[Quinn Dunki] has been busy through the holidays giving her 6502 processor-based computer a place to live. The most recent part of the project (which she calls Veronica) involved designing and etching a mainboard for the device. In the picture above it’s the vertical board which is right at home in the backplane [Quinn] also designed.
The project is really gaining momentum now. You may remember that it started off as a rather motley arrangement of what we’d guess is every breadboard she owns. From there some nifty hex switches gave [Quinn] a way to program the data bus on the device. Many would have stopped with these successes, but the continuation of the project makes the hardware robust enough to be around for a while. The single-sided boards are playing nicely together, and the next step is to redesign the ROM emulator to use chips for storage. [Quinn] alludes to a side project in which she plans to build her own EEPROM programmer to help with getting code into the experimental computer.
Article source: http://feedproxy.google.com/~r/hackaday/LgoM/~3/xRmOeADI5no/
Building your first circuit is empowering, but make sure it’s not too empowering. [Jon] sent in a great tutorial of power protection circuits to make sure you don’t release the mystical blue smoke that make electronics work.
There’s an in-depth tutorial of the classic series diode that’s the simplest of all power protection circuits. There’s not much to it – just a diode that provides reverse polarity protection. A fuse and parallel diode doesn’t have the voltage drop a series diode has, but doesn’t do anything for an overvoltage. A P-channel MOSFET gets around the problem of voltage drop, and [Jon] gives us some really nice empirical data to demonstrate his testing setup.
There’s a ton of nice write ups on [Jon]‘s site that are perfect for getting ideas for projects like ten switches on one pin and some strange stuff [Jon] picked up at his Goodwill. If you’ve got any tutorials on general electronics, be sure to send them in on our tip line.
Article source: http://feedproxy.google.com/~r/hackaday/LgoM/~3/YSxELXkaN-4/
Article source: http://www.instructables.com/answers/Batterysand-charging-methods-for-12V7Ah-Pbhow-m/
We love the extra touches that [Andrianakis Haris] added to his two-zone electronic thermometer. It includes features that you just wouldn’t find on a mass-market commercial product because of issues like added cost. For example, you can see that the PCB juts up above the LCD display, allowing the module to be mounted on a pair of screws thanks to the keyhole shape that was drilled in the substrate. I increases the board size greatly, but on a small hobby run this won’t usually affect the price of the board depending on the fab house pricing model.
The design uses an ATmega8 microcontroller to monitor sensors in two different places. There is an onboard LM35 temperature sensor for monitoring the space where the unit resides. A remote sensor module uses a DHT-11 chip to gather data about temperature and humidity. That sensor is wired, but there is one wireless option for the device. Data can be pulled down from it via an optional Bluetooth module which can be soldered to a footprint on the back of the board.
Check out the video after the break to see temperature readings pulled down wirelessly.
Article source: http://feedproxy.google.com/~r/hackaday/LgoM/~3/LLI7g8mWquI/
[Giorgos Lazaridis] needed an AC adaptor for his Canon PowerShot camera. He hit eBay and was excited to find this branded adaptor for just five bucks! It works and, even though it would sometimes reboot his camera if the cord was twisted around in the jack, he was satisfied that it did what it was supposed to.
That is, until one day he observed some very peculiar behavior while taking pictures of a PIC circuit he was prototyping. When holding the camera and putting his other hand near the breadboard one of the status LEDs in his circuit began flashing sporadically. If he was using the camera with batteries instead of the adapter this didn’t happen.
His first instinct was to hook up the adapter to his oscilloscope and see what is happening on the power bus. The signal is incredibly noisy. Shockingly so. [Giorgos] cracked open the case to see what is going on with the power supply circuit inside. You simply must view the video after the break to see the horror-show he found. The board is poorly soldered, components are not properly seated in their footprints, and our favorite is when [Giorgos] points out a squiggly trace which takes the place of the smoothing inductors.
Have you documented your own fake electronic hardware finds? We’d love to hear about them.
Article source: http://feedproxy.google.com/~r/hackaday/LgoM/~3/Ch-LZxixQio/