This is an archive of the original digital clock photos. The new clock has many improvements over the last one. It is much simpler to make as well, but does not include the alarms. The program that I had posted for the clocks also had errors that made it function in weird ways. As always, if you have problems, please post a comment to our site, and we will be happy to help.
The alarm clock pictured below is a pain to operate. It is also way too bright to be used in any room used for sleeping. The schematic for it is below. I’ll add the program for it for anyone willing to make it or make improvements on it! I know of some things that could be changed. Some things have been changed on the new design, like caps on the clock crystal and caps on the power supply.
Starting point: Make: Technology on your time (Volume 9, Page 134-137)
Digital Clock: Programming PIC microcontrollers, Part 3. (Opens in new window)
“AXE STACK 28″
Datasheets: DS1305 MAX7221 PICAXE 28X1
Advanced Clock Schematic (uses alarms, battery backup, does not work properly)
- Picaxe has a free program that you write your programs in and program your Picaxe chips. Find it here: http://www.rev-ed.co.uk/picaxe/
- Here is a complete list of BASIC commands for the Picaxe ICs. BASIC COMMANDS! This is a great learning tool. You can even start learning these in the Picaxe Programming editor before you buy chips with the built-in simulator. Learning these are a must for designing your own projects.
- Picaxe also shows you how to make a serial download cable so that you do not have to buy one, but if you do need to buy a download cable then get the USB version. You could also buy a starter kit. Buy it here: Hvwtech.com
If you are unfamiliar with etching circuit boards, please check out this article at MAKE. Click the ‘Subscribers – Read this article now…’ link and you can read the whole article. There are other resources that can be Googled.
How does Serial communication work?
a) Latch – (CE, CS, LOAD) A latch is used to let a device know that it is about to be spoken to and receive/send data. Think of a latch like a telephone ringing letting you know to pick it up and answer a call.
b) Clock – (CLK) A clock is used to synchronize data. Think of the clock as the tempo of a song, and the musicians (devices) use it to play their notes(data) at the right time.
c) Data In – (DIN, SDI) Data In is either the input pin on your microcontroller, or it is the input on the other devices. Think of Data In as the mouthpiece of your phone. You will send your data to the DIN.
d) Data Out – (DOUT, SDO) Data Out is either an output pin on your microcontroller or the output on the other devices. Think of Data Out as the earpiece of your phone. You will receive your data from the DOUT.