Thought this would be interesting to look at: The iButton 1Wire 64bit ROM

[Bobertsawesome]

I went to replace a battery in my AstroPhysics remote control and found what looked like another battery that would need replacing. To my shock, it wasn't a battery at all, in fact, it was a type of serial key/unique id system, all contained in what looked like a fat button cell. Doing some research on it, I found that this was pretty advanced for the time (MFG date 2004). I thought this would be interesting enough to share.

From the mfg:

The DS1990A-F5+ provides a guaranteed unique ID in a small iButton® form. This iButton can be used as a key in access control systems, inventory control applications, work-in-progress tracking, or other applications that require a low-cost, reliable method of validating identification.

Note: These images below pertain to a different model of iButton, but probably the same construction.


https://www.cl.cam.ac.uk/~sjm217/projects/ibutton/

[ArthurDent]

Around the mid 1990s the company I worked for used these to uniquely identify units on a production line. One of these was paired with each unit until it got through final test. They were then reused the next day.

[coromonadalix]

Do i see a small coin cell inside the ibutton ?? i tought thes ibuttons had a parasite supply mode ?

[todd_fuller]

Depends on the model. Some are just crypto authentication or unique serial numbers while others log temp, humidity, etc.

[ale500]

I worked with them mid 90s, we had developed an application based on the DS1994, they had a lithium battery in them, because they had an RTC. They were called "Touch memories" in those times... Pretty neat devices with internal RAM and RTC and scratpads.

[Bobertsawesome]

I worked with them mid 90s, we had developed an application based on the DS1994, they had a lithium battery in them, because they had an RTC. They were called "Touch memories" in those times... Pretty neat devices with internal RAM and RTC and scratpads.

So neat to hear about the past uses. I'm 20, so I grew up in the age of pushing Moore's law to its limits, I didn't get to really analyze the neat things coming out early 2000s. I can only imagine this was really high spec stuff that every company wanted their hands on. I think in this AP Keypad it's the device that holds the authentication data for the software, because back in the day this was the bees knees for telescope mount control. It still is, but the use of devices like the SkyFi where you can control movement with your iPad/iPhone has surpassed it. They were most likely really concerned about reverse engineering.

Heres the keypad in question: