Keep Fun In Check With A Parental Count Down Timer

Gaming industry software engineer [Pedantite] writes in to let us know about his latest endeavor, an AVR based parental assistant timer: Good Times.   Looking for a new project that would be both useful and interesting, his wife suggested a “time out/ time’s up timer”. Like most of us [Pedantite]’s children are well studied in the arts of procrastination and mischief.  In the kids’ case this leads to time outs and break time running amok. The solution, in this case, is pretty much an advanced DIY egg timer with fun sounds.

The timer sports all of your basic countdown-timer functions including a 4 digit 7-segment LED output display, stop light style LED indicators, and controls to start/pause and stop the count down. The count down time can be input via the +5 minute, +1 minute, and +15 second buttons. There is even a happy/sad button to toggle between “time out” and “break time” modes. Two Atmel micros power the device, an AT Tiny 2313V for the capacitive touch keypad and an AT Mega 644P for the display, audio, and time measurement.  There are a lot of excellent techniques used in the build, some which we have covered here:  Four 595 Shift registers for the display; A 4 bit r2r DAC for audio output.

[Pedantite] is still in the process of writing up the project in multiple posts, and would love to know what you all want to hear about. Check out his blog for details and a quick video of the timer in action! Also, if you are interested in capacitive buttons, check out part 2 of the writeup.

Capacitive Buttons Control All Life

capacitive_game_of_life

Projects involving Conway’s Game of Life and utilizing a Nokia 3310 screen are quite popular with electronics hobbyists. [Droky] put these two together and went one step further by adding capacitive sensors to control the Game of Life. His work is a great example of how to use the Atmel QTouch capacitive sensor (QT100a datasheet). This chip does the heavy lifting that we’ve seen in other touch sensitive solutions. It operates from 2V-5.5V, requires only three capacitors and a resistor, has a one pin active high output, and sells for around $1 in low quantities. One thing [Droky] overlooked in his board layout is the ground pad on the bottom of the WSON6 chip. He was able to make it work by masking the trace that runs under the chip but you will want to alter the layout in your own designs.

If you’ve used the QT100a before we’d like to hear about your experience, and find out if button debounce handling is necessary with this chip. Let us know in the comments. You can see a video of it in action after the break.

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