Wednesday, September 29, 2010

DIY hard drive clock (intro)

Hard drive clock. New life for old junk.

Technical idea is pretty old but making things is fun and hard drive clock itself is very cool and entertaining device.
It's quite easy to build one and I'm sure that most  DIY-makers have some unwanted PC hardware that can be easily put into service again.

Obsolete hard drives. Are they good for something?
Beside hard drive itself, for this project we need microcontroller, real time clock, photo interrupter or Hall effect sensor and bunch of RGB LEDs. All this stuff is widely available. 

Wednesday, September 22, 2010

DIY laser spirograph (part 7)

PIC18F1320 based controller for laser spirograph. Final release. Ready for order.

Well, I think, prototyping stage for laser spirograph project is over and it's time to release final design for DIY community.
For final controller I've ordered factory-made double sided PCB with lovely green solder mask (people always wonder why my home-made PCBs are not green ;-))

PCB fabricated by Futurlec

PCBs are made by Futurlec. It's my first order from this Thailand based company and I'm quite happy with quality of work and service. Lead time is about one week. There's no minimum order but price is really good if to order in quantity.

Along with Gerber file format they accept files from most PCB CAD software like Altium, Eagle, Orcad, Protel. Within days they send back images of processed PCB layers for confirmation and correction (if needed) and within week manufacture PCBs.
And yes, they sell parts too ;-)

Sunday, September 19, 2010

DIY laser spirograph (part 6)

Improved SMT version of PIC18F1320 based controller for laser spirograph.

Controller board is completely redesigned and tightly populated with SMT components.

MIC4680 based switching voltage regulator eliminates needs for bulky aluminum heatsink.
As result controller has significantly shrunk in size and now it can be used as a base for true pocket laser show projector. 
Controller's retained embedded voltage regulator to supply power for low power laser module within 2 - 4V. Regulator's built around SMT LM1117 chip and incorporates dedicated open area of PCB as a heatsink.
Controller supports 5V and 12V fans. Fan voltage is set by wire jumpers on board.

Controller v2 for laser spirograph. Final design.

Along with auto and manual modes of operation modified controller's acquired new exciting feature.
It's ability to store your favorite patterns in internal memory with just press of a button and replay them as a slide show.
Up to 80 patterns can be stored and replayed as endless sequence. Time of displaying single pattern is adjustable and can vary from 3 to 60 seconds. Also there's manual step mode when next pattern in sequence is triggered by a button.

Monday, September 6, 2010

DIY laser spirograph (part 5)

Final steps. Enclosure.

Voltage regulators require individual heatsinks!!!. Metal tab of LM7805 is connected to ground but in LM317 metal tab is connected to output terminal therefore common heatsink for both regulators is strictly unacceptable.

Heatsinks can be easily fabricated from available light gauge metal.
Couple custom shaped  pieces of scrap aluminum will do the trick.
Use of thermal compound is preferable.

Friday, September 3, 2010

DIY laser spirograph (part 4)

How to build spirograph controller from a kit. Step by step assembling guide.

NOTE!!! Given information is provided for visual reference and may not reflect latest design changes and modification but every ordered kit supplied with updated schematic and component map. 

Kit includes PCB, preprogrammed with latest firmware microcontroller PIC18F1320 and all electronic components to build controller for advanced laser spirograph.

Complete part list:
1 x Capacitor 100nF          
1 x Pol Capacitor 100uF      
2 x Pol Capacitor 10uF          
1 x Diode 1N4148           
3 x 2N7000 MOSFET           
2 x Resistor 10K          
4 x Resistor 330R            
3 x Potentiometer 10K          
1 x Resistor 10R          
1 x Resistor 240R          
1 x Potentiometer 1K          
1 x SPDT Toggle Switch       
1 x preprogrammed microcontroller PIC18F1320    
1 x MC78M05ACT Voltage Regulator   
1 x LM317BT Adj Voltage Regulator   
1 x DIP-18 socket           
1 x ICSP Header, 5-Pin       
1 x PCB                

As electronic device, controller is pretty simple and assembling requires only basic soldering skills and minimum set of tools:

 - multimeter;
 - soldering iron, liquid flux, wire solder;
 - fumes extractor (or work in well ventilated area);
 - tweezers, pliers, wire cutter, small flat screwdriver;
 - 22 AWG stranded wire;
 - alcohol, soft brush;
 - heat shrink tubing;
 - glue gun.