Vintage iButton Bling


Senior Member
I've always wanted this geeky iButton ring, a freemium from a Sun Microsystems conference in 1998. Somewhat rare, but still available for $20-30: Note these are 22+ years old with no guarantee of functionality. I just got a used one in good shape on Ebay and I'm pleased to report that a Picaxe can still read the serial number out of it just fine. Not sure if it's still writeable. Pretty sweet, since Picaxes can read them with a single READOWSN command:

Sun Microsystems' JavaRing, manufactured by Dallas Semiconductor, was introduced in 1998 at Sun's huge annual JavaOne Conference at the Moscone Center in San Francisco. Instead of a gemstone, the JavaRing contains an inexpensive microprocessor in a stainless-steel iButton running a Java Virtual Machine and preloaded with applets (little application programs) with a built-in Java Card 2.0 specification. Workstations at the conference had "ring readers" installed on them that downloaded information about the user from the conference registration system. This information was then used to enable a number of personalized services. For example, a robotic machine made coffee according to user preferences, which it downloaded when the attendee simply touched the ring to another "ring reader." Data was read from or written to the memory serially through a simple and inexpensive RS232C serial port adapter, which also supplied the power required to perform the I/O. The iButton memory was then read or written with a momentary contact to the "Blue Dot" receptor provided by the adapter.

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Senior Member
This Virginia company sells a variety of custom ibuttons. Here's a standalone temperature and humidity data logger:

Reminds me of a favorite manuka post: "There we go - the bones of a skinflint's single chip US$3 temperature data logger! Stan" from
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Back in 2010 I was doing quite a bit of experimentation with 1-wire devices and networks, see thread here:
I bought some devices from Chine ( via the *bay) and on receipt found that they did not have the standard “device type” as the first bits of the serial number.
They worked okay and my 1-wire device scanning program could find them.

when I contacted Maxim about the disparity in the “device type” to the documented standard I was informed that Maxim do manufacture components for some OEM companies that where the quantities are large enough they will create a proprietary version with a different “device type” as part of the serial number.


Senior Member
If you can pony up $7 for DIY E-bling, I recommend this digital watch kit. Comes with a 20-pin Chinese STC processor, but I'm sure a 20M2 version could be made to work.

Or if you're good with SMT, see
I have that exact watch, got it a while back when it was on sale, good product. You are a man of high taste, an aesthete. You really must have a pinky ring really would round out the ensemble. You are ready for any and all occasion.


Senior Member
Years ago I got a few temperature buttons and placed then in the chicken nests. I charted the data to see how much time each hen spent on her nest as she laid her eggs, incubated them, and then brooded her chicks. Fun project, but data is long gone.

I got them out a year ago and they were still working.

That's my ibutton story, and I'm sticking to it.