XSIID with LED / total writable?

Thank you for all the comments on my thread about using a chip to pay. That might be too much for me right now.

With the xSIID I can send data and get a light?

But how much data? 888 bytes is around 300 words or so? Isnt it about 3 bytes needed for a word?
So I could pass on my linked in AND a rickroll video? (linkedin and youtube video). Or a youtube video and a few lines of text (name, phone and email?).

1 Byte is one letter/character

You could fit two links and some text on the xSIID’s data size quite easily, though you’d probably have to play with the implementation to get the two links to scan the way you want. In other words, though you can put multiple links on an implant, usually only the first one will open automagically


Thank you! So I get 888 bytes total? Which would be 888 letters. So one link that will autorun…and then some text? Do I have a say on what opens that text or where it goes on their phone? I assume the default app on the phone would open the text? Thanks!

Eh, sort of:

Let’s imagine an example tag with the following records on it:

  • A video link
  • A social media link
  • Some Text
  • Your Name

If you scan this tag with a phone, it will automatically open the first record, in this case the video link, and to access the other records you would need to scan it with an NFC app to look at them directly (Or use an app set to open/look for specific records like Tasker)

You get to chose what that first record is, but only that first record will auto-run. I don’t know off the top of my head what happens if you scan a tag with a text record in the first slot, my guess is it does nothing and asks you to select an app to use with the tag


You can also increase the functionality to more use cases by setting up a short cut on your phone so that it automatically performs a different function. Currently I have mine set up so that if I use my phone it opens a link tree URL with all of the web pages I use most frequently. If the chip is read with someone else’s phone it serves them a V-Card. If I open it with an NFC app I have all the stored personal info and it also opens my house and workshop.

Four discrete use types coexisting on the one chip. With an LED as the cherry on top!

You’ll luurrrve it! :crazy_face:


I do love the idea :slight_smile: , but am getting lost on whose phone is whose in what you describe. Just to verify I can set this up so “thier” phone opens a Vcard when they scan my chip?



Scanned with your phone = Function determined by shortcut
Scanned with their phone = VCard (achieved by making it the first record on the list as described by Aox)
Scanned with NFC app on your phone = View all the records you have placed there
Scanned with certain* entry systems = Access to buildings etc
Scanned with any of the above = LED shines

This takes advantage of the fact that your phone will execute a shortcut before working down the list, whereas anyone else’s phone will be fed the first record on the list.

*Please be aware that the implantable RFID transponders that you find on this site work with one of two frequencies: Low (125kHz) and High (13.56MHz) and using a range of different protocols. The chip in the xSIID is HF and uses a protocol that is easily interrogated by smartphones, making it ideal for the uses listed above. However, entry systems use many different protocols, many of which are LF. If your main purpose in getting a chip is to clone your office access badge, you would have to find out the specific frequency and protocol used in that system.


This is EXACTLY what I needed, thank you!

No, I don’t have any need for access, so your description above defines the usecase for me perfectly.


Great! If you do go ahead please let us know how you get on. :emoji_thumbsup::sunglasses:

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Thank you, I will certainly post here when I do.

Do you find you accidentally key a scan of your phone while just handling it normally? Or is the range so minimal through your skin that you don’t? If on the back of your hand I assume handling your phone normally in the front of your hand would not key a scan…


No, the antennas are small so scanning is very close range. In fact it is normal to have the opposite problem, not being able to get a good scan, until you get the knack and know the correct angle and position.


Nice setup! It’s easy to focus exclusively on what the chips themselves can do, without taking phone shortcuts into account. I have an Apex Flex and the applet I use most often is OTP with the YubiKey Authenticator app, but I also have an NFC share installed with a VCard. Since there’s no point in me viewing my own VCard, I configured a shortcut to open the Authenticator app, which is in turn set to scan for OTP upon launch. Saves me a couple taps. :wink:


Exactly! The VCard is such a great function for everyone else while being of absolutely no interest to us.
You’re right about focusing too much on implants. Some functions can be delegated to external chips. I have NTAG stickers on the dash of my car that, again through shortcuts, set the phone’s SatNav to take me Home/Workshop/Jobsite. I also have one on the side of my bed that I tap to set my phone to turn off the audiobook I’m listening to after 15mins and set the alarm clock for the next morning.
All useful functions but not enough to merit space on my implants.


Yep! I have stickers to turn off Wi-FI when I go to work and arm my security system, but for some reason it never crossed my mind to do something similar and assign a phone shortcut to an implant.


it may be worth mentioning that storing a vcard as an ndef record means anyone with an iphone who scans your implant won’t get the vcard because iphones refuse to accept vcards over ndef.

you can counteract this by creating a vcard file on a service like vcardmaker and hosting that file and using a URL to point directly at the .VCF file.

“but but then everyone would need wifi to get your contact card” nope just the iphone users.

if you put a vcard as record 1 and the link your hosted vcard in record 2, android users will be able to natively accept your vcard and iphones will iterate through the records until it finds a compatible one, aka your hosted file on a URL.


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I did the same on the inside fairing of my motorcycle :+1:
Pull phone out of pocket, scan tag and clamp to dash.
Combined with RFID starting system makes a smooth start

Unless you have URL in your card then those will pop up

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what? thats what i’m saying. put the link and the vcard so both users can read your implant.

If your vcard has a link, it will open the link in the vcard.
my vcard has several website link and the iphone open the first link on the record

oh yeah that’s what i’m saying, it auto launches the file in the contacts popup so you can quickly click add. super efficient im surprised apple is so cooperative.