Saturday, October 20, 2012

Relative Clock/Timer/Alarm

Introduction 

Towards the end of the '80s, when I started out in electronics, one day I decided to make a special alarm clock: one, that, when the time comes, switches on some device in my room - be it a radio, TV or anything else. At the time microcontrollers were not easy to find and I didn't even know how to deal with them anyway, and so I decided to make this circuit out of TTL chips (74xx series). To make it easier (and also to raise its geek factor quite a bit :-) ) I decided that the clock should not show the actual time and the time the alarm is set to, but to show the remaining time to the alarm event. Since I needed the alarm for the same time every day (for school), I quickly learnt to convert it to actual time.
The fully assembled unit - missing some decorative items after having been kicked around for the last 20 years...

Monday, October 1, 2012

TV Auto-off from the '80s

Introduction

In the eighties most TV sets did not have the sleep function that is standard on today's TVs. My grandfather was known to fall asleep about 5 minutes into watching any program on TV in the evening. Then, the TV would go on all night long. Those TVs in the eighties consumed a lot of power, so one day I decided to make a small device that would automatically switch off the TV when he falls asleep. Also, this device had to be very simple to operate so that grandpa wouldn't have to attend a course just to switch his TV on and off...