DIY switch indicator light

Customized light indicator for wall switches.

Holes were made with a piece of tungsten carbide drill with engraving tool. After milling holes were filled with clear glue. LEDs are covered with pieces of opal diffusor and a piece of white thick paper (120 g/m2) for additional light scattering.

Switches control low-voltage signal, no mains voltage is applied. LED's are driven independently by light control unit.

Image Editor/Converter for embedded (MCU-based) projects

Hi! Some time ago I've bought Arduino Due board (based on Atmel SAM3X8E chip) and 4.3'' 16-bit color TFT display. When I started to code graphics output, I've found that existing picture tools not very handy for me. So I've made a helper tool for graphic conversion. After some time, I've decided to make this program open source and add some useful functions.

I've tried to make easy-to-use image editor/converter, and hope I succeeded.

PixelImage

works under Windows (Linux users, sorry...)

at SourceForge.net

If you find this project interesting, please feel free to leave comments and bugreports at sourceforge.

Analog audio via UTP twisted pair

Hi all! Every time I want to listen music from my collection in another room (ex. kitchen), I have to take my tablet, connect it to audio system and setup streaming over WiFi. It's boring.

But what about direct audio from sound card to another room without network transcoding? I know there are devices starting from low costs to high-cost multiroom systems. Not my choice. It is interesting for me to make some kind of "multiroom audio" by myself =)

Buck-Boost LED Driver (34063)

Hi all! Earlier this year I've made improved version of 34063 LED driver. This is combined buck-boost converter witout output voltage inversion. Now I have some time to describe it =)

Font Editor for embedded projects

Hi! I've started a new project: Pixel font editor for DIY embedded projects.

Features:

• Character map generator from any installed font with flexible options.
• Individual character editor
• A bunch of code export options:
• UTFT library support
• Array for Nokia 3310/1202 LCD's
• Customized array (byte,bit order, packed character data)

Take a look here:

at SourceForge.net

9V multimeter powered from single AA battery

Hi! Another 9V battery was dead in my 830 multimeter. I've used this situation to make some modifications. I have a lot of half empty AA and AAA batteries, so I decided to power up multimeter from 1.1V (fresh AA/AAA have 1.5V).

DIY solder smoke absorber

Hi! As you could note my hobby is electronics =) So solder station is my frequently used tool. Long time I've used it without smoke absorber. I think that it is really useful thing =) I had a choice: buy it or make it. Of course, the simplest way is to buy, but I'm not looking for simple ways).
So I've decided to make something like this:

Update: Device is complete =)

AM2320 library for AVR's without hardware TWI support

Hi! Some time ago I've bought several AM2320 sensors. They have I2C interface, so it is very easy to use them with AVR's that have h\w TWI support. But what about low-end MCU's without full TWI implementation (Tiny2313, Tiny24, etc.)?
First I tried to use USI module for TWI implementation. As for me resulting code was too "fat" for 2Kb FLASH and there was no need for full TWI feature support (the only TWI device in my project was AM2320).

After some time spent on datasheet reading and hardware testing I've wrote a C library for these sensors. Please note that AM2320_ReadData function writes raw data to variables. This notice is actual for negative temperature values, where 0x8000 bit is set.

AM2320 Datasheet

Driving MOSFET's in a cheap way

Hi all!
As you know MOSFET-s are definitely best choice for switching-mode applications. But in most cases they need a gate driver circuit to work properly (of course, if you don't want o make a heater =)). There are lots of driver IC's, but I decided to go another way and test simple discrete driver.

Few days ago I bought some BJT's: SS8050 and SS8550. they are fast (~150-200 MHz), have high collector current (0.7A continuous, 1.5A pulse). Vce is about 20V (most FET's Vgs value).

So I've made two drivers on a breadboard: N-FET low-side and N-FET high-side with bootstrap.

To drive MOSFET(Q1) 8050 and 8550 BJT's are connected as totem-pole emitter follower. I've tested these drivers with 5V signal source, so I've added an inverting level shifter (Q6, R26). If TL494 (for example) is used as control source there is no need in level shift in most case.

Load was 12V 21W auto lamp (~1.8A). MOSFET was without any heatsink. Control signal: square wave generator with PWM on TL7555 timer with output buffer (74HC04). Frequency: 2KHz to 70 KHz.

Light for Dremel Workstation 220. New version.

Hi!
About two years ago I've made a work area lighting for my Dremel Workstation 220. Really simple  - 3AA batteries, resistor and a bunch of white LEDs (all in parallel) from broken flashlight. Not bad, but these LEDs have narrow light spots and large power consumption.