projects

Dutchtronix AVR Scope Clock

Thursday, 20 September 2007

This Scope Clock was designed by Jan de Rie, and built from a kit available from his website.

The circuit uses a ATmega168 micro-controller, and a TLC7528 DAC. There is also a PCF8563 real time clock with battery. The clock requires a 5v power supply.

There are several display options (selected in Menu Mode), such as analogue only, or showing fewer numerals.

Jan has a ton of documentation on his website, such as:

•AVR Oscilloscope Clock Assembly Instructions

•AVR Oscilloscope Clock Operating Instructions

•AVR Oscilloscope Clock Manual / F.A.Q.

•AVR Oscilloscope Clock Schematics and PCB

I also have some more pictures posted here...

The clock, which connects to any analogue oscilloscope (in X-Y mode) using regular 10x probes, produces the clock face and current time display as shown left. A Menu Mode and RS232 interface allow the user to set the time, date, and or other options. The time and date is retained with a RTC and battery when power is removed.

Mac's and the Serial (RS-232) Interface

The clocks RS232 interface works perfectly with OSX and a KeySpan serial/USB adapter. Infact its very easy to set up, and there's no additional software needed.

The procedure is as follows:

1. Open an OSX terminal session (window)
2. Identify the right TTY device name. Type:

ls /dev/tty.*

with the KeySpan adapter plugged in, you'll get a list, including something like this:

/dev/tty.KeySerial1 /dev/tty.modem

The device "KeySerial1" looks pretty obvious!

3. Then type:

screen /dev/tty.Keyserial1 19200

4.Type "xs", or "xh", and the clock should respond as you expect. See the OSX screen shot .
5.To quit the screen app, type control-a, then control-\.