== Circuit ==
* A discrete astable BJT multivibrator feeding into a johnson decade counter74HC595 shift register, which drives the LEDs directly.* The counter shift register can serve up to 10 8 segments.* The LED matrix can partitioned partitioned arbitrarily column-wise: multiple columns can be grouped onto a single counter output.* each counter shift register output has one series current limiting resistor* last multiple display modes:** blink (unusedCLK goes into enable) counter ** fill slowly, clear slowly (last output inverted feeds back )** fill slowly, clear at once (last output inverted goes to reset)** rotate (last output feeds back)
* multivibrator speed can be adjusted with a pot
* on/off switch?
* LED, $0.04650 @ 1000: http://search.digikey.com/us/en/products/WP710A10SRD%2FD/754-1593-ND/2769819
* CD74HC4017 decade counter, CD74HC164EE4-ND $0.4776 30994 @ 50100: http://searchwww.digikey.comch/usproduct-detail/ende/productsCD74HC164EE4/CD74HC4017ECD74HC164EE4-ND/2961506713* DIL14 Sockets @ 100: http://www.digikey.ch/product-25989detail/de/1-5390261-3/A100205-ND/4803171125623 (Easier to change the IC if you kill it (wrong wiring, wrong polarity may kill the IC...))* 100nF (long leads) Capacitors @ 100: http://ch.farnell.com/multicomp/mc0805224z500a5-08mm/capacitor-ceramic-0-22uf-50v5v/dp/1694344 (Pour le découplage de l'alim près des IC, à monter sur les sockets)
* CR2032 holder, $0.4968 @ 100: http://search.digikey.com/us/en/products/3003/3003K-ND/227448
* Pushbutton, $0.0916 @ 100: http://search.digikey.com/us/en/products/FSM4JH/450-1650-ND/1632536
* Pot, $0.3197 @ 100: http://search.digikey.com/us/en/products/3306P-1-105/3306P-105-ND/84994
* Jumper, $0.04516 @ 500: http://search.digikey.com/us/en/products/NPC02SXON-RC/S9341-ND/2618266
* Male header (36 pos), $0.62350 @ 100: http://search.digikey.com/us/en/products/68000-236HLF/609-3465-ND/2023290
* PCB 5cm x 10cm, $1.498 @ 50: http://www.seeedstudio.com/depot/fusion-pcb-service-p-835.html