This six-digit, beautifully designed timepiece showcases cold war era components — Numitrons instead of Nixie tubes — along with modern LEDs and a Microchip PIC to create not only a useful clock, but a great conversation piece as well.
1 – 1,000 µF/35V Capacitor
1 – 220 µF/50V Capacitor
1 – 10 µF/16V Capacitor
6 – 0.1 µF Capacitors
6 – 0.1 µF Capacitors SMD
2 – 12 pF Capacitors SMD
2 – 20 pF Capacitors SMD
1 – 1N5819 Schottky Diode
1 – 1N4001 Diode
2 – 1N4148 Diodes
1 – 1A Fuse
1 – PIC16F876A-I/SO Programmed Chip
1 – CD4017BE Decade Counter
1 – LM2575T-5 Switch Mode Regulator 5V
1 – SN74HC164N Eight-bit Shift Register
6 – CD4511BNSR BCD to Seven-Segment Drivers/Latch SMD
1 – ULN2803A Darlington Transistor Array
1 – Power Jack
1 – Two-pin Straight with Jumper Block
1 – Five-pin Angled
1 – 330 µH SMD Power Inductor
70 – UltraBrite LED 5 mm Purple, 10 Extra
6 – IV-9-Numitron Tubes
8 – 1.6K Resistors
5 – 10K Resistors
3 – 1K Resistors
2 – 15K Resistors
8 – 100 ohm Resistors
3 – Switch Long Tactile Button
1 – 4 MHz XTAL, Low Profile
1 – 32 kHz Watch-XTAL
1 – PCB
1 – 12V 1.5A Power Supply
Click Here for User Manual, Construction Manual, Full Schematic, Video of Clock Patterns.
I've started building my second clock and I wanted to pass on some lessons learned and mention that if you see SMD's and think they are too hard to solder don't let that deter you. Bill gives excellent instruction on how to solder the SMDs. I use a magnifying hood (2x) and that helps. Make sure you have a very fine tipped soldering iron. A microsoldering iron with a .3mm to .4 mm tip seems to work the best. Use small diameter solder and invest in a good pair of fine tweezers (Hako makes a good pair that can be found for around $5.00 on Amazon). The smallest components are the MLCC's (multilayer ceramic capacitors) and Bill's soldering method works flawlessly.
I let my clock run for 24 hours. It was synch'd, as closely as I could get it, to a GPS disciplined clock that I built, and at the end of the 24 hours the two clocks were still tracking.
Bill has answered a number of my emails and has been a great help. The problems were my doing and stemmed from having never programmed a PIC before.
The Mouser part number for the BCD to 7 Segment decoder (mentioned in my first review but I can't edit it) is:
The number I gave previously ended in BWSM. If you buy the kit there will not be a problem.
This is a fun and easy kit to build. It's well documented and worked on first power up.
Bad Mouser part number
Reviewed by Mike6158 on 10/27/2016
I ordered boards rather than the kit (didn't know there was a kit). I used the part numbers from the article. Everything is fine EXCEPT the 595-CD4511BPW BCD to 7 segment latch. The SMD's that arrived, with that part number, have a footprint that is at least 1/2 of the size of the component footprint on the board. The part number in the parts list is for a TSSOP-16 package, the board footprint is for a SOIC 16 device.
Note that the article photos reference a CD4511BCWM and the parts list references a CD4511BPW.
Again, the board footprint is for a SOIC 16 device which is the CD4511BCWM so the parts list is wrong.
The kit price is reasonable enough. One off, or in may case 3 off, boards are expensive. Ordering the wrong part because someone screwed up the parts list is expensive. Save yourself some grief and just order the kit.
Note to the author - Proofread your parts list... and thanks for a very nicely designed and documented project.