money - the downside is that if you want to reprogram the SDLocker later to use i.e. a password lock firmware, there's no guarantee that it will fit in the ROM and/or RAM of the ATTiny45. However, it will work with stock TEMP&PERM lock firmware just fine.

Disclaimer

Each device is tested by me (on both SDSC and SDHC cards) before I send it out, and is designed so that you don't accidentally PERM-lock the card. Having taken these precautions, I do not take any responsibility for any SD cards you accidentally lock permanently, or any SD cards that may break as a result of using this device.

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FairywrenTech Shipping Policy:

Our post is reliable + you will get a tracking number! Use EMS (priority mail with a courier, will need your phone number) if you're worried about postal services on your end, or need your package delivered quickly. I ship packages on business days - otherwise it will just collect dust in the postal office till Monday -, and I'll prepare your shipment as quickly as possible. If there's any problems with your order, I'll get in touch with you through the email you have listed on Tindie and let you know how soon I can prepare your package for shipping, as well as ask any additional questions I might have.

Quantity	Price
1	$10.00
2	$11.00
3-4	$10.00
5+	$9.00

Review Breakdown

Average Ratings

Product: (4.53)

Documentation: (4.42)

Shipping: (4.21)

Communication: (4.32)

Keith | Oct. 8, 2024

Never received item, paid almost $50 USD

After messaging the seller yesterday for an item ordered in March of 2023 but never received, they then tried to spoof a server authentication error in an attempt to phish my email domain.

Avoid this seller. They are a worthless scammer and are attempting fraudulent activities via email.

Serenity | Aug. 14, 2023

Lovely bit of kit, this!

I do a lot of "hey, you know computers, what's wrong with my X" repairs for family and friends. I've had a Kanguru read-only hardware switch USB stick for over a decade now but it's getting long in the tooth being only 8GB and replacing them is, £50, £60 minimum for one.
For half the price *or less*, being able to toggle *almost any SD card* to be used for the same secure-from-virus shenanigans? Beautiful. I looked at the original project and making it myself was daunting - I thoroughly appreciate it being available to purchase! 10/10, highly recommended.

Edit with an update:
While using my original a defective cable (micro-usb retaining clip was bent straight up, didn't notice it at the time - bad eyesight) broke the micro-usb port off. I considered this no fault of Arya so I ordered a more expensive version with the battery capability included so that if it happened again there would be a redundant way to power it without very precariously holding the port in place (which did work btw!).
I let them know what happened just because I figured they'd be curious that it finally did (they stated on their page that they reinforced the soldering because it had happened in testing but that no customer had reported it).

My replacement arrived today. Not only did they include the USB C port on the battery version (I did not pay for this part), they sent me a USB-C and micro-usb version as a replacement for my broken one at no request from myself! I am incredibly happy with the customer service. When you're a small seller sometimes things mess up, especially when you're relying on international postage (the royal mail held this package for like 5 days with no updates), but they saw a problem that was absolutely not their fault and they still felt the desire to "make it right", in a sense. If I could add more stars to my review, I would.

Already locked and unlocked multiple microSD cards with all three of the lockers I have. One is important in my home security setup and two have different "IT Technician" tool loadouts for installing, diagnosing, repairing, all that guff. I want to reiterate that USB sticks designed for this purpose *start* at the cost of the most expensive version of this device, for a single USB stick, at 16GB. I've absolutely gotten my money's worth.

Stone | Aug. 3, 2023

It doesn't work at all!

After waiting for a long time (73 days, including 19 days after shipping at 2nd time with a tracking number) finally I got my item. It is very difficult to get response from the seller.

The case is not too bad - I can fix it by myself. Then I tried it (Version 4) with a 8GB Micro SD card. No matter the LED stays on or off, identifying the card is in temporary locked or unlocked status, I can add or remove files from the Micro SD card after!

Moreover, I ordered ATTiny85, but the one shipped to me is ATTiny45!

Very disappointed!

Stefan | July 8, 2023

works perfectly

This SD card locker is easy to operate and works perfectly.
The case does have a sharp edge near the usb plug, but nothing a few seconds with a file can't fix.

Ben | May 22, 2023

Works great!

Granted I have not tried the permanent lock feature as I don't want to do that to any of my cards yet. The unlock and lock commands work quickly, and as expected. It is nice, compact, and does the job. Having both micro-USB and USB-C is handy for easy connectivity. I'd be interested in buying a metal case if it became available down the road.

On another note. The first one got lost in the mail, but it was re-shipped very quickly once I was able to get a hold of the seller. Unfortunately this happened while the seller was away for a few weeks, and Tindie made it confusing as to if my messages were received, or just being piled up in a queue somewhere. Once their return date (according to Tindie) had arrived, Tindie still said they were away, and the return date just vanished. So I ended up making contact via Twitter instead to make sure the message got through, and that worked. Just a FYI for any others that have trouble with messaging a seller when Tindie says they are away. Tindie doesn't really make it clear how to deal with a lost package in those circumstances. I also didn't want to just force a refund for the missing item, and potentially harm the seller's rating before giving them a chance to fix the situation. That being said, all is well now, and I'm happy.

I would recommend the SD card locker to anybody else who needs such a thing.

Michael | May 15, 2023

Ordered product, Took money and ran.

EDIT #2: Product finally arrived on July 26th (ordered on March 25th). Still never received any communication from Arya beyond the public comment below. I've adjusted my review to reflect that he did eventually resend it and it did arrive, but still very very poor communications.

EDIT: Despite Arya's prompt response publicly (2 weeks ago), I have yet to hear anything as of June 2. I still must advise everyone to stay far away from this seller. I was really hoping it was just a misunderstanding...

I ordered this 2 months ago, and never received the product. The tracking information they provided both Tindie and I is invalid.

I tried emailing them directly twice over a week apart, was ignored both times.

I tried contacting them via Tindie's contact form. Also ignored.

I have purchased many things from Tindie without incident but this is just a bad seller! Avoid!!

Response from FairywrenTech | May 15, 2023

Heyo! Ouch, that's, not what I do! I've had a few packages get lost over the past few months' time, sadly. Checking through my Tindie inbox, I did miss your messages - looks like your order number was similar to someone else who I was helping find a lost package. My bad! Will assemble a new package and then contact you.

-Arya

Joseph | March 30, 2022

Useful Tool to Protect SD Cards from Alteration

I had been wanting the ability to "lock-down" SD cards in various scenarios and this devices does the trick! Cards have become so inexpensive these days that dedicating a few for a specific use is not so strange anymore. The vendor is awesome and helped me every step of the way. Good job!

Travis | April 25, 2021

Cool little sd locker. Works as advertised.

This thing is really cool. Our business sells digital products on sd cards, and by locking them we can prevent users from accidentally deleting their files. Good work!

Carlos | April 21, 2021

Fantastic Product!

I always wanted to make my raspberry pi projects "appliance grade". For me, appliance grade means the OS will be impervious to power outages. I configured the micro SD card as a read-only OS. However, I do not assume that a read-only OS cannot be broken into by a virus and made writeable. Therefore, I wanted additional assurance that the micro SD card could also survive virus attacks. The SD card locker creates another level of security because it operates external to the OS and closer to the hardware level. If the raspberry pi OS is compromised in any way, then a power cycle will return it to normal. Other uses will be for long term critical backup and offline storage.

I LOVE IT when someone makes a super-useful gizmo like this!

THANK YOU!!!

David | March 26, 2021

Does the job perfectly.

I ordered one of these to lock SD cards with presentations for our customers.
I was very pleased with the quality of the build and the fact that I can use it on the go.
It's a great product and I am very happpy with it.

Great job!

Anthony | Dec. 28, 2020

You want one of these in your arsenal

When I was debating on getting this, I really could not find a reason to need it. Well, my curiosity got the best of me and I decided that I wanted it anyway. The time it took for it to make it to my house was faster than some pieces of mail I send across the city (and this was coming from Latvia).

I have not really put it through its paces as of yet, but the instructions that came with it are clear and unambiguous. They flow very well and make sense. I have locked one of my older cards and it will now Rickroll people from now until the Big Crunch at the end of the Universe.

If you come across the same dilemma I had on deciding if I needed this or just wanted this, trust me, you need this. I am able to lockdown my MicroSD card that contains vital information. Such info that I cannot have it deleted and needed a backup to a backup that was firmly in place. DVD would not work due to size considerations.

Overall, the seller is making items that you cannot simply purchase. Toss the maker/seller some love and buy their stuff so they can make more stuff we will need.

Cheers!!

Constantin | Dec. 22, 2020

works great and instructions for usage are clear

Using this to lock SD-cards that contains keys for startup decryption of pcs (FDE), so people that have them don't get the idea to use them for anything else.

The locking and unlocking works perfectly and instructions are very clear. I did not try the permanent locking function, since that is not required in my use case.

The addition on having the instructions on the PCB is also very good since, If I don't use this for some years (which will probably happen) after the initial use I would probably not even remember what it is, and for sure not how to use it. Having the instructions right on there, you will never lose them.

Board looks clean and I can't find any fault with the solder connections.

I shipment happened very fast and I got a clear message with the tracking information. Packaging was good, the components were even sealed in esd-shielding bags, didn't really expect that.

If you order the adapter for reprogramming you get a SD-cards adapter that has wires soldered to it, that you than can plug onto the pins of your AVR programmer, I didn't test the reprogramming yet through.
It would maybe be a good idea to just put an SPI header onto the board, maybe that could be an improvement for further versions. But since it has none currently the solution of using the SD-card slot as SPI header is actually quite nice.

Ordering this here saved me a lot of time (and possibly money) by not making me acquire pcbs and all the different components to build it myself. Since the (very few) other commercial solutions that I found are way to expensive.

Travis | Nov. 6, 2020

Amazing Product

The Micro add-on is definitely worth it as it removes the requirement to carry around the Micro to SD card adapters.

Great idea is the instructions is apart of the PCB.

The device is useful if you have files that you want someone to have but don't trust them if they are going to delete them off the SD card then you can temporarily lock them.

Jurgen | April 23, 2020

I like this kind of stuff

Really, I like this kind of stuff!
For my work I hand out microsd's but I rather not see people use that sd for their mp3's. I mean, I am not giving away stuff for them to use it for other purposes.
So, I've searched until I found this little device. Small, handy and quick.

I had to wait a little longer before the device arrived but that was okay. I ordered it in the middle of the corona situation. I contacted Arsenijs (Tindie) he apologised and he even offered me to return or partially return my money (which I didn't think to be necessary. That's Service!

I only tried it on a SDHC (big memory card) and it worked great. I still have to try it with a newer SD (which I do not have yet).

Jurgen

Peter | Jan. 27, 2020

Very satisfied

Fast delivery, good description, good packing. I'm very satisfied with what I got and to what price.

Ahmad | Nov. 6, 2019

Simple yet functional. I'm a happy customer

Tested on sdhc card kingston. Its working well with temp_write protected.

Hope will do repeat order. Really appreciate it.

Thanks

Herbert | Nov. 6, 2019

Amazing SD card locker!

I ordered two of these SD-card lockers, and twiddled my thumbs for a few days until the package with the devices arrived.

I immediately connected one to a micro USB for power, and tested them on a micro SD card.
That micro SD card now has a song called 'Starlight' on it, until the end of its life.

The documentation of how it works is on the back of the device. You can't miss it, can't lose it.
The product itself is small and easy to transport.
A flashy sticker on the top side makes it easy to spot, but it's likely a good idea to keep that micro USB cable attached so you don't lose it.

The seller communicated clearly when the product was ready for shipping, and sent me a tracking code which greatly enhanced the precision of my anticipation.

Absolutely nobody you know has this device.
It is cheap, does what it needs to do well, and helps any company or mission that wants to distribute information in a non-networked way.
It's Christmas soon, just saying.

Response from FairywrenTech | Nov. 6, 2019

Hey! Thank you for your review! A small correction - at the moment, the documentation for locker use isn't actually printed on the back of the device, instead, it's printed on a leaflet that I put inside the package. However, to think of it, having it printed on the back of the locker itself (both on the PCB and on the bottom of the case) is a great idea! I'm ordering a batch of new, improved, SD locker PCBs now and will be building about 20pcs of these, and now it seems I also will be ordering documentation stickers I'll be putting on the bottom of the case.

Also, I don't think you should keep the locker with the cable plugged in (if that's what you meant by 'attached'). If you push a MicroUSB plug upwards/downwards with force while it's inserted into the locker, you might stress the MicroUSB port and have it eventually break off the PCB, rendering the locker unusable until the port is re-soldered - at the moment, you need to disassemble the case for that, so it's a hassle you'll want to avoid. I've noticed this problem a week ago when using these same MicroUSB ports on another product of mine - the next revision will have either a reinforced MicroUSB port or some kind of reinforcement built into the case. If you (or anybody else that's purchased a locker of this revision) have this problem, let me know your address (use the arsenijs at zerophone dot org email) and I will send a replacement locker at no cost.

Cheers!
Arsenijs

Gregg | Sept. 19, 2019

Does exactly what it says

Good communication from seller. It came when he said it would and works as advertised. Very satisfied.

K. Roland | June 12, 2019

Very satisfied.

A battery powered SD Card locker for setting the write protection flag in a SD Card or, with adapter in mini SD Card or micro SD card.
Perfect communication and perfect delivery. Thank you very much!

+ Show 14 more

$12.00