This is the second in my 3-part vlog mini-series on high quality PCB manufacturing. In these vlogs I will show the specialized tools and equipment that you will need to make your own high quality PCB’s from scratch, with step by step demonstrations of each stage – from rendering and checking the artwork, to applying the resist to copper clap boards, to etching, to drilling the PCB’s, to component placement and soldering, and finally to defluxing and finishing.
The PCB artwork and schematics for the Apollo Launch Vehicle Digital Computer Logic Devices are available on my Design and Engineering page.
Boost converters (or step-up converters) are in a class of circuits called DC-DC conversion circuits. These can operate more efficiently than linear regulators like the 7805, and unlike linears they can be designed to have a higher output voltage than their input voltage – potentially useful for low-voltage sources like some steppers.
Here’s the first of a three-part weekly series from Fran showing her process for manufacturing PCBs, from Fran’s Writings on Design and Engineering. Check back next week for the next episode!
This is my 3-part vlog mini-series on high quality PCB manufacturing, and introduction to my “make your own LVDC logic devices” project. In these vlogs I will show the specialized tools and equipment that you will need to make your own high quality PCB’s from scratch with my own refined methods, with step by step demonstrations of each stage – from rendering and checking the artwork, to applying the resist to copper clap boards, to etching, to drilling the PCB’s, to component placement and soldering, and finally to defluxing and finishing.
A new great testing shield component from MobileWill to complement William’s USB Tester:
Today we have started the fundraiser for the USB Tester OLED backpack with the display. This is a great addition to the USB Tester, which makes it easy to monitor voltage and current for any USB device. Now you don’t even need your DMM. You can use this to see how much power your Raspberry Pi is using or that custom Arduino based project you are working on. This is a great way to make sure you aren’t getting a voltage drop due to that USB hub you are using. Check out the product description below and thanks for your support. You can back the project here….
Sebastian created Widerstand ist Zwecklos, an ohmmeter lamp that displays resistor color codes. He writes:
“Widerstand ist zwecklos” is german for “resistance is futile”, but also “resistor is useless”, which is absolutely the point in this project. i teamed up with my dear friend jan and we created a device that measures resistance and displays it as a resistor color code. an optional cheat mode also displays the resistance as a decimal number. needless to say it is shaped like a giant resistor.
Another great video from my friend Alan Wolke, this time about op-amp power supply considerations. He explains the differences when using op-amps on a single supply, a split (or bipolar) supply, and with a virtual ground. He writes:
This video discusses the power supply considerations for op amps. It talks about split or dual power supply and single supply operation, and why the op amp often doesn’t care which you use! It shows how traditional op amps designed for split supply operation can be used in single supply applications. The most important consideration generally is taking care of where the input and output voltages are with respect to the supply rails. The input voltage and output voltage range specifications are examined in a datasheet. The operation of a op amp in a single supply application is examined on an oscilloscope. This operation is compared to a modern rail-to-rail op amp in the same circuit.
This answers a lot of questions which beginners have when first learning about opamps, and explains the reasons behind some opamp specs in an exceptionally clear manner. Check it out!
Here is the schematic diagram for the original arcade version of Pong, the first digital video game. Unlike other video games of the time, Pong used an all digital circuit to produce the graphics, sound and game control. There is no software or processor, just a collection of 66 discrete chips performing a single function, inter-connected to create the game we know.
For the home version, a single specialized chip was used to replicate all of the functions of the arcade version.
The different sections have been colour coded. As you can see many of the part annotations are very hard to read and copying artifacts obscure many details.
Great tip for doing more with your dumpster-dive electronic plunder — a tool to help you learn more information about the components you discover. From Hack A Day.
So you just pulled a fancy component off of a board from some broken electronics and you want to use it in your own project. What if the data sheet you found for it doesn’t include measurements for the footprint? Sure, you could pull out your digital calipers, but look at the measurements in the image above. How the heck are you supposed to accurately measure that? [Steve] found an easy answer for this problem. He uses microscope software to process an image of the board.
One common task when working with a microscope is measuring the items which are being viewed under magnification. [Steve] harnessed the power of a piece of free software called MiCam. One of its features is the ability to select an area of the photograph so serve as the measuring stick. To get the labels seen in the image above he selected the left and right edges of the board as the legend. He used his digital calipers to get a precise measurement of this area, then let the software automatically calculate the rest of the distances which he selected with his cursor.
MiCam is written for Windows machines. If you know of Linux or OSX alternatives please let us know in the comments.
Ready to take a look at the past, present, and future of embedded technology, microcomputer programming, and electrical engineering? CC25 is now available.
We achieved three main goals by putting together this issue. One, we properly documented the history of Circuit Cellar from its launch in 1988 as a bi-monthly magazine
about microcomputer applications to the present day. Two, we gathered immediately applicable tips and tricks from professional engineers about designing, programming, and completing electronics projects. Three, we recorded the thoughts of innovative engineers, academics, and industry leaders on the future of embedded technologies ranging from
rapid prototyping platforms to 8-bit chips to FPGAs.
The issue’s content is gathered in three main sections. Each section comprises essays, project information, and interviews. In the Past section, we feature essays on the early days of Circuit Cellar, the thoughts of long-time readers about their first MCU-based projects, and more. For instance, Circuit Cellar‘s founder Steve Ciarcia writes about his early projects and the magazine’s launch in 1988. Long-time editor/contributor Dave Tweed documents some of his favorite projects from the past 25 years.
The Present section features advice from working hardware and software engineers. Examples include a review of embedded security risks and design tips for ensuring system reliability. We also include short interviews with professionals about their preferred microcontrollers, current projects, and engineering-related interests.
The Future section features essays by innovators such as Adafruit Industries founder Limor Fried, ARM engineer Simon Ford, and University of Utah professor John Regehr on topics such as the future of DIY engineering, rapid prototyping, and small-RAM devices.
Everything you need to know about how Thermocouples work.
K type thermocouples, the Seebeck effect, the Seebeck coefficient, and cold junction compensation.
Along with some practical measurements with a multimeter to demonstrate the effect.
Here’s Ken Olsen’s write up of the project he shared on last week’s Show-and-Tell. From The Maker’s Box:
My latest project was designing and building a circuit board on the web-based Circuits.io. They have made it super easy to make a PCB in comparison to using Eagle Cad and sending files to a boardhouse.
One of the first things I did with my Raspberry Pi when I got it was an Adafruit Learning tutorial on analog inputs. The Pi doesn’t have analog like the
Arduino, so it needs a little help. Using a MCP3008 on a SPI bus can get
you 8 channels of 10-bit analog. Take that Arduino! At the time, I
used Adafruit’s cobbler board which makes breadboarding things a snap.
This looked like a perfect project for trying out Circuits.io, and it was….
If you ever connected to the Internet before the 2000s, you probably remember that it made a peculiar sound. But despite becoming so familiar, it remained a mystery for most of us. What do these sounds mean?
As many already know, what you’re hearing is often called a handshake, the start of a telephone conversation between two modems. The modems are trying to find a common language and determine the weaknesses of the telephone channel originally meant for human speech.
…
The first thing we hear in this example is a dial tone, the same tone you would hear when picking up your landline phone. The modem now knows it’s connected to a phone line and can dial a number. The number is signaled to the network using Dual-Tone Multi-Frequency signaling, or DTMF, the same sounds a telephone makes when dialing a number.
The remote modem answers with a distinct tone that our calling modem can recognize. They then exchange short bursts of binary data to assess what kind of protocol is appropriate. This is called a V.8 bis transaction.
Today we went on one of the most interesting tours of this trip. It’s something that I’ve always been interested in but didn’t really know how to approach. The tour was of a chip-on-board bare die bonding assembly house. For those that don’t know, one interesting technique used for very low cost, high volume products is bare die bonding. In this process, the bare die is used rather than a die packaged in a lead frame and epoxy resin. This has two benefits. The first is that the form factor is decreased since only the bare die is used. The second benefit is that its possible to save cost since packaging materials usually add cost to a chip.
There are headaches with doing a bare die process. You’ll have to negotiate with a vendor to purchase bare die rather than packaged die and you’ll also usually have a rather high minimum order quantity. The minimum order quantity can vary depending on whether the manufacturer is set up to do bare die sales, but the general rule of thumb I’ve heard is that the MOQ would be one wafer, which for something like a simple ARM or AVR microcontroller would be in the thousands.
In terms of form factor, bare die is an excellent method to cut down on size, especially if the manufacturer only offers large packages like QFPs or even through hole packages. Actually, the main reason we went to this assembly house is because earlier in the trip, Jie was explaining her project to Bunnie and mentioned that she wanted to figure out ways to decrease size and attach chips to paper for papercraft designs. At the assembly house, I was looking closely at the bare die and comparing the form factor to a packaged die. I had always thought bare die would shrink things by at least half or more. After seeing it live, I could see that although the die was smaller, the bonding pads on the PCB also require room. If you count for the bare die and the PCB bonding pads, the size is comparable to a QFN. Hence if a chip is available in a QFN package, it’s possible to assume that there might not be much size savings by going bare die. Of course this needs to be taken with a grain of salt, since some chips are put into much larger packages than the actual die, especially if a lot of pins are needed.
It was really great to see this whole process in real life though. It started out by going up to the room that does the bare die attach. The interesting thing is that since everything is done on such a small scale, all of the equipment fits into a small room. It starts with an operator hand placing bare die on to a panelized PCB substrate with a bit of glue. The finished panels are handed off to another operator that readies it for the bonding wire attach machine. The bonding wire attachment is fully automated. After the attachment, the panels are checked and another operator will repair any errors made by the machine. The amazing thing is that the repairs are done by hand using a pair of tweezers. Amazing! Imagine manipulating thread about half the thickness of human hair and trying to insert it into a single pore. After the bonding wire attachment process is finished, the die gets a blob of epoxy resin stenciled on to it which provides mechanical strength and protects the device and fragile bonding wires.
Printable catalog (PDF)
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