October 25, 2023
Description
This is a remix of my blood type keychain (see here). The design has been completely reworked and is now in the shape of a blood drop. The keychain has a size of about 30 mm x 42 mm x 3.6 mm.
The blood type of a person is printed on the keychain. A small NFC tag is inserted into the keychain during printing. Any information about the person can then be stored on the NFC tag. For example, I have saved the following information on my NFC tag:
In other words, the NFC tag stores important information for emergencies that is not on your identity card. I recommend not storing your address on the NFC tag! If the keychain with your keys and tag is found or stolen, they will know directly where you live. Not so good.
The information can be read by any NFC-enabled smartphone or tablet (or other NFC reader).
Note: Since blood group O is also known as 0 (zero) in some countries, both designations can be found in the files.
The following materials are needed for the keychain:
Generally, NFC tags with a maximum diameter of 25 mm fit in the keychain. Slightly larger NFC tags can also be cut to size, but please do not damage the wire of the NFC tag. I also cut the tag a little:
There are several apps for writing the NFC tag. I use the app NFC Tools from wakdev on my Android smartphone. This app is also available for Apple devices.
The following short video shows how to write the emergency information on the NFC tag. In the video you can see the first version of my keychain. It doesn't matter whether you write the NFC tag before or after inserting it into the keychain. The video shows the latter:
It is also possible to use the app to set up password protection against unwanted writing or deletion.
The NFC tag is inserted during printing. For this, a print pause must be added via the slicer software in the GCODE. The following YouTube video from Prusa 3D shows, among other things, how this is done using PrusaSlicer:
I also use PrusaSlicer. For the keychain, add a pause at a layer height of 2.20 mm (at a print resolution of 0.20 mm). Important: The print pause is done before printing the set layer, so the last printed layer is at 2.00 mm.
In addition, a filament change must take place during printing. The following are the layer heights for the different filament colors:
The print pause and filament change are already set in the GCODE files. The color change and print pause using PrusaSlicer are also described here:
2023-10-22: The keychains were slightly increased in their length and width (to 101.5 %). The height is unchanged. The dimensions of the keychain at the beginning of the description (see above) have been adjusted accordingly.
License:
Creative Commons — Attribution — Noncommercial — Share Alike
PhilippHee
