[Alex Busman]’s first foray in iOS programming looks like a pretty useful tool. He came up with Ohm Sense, an iPhone app that will take a picture of a resistor and calculate the value based on the color bands. It’s a great tool that we wish we had when we were starting out. At 99 cents, the app is also much cheaper than the emotional cost of our relationship with Violet.
Continue reading “Ohm Sense Makes Sense Of Resistor Color Bands”
[Patenomics] has had some trouble finding a suitable place to work on projects in his tiny apartment. Lately he’s taken to using the stove top as a soldering platform and was looking for ways to protect the stove while adding functionality. He built this soldering platform from a couple chunks of pegboard and some hardware store parts. He’s in for under $15 and has a really functional platform that may be worth adding to your solder station.
The two pegboard pieces are held in place by threaded rod and some nuts. This hardware also lends itself to adjustable feet so that you can make the platform level and stable. The holes in the top and bottom sheets line up to receive and securely position some additional tools. Here you can see that bendable copper pipe keeps some alligator clips right where they’re needed, but future plans include adding lights, clamps, and lasers.
This makes a nice work platform to go along with your other portable electronic bench tools. But if you’ve really got the itch, you’ll eventually outgrow all of this and then it might be time to find yourself a hackerspace to join.
We all know that Eagle has its share of shortcomings. Instructables user [westfw] was particularly annoyed by the fact that while Eagle keeps copies of up to 10 revisions of your board, it cannot open those files without resorting to manually renaming each one. Even more frustrating to him is the fact that you can’t use Eagle to view two files simultaneously in order to compare layouts. This made hunting down changes quite tedious, so he started looking for a better way to do things.
While using his favorite open-source gerber viewer gerbv, he noticed that the application let him load multiple copies of the same layer, XORing the PCBs’ colors together. Realizing that with some clever color selection, he could use gerbv to automatically highlight layout differences, he set off to automate the process.
The resulting script works on any flavor of *nix, and should play nice in Windows under cygwin as well. The script reads through Eagle backup files, renaming them and tweaking the colors so that when XORed, they show up as bright red areas in gerbv. It’s a simple yet handy tool to have on hand if you happen to do a lot of PCB design.
I always have! I don’t know why, but I like the idea of using an oscilloscope screen as a general use video display. Why not? In my case it sits on my desk full time, has a large screen area, can do multiple modes of display, and is very easy control.
Making an oscilloscope screen do your bidding is an old trick. There are numerous examples out there. Its not a finished project yet, so be nice. It is actually rather crude, using a couple parts I had on hand just on a whim. The code is a nice mixture of ArduincoreGCCish (I am sorry, still learning), and includes the following demos:
The software runs on an Attiny84 micro controller clocked at 16Mhz, paired up with a Microchip MCP42100 dual 100k 8 bit digital potentiometer though the Attiny’s USI (Universal Serial Interface) pins. This is a fast, stable and accurate arrangement, but it requires sending 16 bits every time you want to change the value of one of the potentiometers so its also very piggy. I was just out to have some fun and did not have a proper 8 bit DAC. This was the closest thing outside of building one.
Join us after the break for pictures a (very) brief video and more.
If you are in the market for a PIC microcontroller programmer, you may want to consider a model with an In-Circuit Debugger (ICD). [Rajendra] put together a great tutorial on using an ICD when debugging PIC firmware, which makes a pretty convincing argument for owning one.
In his tutorial, he happens to be using a MikroElektronika PICflash2, but he says that there are plenty of other ICDs out there if you are not keen on this particular model. The PICflash2 not only acts as an ICD, but as the name suggests it works as an ICSP as well.
[Rajendra] walks us through a short debugging session using some simple code that reads data from an LM34DZ temperature sensor, displaying the results on an LCD screen. While he isn’t actually hunting for bugs, he does show how easy it is to step through the PIC’s code one statement at a time, evaluating variables and registers along the way.
[Rajendra] does point out that using an ICD does occupy a few I/O pins while running, limiting your resources just a bit. We think that being able to debug code as it runs is pretty reasonable tradeoff if you don’t necessarily need each and every pin available for use.
[Florin] picked up a cheap multimeter in order to make multiple measurements at one time. Unfortunately, he wasn’t very good at remembering to turn it off when he was finished so he burned through some batteries. Why an auto-off feature wasn’t the first thing coded into the firmware we’ll never know, but [Florin] developed his own hardware-based auto-off circuit.
It sounds like he had all of the components necessary for this on hand already. He grabbed an AVR ATtiny25 in a surface mount package. To keep the board small, he didn’t include an ISP header, but instead made long pads that could have wires soldered to them for flashing the firmware. The microcontroller drives an NPN transistor that can cut off the ground path between the multimeter and its battery. A tactile switch is connected to one of the external interrupt pins and, when pressed, gives you 15 minutes of time to use the meter. After that, the chip kills the power and goes into sleep mode. Simple, and small enough to fit inside the case.
[via Dangerous Prototypes]
When looking for things to write about, there is nothing we like to see more than well-documented schematics and code available for download. In the case of schematics, we realize that they can be a bit of a pain to publish. Many times we see them in the form of blurry JPEGs or humungous PDF files, neither of which are incredibly convenient to use. The folks over at CircuitBee thought the same thing, and have been working diligently to make it easier for everyone to share their awesome ideas with the world.
Their free service requires registration, and not much else. Once you’re in, you are free to upload your Eagle or KiCAD circuit diagrams, which are then run through CircuitBee’s servers. They convert your drawings into embeddable objects which allow others to view your project without a lot of fuss. Their embeddable schematic window can be rendered in full screen mode, and gives users the ability to zoom in on any portion of the drawing to see the circuit’s finer details.
[Ben Delarre] from CircuitBee says that the product is in the alpha stages right now, so there are plenty of features and useful tools coming in the near future. If you like to build and share, it’s definitely something worth checking out!
[via Make]
[Thanks, Sanchoooo]
