[Nick] wrote in to tell us about his first blog post. He’s showing off a PWM LED driver he build around a 555 timer. This project uses a lot of basics; some 555 experience, PCB etching, and surface mount soldering. We’d like to know more about the blue substrate on his circuit board!
After seeing the BOM spreadsheet with KiCAD integration a couple of weeks back, [Vassilis] sent in a link to his own Excel-based Bill of Materials helper. We’re wondering if anyone has a similar tool that will work with Open Office?
While we’re on the topic of downloadable documents, here’s a reference PDF for all types of DC measurements. The collection is a free offering from Keithley. [Thanks Buddy]
Since you’re brushing up on your knowledge you may also be interested in a free online microcontroller course offered by UT Austin. They’re targeting the Tiva C Launchpad as the dev board for the class.
This website seems to be a little creepy, but the teardrop shaped 3D printed music box which is being shown off is actually rather neat.
Hackaday Alum [Phil Burgess] threw together a point and shoot camera for Adafruit. It’s a Raspberry Pi, camera board, touchscreen display, and USB battery all rubber banded together. The processing power of the RPi is used to add image processing effects which are shown off in the demo video.
We don’t own a DeLorean. If we did, we’d probably follow the lead of Queen’s University Belfast and turn it into and electric vehicle. [Thanks Jake]
The 3D photocopiers are coming. Here’s a hacked together proof-of-concept from [Marcelo Ruiz]. After laser scanning the part is milled from floral foam.
I spent quite some time trying to find a way to get OpenOffice to make arbitrary HTTP connections and ended up having to do a system() call (or whatever they call it) from “BASIC” and write a script that would do the query for me and then compact it into something I could insert into a cell. Then some more scripting let me parse the cell contents and extract various quantity numbers etc.
I need to resurrect the spreadsheet in the next few days because I need to do another round of PCB assembly, but it’s going to be complicated by the fact that Digikey seems to be constantly be changing their system in order to frustrate the ability to scrape data off of it. You’d think they’d *want* people to automatically utilize their database as a means of being the more likely supplier, but apparently not.
Digikey didn’t add “sort by price” until years after the greasemonkey scripts’ widespread prevalence. I have to assume they got a noticeable amount of profit from making it hard for people to find the cheapest item.
Sometimes you don’t want the cheapest item. For example: everytime i use LEDs as a Graetz rectifier the cheap ones always burn out, more expensive ones are fine.
In my case I select the exact part I want as part of my BOM, the spreadsheet’s job is to keep track of them all, store how many I have on hand, and give me some smart tools for finding the number of each part I need to order. I can also disable my stock count and crank the build quantity into production levels to find out how much the BOM total is for 1000’s of units or whatever, vs the smaller prototype quantities. I’ve started to work on it and will try to make some kind of distributable package soon, at least for my environment (libreoffice on Linux).
IMHO selecting components is always: sort-by-price and check the cheapest item. Sometimes you find it doesn’t fit in your application. Then either you change the search criteria or you manually try the next one.
I tend to sort by availability first, it doesn’t matter how much things cost if you can’t get them.
If you are prototyping, you should probably shoot for the more expensive, more fully functional versions of parts. It will save you time, if your design changes and you can keep using the parts you’ve already chosen. Most electronic parts are really cheap anyway.
The blue stuff in [Nick]’s PCB etching is Press-n-Peel I believe.
I can assure you its not ;) I use UV exposure for my etching. I got this circuit board at my college. There is a site where we can etch for free, and that’s where I got my circuit board. I honestly don’t know where they got it, I’ve never even seen the people that keep the etching spot running or else I’d ask!
I got some copper clad board with blue substrate recently – I believe it was from rapidonline and manufactured by Bungard. It was a bit confusing as I wanted photosensitive board which comes with a blue adhesive covering. This was definitely plain copper though, I’ll dig out the details when I get home.