This device is a countdown timer specially designed for PCB exposure box.You can set how many minutes will be on UV light device , store this time in PIC’s EEPROM . Pressing start button lights are on until preset time ends. When lights are off an audible signal is heard. Microcontroller used is Microchip’s PIC 16F877. I used Mikroelektronika Mikropascal compiler to program the chip. Delay time 1-255 minutes.
Count down timer for UV PCB exposure boxes - [Link]
When designing PCBs that will be produced professionally (or even if you etch yourself) it is sometimes hard to get a good view of what they will look like. Most CAD programs view the design in a way that is useful during design but that is not what they will look like in the end. Some provide a view mode or 3D rendering option to get a good idea, but at least CadSoft Eagle does not. What if you want to view what your design will look like or if you just want a fancy graphic to show off your wonderful PCB? Photoshop comes to the rescue.
Using Photoshop to create a realistic PCB image - [Link]
Derek Wolfe writes:
There are a lot of hobbyists that want to design and build their own custom printed circuit boards (PCB’s). It will save you money if you’re making a lot of different board designs on a small scale. If you need to make 50 copies of something or don’t want to spend the time to make your pcb’s just order them from a professional pcb manufacturer. This procedure is for people who want to get their hands dirty and learn how to make their own circuit boards for lower cost, faster turnaround, or the simple satisfaction of it.
My method of fabricating pcb’s is based on the numerous tutorials and websites that describe the familiar ‘Toner Transfer’ process. After practicing a few years I’ve combined parts of each tutorial with some tricks I’ve learned to make this fabrication procedure. This method is useful for making single boards or panelized board designs. I prefer toner transfer vs. a photolithography based method because the copper clad boards are very inexpensive when purchased in bulk and there is no light sensitive photoresist to worry about. Photolithography is capable of better resolution and smaller feature sizes than toner transfer but it’s only a limitation for extremely small features (i.e. <0.005″ wires).
PCB Fabrication Procedure using Toner Transfer - [Link]
Over at Blondihacks, Quinn’s written up a really thorough post about etching your own PCBs, building on what she discussed in past documentation. There are a lot of tutorials out there about etching PCBs, but this is probably one of the most complete I’ve seen, particularly if you’re still getting to know Eagle.
PCB Layout and Etching Tips and Tricks - [Link]
In the last few years many inexpensive PCB services have popped up. It used to be that buying PCBs in hobby quantities was expensive and filled with gotchas.
Now, places like Seeed Studio can send your PCBs to the inexpensive prototyping factory in Shenzhen China, and ship them anywhere in the world at great prices. You get two-sided PCBs, with the works, starting at $1 per 5x5cm PCB. Turnaround is a few days, worldwide shipping starts at $3. It’s a happy day for electronics hobbyists.
Other services like DorkBotPDX and BatchPCB pool multiple orders so the group benefits from bulk pricing. Enough people are using these services that turnaround is quite fast. DorkBotPDX offers signature purple PCBs that have become quite popular.
HOW-TO: Get your PCBs manufactured - [Link]
I just finished writing up some of the details on DIY plated through holes. This is what the simple constant current source was designed for. This process was slightly adapted from Think and Tinker – a really great site for DIY PCB fab. The overall process is:
- Drill holes in the PCB
- Coat the holes with a mixture of water-proof ink and finely powdered graphite
- Cure the ink so it doesn’t rub off
- Dunk the PCB in the electroplating tank, apply current, and let chemistry do the rest of the work.
Electrochemically plated vias for homemade PCBs - [Link]
Retromaster has honed his PCB making skills to get professional quality boards at home. He’s successfully made double sided PCBs with 8 mil trace width, with 6 mil clearance. In his guide he describes how to etch the PCB with toner transfer, how to use mechanical vias, and hot to apply soldermask paint.
DIY double sided PCB with soldermask - [Link]
The PIC IC and RESET button are placed on the top side of the board. The voltage regulator, quartz crystal, and all the decoupling capacitors are on the bottom.
It was designed for the dsPIC33FJ256MC710 with digital signal controller peripherals, but it will work with most PICs in the same package. Schematic and PCB files are provided if you want to build your own.
Another Microchip TQFP 100 breakout board - [Link]