For those of you not in the know, an iButton, funnily enough, is not from those wonderful boys and girls who make the phones, computers, and seemingly everything else ‘i…’.

The iButton is actually made by Dallas Semiconductors.  If you’ve ever been in a bar, then odds-on, the barperson would have had one of these little things that they simply touch to the till to identify them as your server.  Yeah?


Well, Dear Reader, I’ve known about iButtons for years -we used them in the electronics department at Sheffield University for access control into areas that undergraduates are normally not allowed.

They’re dead cute, and can fit on any keyring.

But, the best thing about them is that each one is unique.  They have a laser-imprinted 64-bit serial number that is impossible to fake or hack (…they’ve tried, believe me…), so when you touch your iButton onto the piece of gear, it checks from a list of known users, and as nightclub bouncers are so fond of saying- ‘If your name’s not on the list, you’re not coming in!’

Same kind of thing, but without the badly-fitting suits or tattoos.

Well, to be honest, like the dreaded (no longer!) I2C that I mentioned previously, iButtons were things that I’d kind of been putting off for years.  In reality, they’re pretty difficult to program for, because everything is so dependent on timings and all other kinds of fun stuff.

The thing is, for the electric bikes to move forward, I needed a simple system -like an iButton- that regular riders could simply tap onto the top of the box, and it would instantly know who they were.  iButtons seemed ideal, but as I said, they’re a real drag to get right.

Well no longer!

Just a few minutes ago, with the help of my trusty feline (?!?), I finally cracked it.

As young Alfie so kindly reminded me from his position on my knee, the reason it wasn’t reading was that I hadn’t unset the bloody analogue inputs from PORTA, so it wasn’t reading it properly.

Well, now it is!

Now, the long-suffering Mr Ward Senior will not be around for our regular Sunday brunch tomorrow morning, so I’ve got all day to get the program working as I want.  Little things like the unit sensing when an iButton has been touched, interrupting what it’s doing, then reading the number from it.

Then I can program in the list of my six iButtons, so it will know exactly which one has been touched, and give an appropriate message.

All tremendously good fun, and it keeps me off the streets.

Oh, and there’ll be a ‘regular’ LEAF blog entry up first thing in the morning after I’ve processed all the photos and thought of just what to write.