Batteries are cheap, small and relatively safe way of having portable energy source. There are many types of batteries with different characteristics and uses. Probably many of you heard terms battery and cell referring to the same. But from technical perspective these are different things – cell is a single unit which houses a single chemical reaction and produces electricity, while battery is a pack of cells.
Batteries and cell characteristics - [Link]
Climate controller reads temperature and humidity values from SHT11 where are temperature and humidity sensors combined. Temperatures scale reaches from -40 to 123ºC or (-40 to 254ºF) while humidity readings can vary from 0 to 100%.
Controller board can control three distinct CD outputs with 10A load or 2 DC outputs and one AC up to 4A. This project can be ideal for greenhouse control, small room climate control or in other areas where temperature and humidity has to be sustained. Complete project files including C source, hex file, schematic and PCB can be downloaded here.
PIC based climate controller - [Link]
Mike writes -
Do you like the idea of tesla coils and other high-voltage sparking stuff, but don’t have the time, money or patience to build something that elaborate? Here’s a fun little project that can make big, fat, noisy sparks at least 2 inches long, and can be built very quickly and cheaply. The Marx generator consists of an array of resistors, capacitors and spark gaps arranged as follows… [via]
Make a “Quick & Dirty” Marx generator - [Link]
Ryan made this guide to different common electronics connecters. He writes:
Online vendors, particularly sites like Jameco and Digikey, tend to be targeted at engineers who already know exactly what they’re looking for. If you don’t know the right search terms, finding the right part can be a bear. Since I made my start in electronics a few years ago, Octopart has made finding parts much easier, but you still have to know what you’re looking for! In hopes of helping people who’re building their first homebrew boards know what to look for, I’ve tried to compile a bit of what I’ve picked up. [via]
Connectors Demystified - [Link]
Here’s a prank-style kit from MadLab Electronics, the IR-ritator. Schematic included -
A practical joke for playing on anybody who uses an infrared remote to control electrical equipment such as a television. The IR-ritator can jam a remote control and make it seem unreliable, and it can also record and mimic a remote control and disrupt the normal operation of a piece of equipment. [via]
The IR-ritator - [Link]
Greg’s “cameleon lamp”, he writes -
Concept: To design a light that mimics a color if shown to it. Design: lamp driver. LEDs are very efficient as they only emit one frequency of light, and because of this the light produced could be perceived as flat and lifeless. Instead i used tungsten bulbs because unlike LEDs they aren’t flat and lifeless. Because the Arduino cannot provide enough current to power a tungsten bulb without damaging the Arduino chip, I had to use transistors to turn a separate power source on to power the bulbs. This also meant that the lamp wouldn’t draw too much current from the laptop. To do this i connected the pwm pins to base of the transistors, and grounded the transistors to the Arduino’s ground in series with diodes to prevent current flowing back through the tungsten bulbs from the Arduino. Because i used the pwm pins i could dim the bulbs the same way one can dim LEDs in the Arduino code.colour sensor. Because I wanted the lamp to detect colors and mimic them, I prototyped a simple color sensor. [via]
The cameleon lamp - [Link]
This looks great! Draw your own circuits -
Apply instant traces on most surfaces (epoxy, glass, plastic, metal). Draw traces on circuit boards, repair defective traces, make jumpers and shield electronics, design prototype circuits and repair rear-window heater traces. [via]
CircuitWriter conductive ink & pen - [Link]
“Otto” which means “ear” in Greek, is a device that amplifies hidden sounds in the environment using suction cups and magnets. Used as multiple units, the project can produce a layered sonic experience through emitting ambient sounds. Pretty interesting idea for creating a musical performance of sorts, we just wonder exactly how melodic the resulting sound could be or if it would just result in a lot of white noise. [via]
Otto project amplifies hidden sounds - [Link]
Steve writes -
I am learning about electronics by building a toy laser gun. This is the sound and light effects circuitry in development. The top board has a 555 monostable timer, which turns on a bright red LED, a laser, and the sound effect. It also triggers a second board, which has 555 oscillator which is triggering a 4017 decade counter chip. That circuit is the blue LED chaser. I have it timed so that it goes one cycle during the time that the trigger from the first timer is high. Whew! a lot of work to turn on a couple of blinky lights. [via]
Homebrew laser toy blaster effects - [Link]
With this circuit you can drive a unipolar stepper motor. It operates in full step mode. You can get a stepper motor from an old 5.25 disk drive. The AVR2313 micro controller controls the pulses for the stepper motor. The pulses are amplified by the ULN2003 driver. The driver accepts 5V inputs, the output for the driver is up to 30V so you can connect an stepper motor of up to 30V. With the two push switches you can drive the stepper motor CW or CCW.
AVR Stepper Motor Driver - [Link]