24" Wall Clock
tour de suisse shup up scooter aprilia top class escort yoshi torenaga www polaritalia radeon 9250 vivo foto porno mesturazioni nf4 sli diamond fotocamera usata js technology nu i il super cofanetto di columbia romania mp3 lancia musa km 0 co behringer xm8500 epson stylus 460 giochi di ping pong obbligazioni quotazioni immagini nike flight simulator 2000 schede usb coppia dassi newcastleupontyne d70s 1gb ultra mamiferos sony fs195vp mazzucchelli rag against the machine merchant account incontri amatoriali gratis libri meccanico navale 1 classe speciali toshiba modello mk4025gas logitech stealth pelletier hajmo bosno por ti yo podria morir gay sesso gay maturi in veneto jugarjuegos ragazzo fidenza salaparuta hector y tito en vivo lop julija carraresi banca cermenate notebook asus 3000 sddd fernando botero heilbronn pneumonia libertango astor try nelly furtado il testo screensaver hello kitty traviata libiamo ne canzoni tiziano ferro siti amatoriali di coppie vere km o www s paolo net lg lcd dvd xd picture card da 512mb lcd digitale terrestre foto sexy di veronica rega star sailor gabetti it nude kameron kn 200 sexi calendari theme desktop ais alive proxy 45 sketches kisses the rain chitarra zen hande yener tr marx it titolo esami maturita 2004 ozone dage lovely sara princess sarah vol 01 mature and boy gay dinnanzi a noi il cielo nokia 6600 italia route 66 mobile 2005 max payne2 no cd longitude latitude le dodici pistole del west volante parlante stefani video foto di montella calciatore jewish dating inno della marina salara www iranvajahan net forget her elenco telefonico pesaro grupo aventura britney spears nude giorgio e stefy negozio di scarpe de noche en la ciudad gaping punto 12 bool would you free books download dvx hotel di pescara maglieria armani minero registratore ingresso microfono triband nokia cellulari vendita immobile varese sex sat com atk hair more pentium 3 s videoproiettori epson s3 fondi italiani martinho da vila fresh clean octopus tecmo bowl lully bando lauren jackson nude immagine discoteca salvadores www shg it belkin adsl wireless il profumo j adore led fan 120 nero 5 masterizzatore esterno usb 1 1 applicazioni per lg 8380 dividido san vito dei normanni quiereme besame toschiba de republica amarone quintarelli giuseppe vendita dvd imperia strumenti musicali usati bracciali da uomo inviare sms con computer schede madri asus intel buitres il sito ufficiale del grande fratello pentium m intel boxed brionvega televisori motorola d470 run time 0701 olympus fotocamera 370 www provincia treviso it catechine philips 170s6 andrade antonio de hunt james henry leigh fotocamera digitale nikon coolpix 4600 aston martin milano sherlock holmes e la perla della morte happy christmas spartito koochy cucina alice mp3 nederlandse muziek alimentatore 12 volt aim download stars on 45 beatles warren zevon ati 3100 listino prezzo scooter lettorimp3 apple hyundai coup 1998 cadillac sts ciclista morto thinkcentre a51 fuck women vree my love ghost stampante laser samsung color alfa romeo 75 turbo annuncio incontro perugia p pio na canzuncella doce doce avv barone vittorio le carte yu gi ho teach my ass pioneer cdj 800 terremoto in giappone auto usate perizia e valutazioni gratis monitor benq 937 bumper karts only hpoe tomassini risultati test medicina messaggio nella bottiglia seat ibiza 19 tdi sport digicom home 54 belli come u touch my ta la la orologi da muro polar s720 keycode seca italy anthem risultati esami maturita 2004 lettore dvd dvx vcr quan ero piccola ram kit princess di recorder dvd amstrad mule it wharfedale diamond 9 1 foto di trieste tru tones castle attac 2 hotel durban archos gmini 402 obbligazioni tiscali caprarola fbi cape canaveral tapis roulant hp esami avvocato catanzaro esiti fiat punto 1999 cabrio samsung scx 4216f volo boston secret top spartiti musicali mina campeggio frigoriferi da jeeg robot mandi burewala vita da artista samsung sgh scarpe birkenstock dect gap telecom custodie ipod la moglie infedele sistema babilonico commodore64 cartucce stampanti epson lebt denn pc phone panasonic dvd tv box terrestre restuarants ricevitore satellitare telesystem sat {| align=right
|-
|
|}
Clock Control
Who wants to set the real time when we've got GPS to set it for us?! :) I am going to use the Lassen iQ to get a time lock and use a couple buttons to get the local time from that.
We need to control 23 channels 18:88:
- 1 has two segments, but the entire number is either on or off
- : is always on, but we may way to flash it for seconds
- 888 21 channels
I decided on 25 channels just in case I need some extra ['flare']. Perhaps an alarm of sorts. 'Beer Time' alarm at 4:30pm? We've got to keep our options open...
The need for 25 I/O pushed me towards the PIC 16F877A:
- Easy to program (I've got a big code base)
- Has enough I/O
- It can be bootloaded!
- It's got an RTC (when you add an external 32.768kHz xtal)
- UART to read the incoming GPS NMEA from Lassen iQ
ToDo : It's possible to reduce the number of channels by multiplexing. A gain cost is also possible by multiplexing digits, less cm2 of board, less expensive components, less comsumption. 7 segments x 4 digits (remenber the 24:00 time format from 00:00 to 23:59) = 4 channels for digits and 7 channels for segments = 13 wires 1 for ":" 4 for extensions = 18 wires. Some other components like CA3161 (bcd to 7seg) can also reduce necessary wires on PIC for displaying about 4 4 1 4 = 13 wires.
Light Control
Well if the PIC 16F877A has got the timing and control down, how exactly do we turn on/off the light stick?
Since the sticks only pull 60mA, we can use cheap BJT transistors. Let's go solid state! Many itty-bitty SOT-23 SMD BJTs can handle up to 1A with a max input of 40V. The maximum power output is 350mW though. Luckily, when forward biased, the MMBT2222 has around 0.5V drop.
So 60mA with 0.5V drop, we are looking at 30mW dissapation. That's atleast in theory. I'll believe it when I see it of course. For the time being, I'm going to assume this will work...
All I need is an NPN BJT for each channel:
While this should work, it's going to leave a bunch of connections with one pin 'hot'. A better design would probably utilize a PNP connected to RAW. Ehh - no big deal.
If you're planning to use a beefy light source, like Neon or super powerful LEDs, you could easily use the same setup to control a relay. Relays can handle 5-20A in some cases, are relatively cheap, and sound really cool! The only problem is they are big. And for this project, we wanted a relatively small control board. The next rev may use beefy 5A relays to toggle all sorts of potential snazzy light sources.
Board Layout
The PIC is connected to 25 channels, the GPS, a couple buttons, and a status LED. Here's the current layout in all its random glory:
You can see it's a bit dense, but the polarized two-pin connectors should make it easy to attach the light sticks. Everything was SMD to ease the assembly as much as possible. It's much easier for us to do solder paste with a stencil and SMD devices than it is to bend 25 resistors and solder 25 BJTs into place, then clip all the leads. PTH is actually pretty time consuming. I digress...
There is a switch to multiplex the PIC's RX UART inbetween Debugging and listening to the GPS unit. Be sure to use Port 2 on the Lassen iQ if you want NMEA output (4800bps by default).
Things to Improve
Nothing at the moment. We have to wait for all the parts to come in. Should be about 4 weeks.
We may need a cover on the light sticks to give more of an opaque presentation. TBD.
Documents
SFE Wall Clock Main Board Schematic
Footprints:
SFE Footprint Library
FP Name: All sorts of FPs used.
Supplier Info:
Related Items:
