A while ago I needed some small value resistors as current shunts and I started wondering about the feasibility of using traces as resistors.
There are many theoretical reasons as to why copper traces make bad shunt resistors, but I found surprisingly little practical data.
The traces are (from left to right):
– 20 mil wide, 1221 mil long, should be ~30mOhms
– 6 mil wide, 611 mil long, ~50mOhms
– 12 mil wide 1221 mil long, 50 mOhms
– 6 mil wide 1221 mil long, 100 mOhms
Using traces as resistors – [Link]
Circuit board business cards have been done. But since circuit boards are, literally, my business, I felt that I needed one too. Of course it also had to be special. Research and experimentation took a long time with this one and the design even sat dormant, ready, for a while before I sent it out to fab.
An engineer’s emergency kit business card – [Link]
pinomelean @ instructables.com writes:
There are many ways to make your own homemade PCB’s, They all work, but some better than other, some faster than other, ones are cheap and others expensive….
After several attempts, i found the way of making PCB’s, wich is the cheapest, easiest and fastest for me.
I hope this instructable will help you to decide what’s the best method for you, because there are so many to choose.
PCB making guide – [Link]
Custom Circuit Boards, LLC. is a quick turnaround PCB prototype manufacturing company located in Phoenix, Arizona with 32 years of experience on the field offering the best quality printed circuit boards from PCB prototypes to production PCBs. They also have the capabilities to provide multilayer PCBs up to 24 layers. As a leading PCB manufacturer, they provide their services to the aerospace and military industry, medical and bio-medical, automotive industry, and even to hobbyists and student’s with only one thing in mind, quality assurance.
“We started Custom Circuit Boards because we were tired of the poor customer service and board quality from other PCB companies in the industry. We knew that we could do better. Now, every day we do ourbest to exceed our customer’s expectations by providing exceptional personal customer service and competitively priced high-quality printed circuit boards that are delivered on time.”
Custom Circuit Boards fabricates all of their PCBs in their USA factory and they are continually investing in better machinery and technology in order to improve their PCB capabilities. The standard prototype PCB lead-time is 10 days, however, depending on the complexity of the boards and quantity, it could be shorter. They also provide 24 hour, 2 day, 3 day, 5 day and 10-day turnaround when needed. Read the rest of this entry »
Diyouware build a low-cost PCB printer for photoresist using a blue ray module. The UV laser scan the PCB surface and sensitize the UV resistive dry film.
About a year ago my brother and I engaged on a quixotic project to build from scratch a low-cost PCB printer for photoresist.
Finally we did it using a Blue Ray optical pickup (PHR-803T) and his UV laser/electronics to sensitize Dry-film.
The optical pickup is used through his own connector without any modification. We deduced the pinout using reverse engineering and designed a driver for an Arduino UNO to control it. Basically, we can adjust the laser power, turn the laser on/off, move the focus lens servo and read the photodiode array signal.
The control of the pickup allowed us implementing a laser auto-focus algorithm based on the astigmatic method. Is the same method use it to focus the laser beam on the Blue Ray disc.
The mechanics is an X/Y Cartesian table which moves the pickup with two Nema 16 stepper motors and T2.5 timing-belts. Most of the printer framework has been printed with a 3D Reprap printer, so itʼs replicable.
We also developed the Arduino UNO firmware, based on 3D printer firmware Marlin, and the server side software which send the HPGL commands to the printer. Eagle Cadsoft complete the “tool-chain”. It supports HPGL in his CAM processor, so is easy to design the circuit with Eagle, generate the HPGL file and send it to the printer.
DiyouPCB is a prototype and it’s still not perfect: we have some resonance and vibration issues that affect the quality of printing, but it’s a first step to have an alternative method to indirect methods as the famous toner transfer.
DiyouPCB is a PCB printer which uses a Blue Ray™ pickup – [Link]
By understanding the manufacturing process you will be able design PCBs that can made more easily and cheaply. Designing boards that fit within industry standard specifications gives you two advantages: you keep down the cost of your end product, so that it will sell better; and you improve its long-term reliability, so that your customers will keep on coming back to you. And when you want to push the boundaries of technology (and who doesn’t?) you can sit down with your chosen board manufacturer and discuss your requirements knowing where he is coming from.
Eurocircuits – how to make a 4-layer PCB (full version) – [Link]
Dave tests the myth that plugging a PCB VIA with solder does nothing (or not much) to improve the current handling capability. Is manual wire feed-through any better?
EEVBlog #543 – PCB VIA Current Investigation – [Link]
DIY Goodies show us a way to make flat vias for your PCB projects. diygoodies.org.ua writes:
Catching up the development of printed circuit boards at home i often faced with the problem of “the bulbous” vias. Usually homemade double-layer boards soldering from both sides with the thin wire, the result usually satisfied but if you need to make VIA under the chip TQFP48, SOIC16 and that’s is a real problem, if contact is very bulbous it will be simply impossible cleanly solder chip as its legs will hang in the air.
DIY PCB with flat VIA’s – [Link]
cpeniche @ instructables.com writes:
This Instructable is about dry film solder mask, in other words, is the green stuff that is on top of the circuit board.
I like to use smd components in my circuits board because I don’t have a computerized drill machine and do in it by hand for a big
boards are really tedious.
Soldering smd components in a copper board without dry solder mask, especially for those little capacitors and resistor of 402 in size, becomes a tough challenge and of course those micro controllers with almost zero space between pins.
Dry Film Solder Mask – [Link]