If you have a project that needs a bit more than 3.3, 5 or 12 volts have a look at this Home Made 250 kV High Voltage DC Power Supply! Of course this isn’t your typical supply for the Arduino project sitting on the corner of your bench. One thing to note is that this supply can pack a deadly punch so be very careful if you intend to do some tinkering on your own.

“The Cockroft-Walton multiplier uses a cascaded series of diodes and capacitors to generate a high voltage DC potential from an AC input through a circuit topology that uses diodes to charge capacitors in parallel and discharge them in series.  The output polarity of the Cockroft-Walton multiplier depends on the way in which its diodes are oriented, so the output polarity (referenced to ground) of a high-voltage DC power supply is usually set during the design.”

If you have a jailbroken Apple iPhone you might want to start using your phone to control your car. Check out this iPhone SMS Remote Car Starter project by Will O’Brien from Biobug that goes through the details and has the code available if this is something you want to play with.

Via: Apple Phone Hacks and Electronic Labs

“Requirements:

An old jailbroken iPhone, an Arduino, iphone breakout board (I used a PodBreakout Mini) 4x 10k resistors, 1x TIP120, a 5 volt switching supply cell charger (easier than building one), some wiring ability and a general understanding of unix/perl/arduino. (See the packages on my dev phone in this post.”

This RGB based LED ring is the second version of a project which has three LED driver chips which enhance the brightness of the color lights. I found the second version more appealing than its ancestor when I watched the video. The first version used only one LED driver IC which was less attractive than this one. If you want to give this cool RGB based LED ring a try then you can refer with the whole procedure described below by Robert here.

“As of ’2.0 beta’ (likely to become the final version) it comes with 3 dedicated constant current LED driver chips (MBI5168), which completely avoids multiplexing the LEDs and boosts brightness again. Color balancing is done entirely in hardware using 3 potentiometers. The hardware differences should be taken care of in the core part of the demo code, ‘User-land’ code is mostly the same”.

Windell H. Oskay from EMSL created a detailed discussion on using Zener Diodes. He has designed a circuit flow using Zener diodes to control the reverse breakdown while designing up a circuit which is impossible to do if he would had used a regular diode.

“Zener diodes are a special type of semiconductor diode– devices that allow current to flow in one direction only –that also allow current to flow in the opposite direction, but only when exposed to enough voltage. And while that sounds a bit esoteric, they’re actually among the handiest components ever to cross an engineer’s bench, providing great solutions to a number of common needs in circuit design. “

Our friend Pete Mills developed this great ATTiny based Electronic Candle, we have seen electronic candles before but what makes this one shine is how the flickering was done. Pete actually sampled the actual flicker patterns of a real candle flame so that this reproduced flame would look as close to the real thing as possible.

You can see some other electronic candle designs here for inspiration.

“The ATTiny Candle is an LED candle. It uses a high brightness LED and some software to mimic the look of a traditional candle without the dangers associated with an open flame.

I figured the hardest part of this project would be making the flicker look realistic, so I decided to let nature do that part for me.  I made this candle with a Light Detecting Resistor ( LDR ) and a fixed resistor acting as a voltage divider.  This is fed to one of the ATTiny85′s ADC inputs and sampled at discrete time intervals.  At this time, the sample rate is 100mS.  These 8-bit light level values are then stored to EEPROM so that the candle can recall the flicker pattern to play back on the LED that is connected to a PWM channel after being turned off.  You only need to program the pattern once, but you can program it over and over again with just the push of a button.”

Todd Harrison from ToddFun has experimented fixing a timer control which he was using to turn on and off the Christmas lights after a certain span of time. With a soldering iron and a bit of troubleshooting we learn what the problem is. Turns out that a part is needed to permanently repair the unit but when Todd has the new part the fix should only take another 5 minutes. If you are facing the same problem then you can follow his procedure that he has documented in the video.  

“I have an exterior timer control that turns my Christmas lights on at dusk and off after 6 hours. I noticed they never turned off one day and thought I had left the timer control set to the ON position. But no, it was set to off 6 hours after dusk. I then set the selection switch to OFF but still it was on. I unplugged and plugged it back in but got the same problem. It was time to go to the electronics bench”.

Checkout this cell Jammer or we can say Dirty transmitter. A Dirty transmitter transmits junk within the cellular phone bands. This model is good enough to knock out pesky cell phones for about 10 to 15 feet, just perfect for a quite cup of coffee in your favorite coffee shop.

Via : EEweb

“The 555 timer [8 pin] IC simply makes a noise. It’s coupled via C4 [electrolytic] to modulate the MRF transistor oscillator. With C1 set at roughly 1/3rd, you will be close to 900 MHz. By sweeping the C1 trimmer capacitor, you can swing the output frequency from 800 MHz to 2 GHz with the transistor and values shown.”

Thanks to Mike for sending in his German Word Clock. He has used some SPI controlled RGB lighting strips to make wiring and controlling the lights simpler. So that the letters look good he has built and installed an MDF baffle with 100 light holes in it. 

 ”To control the clock, an ATmega8535 is used. This is a real-time clock (DS1307), a Bluetooth module and a Darlington array to control the 4 leds around the clock, each of which represents the minutes (Example: The Time Clock “It’s five after two” and two LEDs lights -> Thus, it is seven to two).

- 40 × 40 cm, so that you can read the clock at a distance greater good

- Mirrored glass front panel or Plexyglas

- “Wooden Shield” of the light cone to prevent unwanted light from letters

- To clean aluminum frame around edges have

- RGB lighting

- Brightness sensor

- Control by smartphone”

You have probably heard about the capacitor problems that have plagued the motherboard and computer power supply manufactures. Well other mass produced electronics are not immune to this issue. Viktor was given an LCD monitor once it was determined to be non-reparable by a local repair shop. These days local electronic repair shops are basically board swappers, their flowchart will point to a defective board in the system and if it is worth replacing it that is the fix. Only problem is that the board for a piece of electronics that is 2 or 3 years old will probably be more expensive that a modern and probably better new replacement. Not to mention that the repair shop will probably want a hundred bucks for bolting in the new board.

After a visual inspection of the circuit board inside the monitor it was quite obvious that one of the capacitors was defective, you can see it in the picture (the one with the bulge). After replacing this capacitor the monitor magically came back to life. I wonder if the repair shop employees knew to look for this, even if they sis do they have a soldering iron on hand would be the next question…

 Check out the spingarage blog for some details on the FroBoard, this board packs a ton of features onto the single compact board. If you are interested in making one for yourself all of the board details are available here.

“The FroBoard includes all of the hardware necessary to drive the power section of a brushless motor controller. A functional controller can be built with nothing more than a FroBoard, 6 MOSFETs or IGBTs, and a little ingenuity. Here’s what’s on the board:

• A PIC18F4431 processor, clocked at 20 MHz. Check out the datasheet, it’s a beast.
• 3 FAN7390 half-bridge drivers, capable of driving everything from IRF510s all the way up to big IGBT modules. All wired up to the power-control PWM module in the PIC. They’re also fully isolated through optocouplers and isolated power supplies, so they’re suitable for high voltage systems requiring isolation.
• 6 logic level PWM outputs, configurable as complementary PWMs, for driving small transistor power sections or for debugging with an oscilloscope.
• A MAX232 chip wired up to the EUSART of the PIC for easy interfacing to pretty much anything (a computer, for instance) through the on-board DB-9 connector.
• 18 programmable I/Os (including 9 which are configurable as analog inputs) wired up to 3-pin headers for easy access.
• Two relays hooked up to the PIC. We use ‘em to control big contactors (through a secondary, larger relay) in EV drive systems.
• Two debugging LEDs wired up to the PIC. They’re blue, which is awesome.
• A standard 6-pin programming interface for programming with any standard PIC programmer.
• A voltage regulator to allow use with 9-18V DC power supplies.”