Category Archives: Electro

New projects – AllAboutCircuits.com

Hello!

I have recently started writing for AllAboutCircuits.com.

Here are my projects (I will keep updating this page)  :

DIY Arduino-Based Sous-Vide Machine

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How to build a class D power amplifier

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Driving LED arrays with arduino 

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House-Monitoring Framework with Arduino and Raspberry Pi: The Paranoid App

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Do-It-Yourself Soldering Station with an ATmega8

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Enjoy!

Arduino LED coffee table

Hello again my fellow readers. Today I present you an older project of mine, the LED coffee table.

The most difficult part was building the table itself and putting all the leds manually in their place.

The schematic and working principle is really simple. It would be very impractical to connect each led by itself, we would need 64 pins from the microcontroller. A better way to do this is by making a matrix, like in the picture below.
LEDM88G_Circuit

We now only need 16 pins, which is easy to manage. The problem in this configuration is that we cannot light up 2 or more specific LEDs without turning on some that we don’t want. If we turn on led[2,2] and led[3,3] we will also light up led[3,4] and led[4,3]. To do this, we only light up one row at a time very fast, so the human eye cannot see. This is how modern display works. In this project, we first ground the first row, turn on the led we want, then go to the next row, until the 8th, then repeat.

For this project I chose to use the very popular ATMEGA328, but we won’t hook up the matrix directly, we will use a shift register. Shift registers are really smart things, u send bits to them, either 1 or 0, which will turn on or off pins of the shift registers. For example if we send 00000001 it will ground every pin, except the last one, who will be VCC (usually 5v). I won’t go into further detail, you can read about them on wikipedia. Below is the schematic I used.

schematic

ATTENTION! I need to make one small remark. In my design, I also hooked the shift register outputs to transistors, and then to LEDs, because they cannot sink a lot of current. This design is ok if you want to use a chinese 8×8 led matrix, but for other LEDs please use transistors. (NPN for row / PNP for columns, but u can change this in software).

Here is the arduino sketch (it has some commentary, ask if you need anything, you can change the update speed for example) and this is a html page that generates patterns (credits to this instructable, I just modify it to be 8×8 ), just save it as patterns.h and put it in the same folder as the sketch.

Someone on reddit asked me “The LEDs seem far away from the top.. Is there a reason for that?”.

I didn’t use normal LEDs, but the ones with a flat top which have 100° viewing angle (normal LEDs have 30° if I recall correctly).

Then with a bit of clever math I calculated exactly how deep I will have to put the LEDs for a specific size of my table.

Let’s say we have a square of l = 5cm. The diagonal is l√2 (we need diagonal because we light up even the corners) and then we imagine a triangle like this, in the bottom is the LED (50° because it is only half). We apply tan(50) = 5√2/2 (only half, remember) / X . X is our height or how deep we have to put the LED and in this case is equal to aproximate 4,20.

Below is the video I made and some pictures. Enjoy!

PS. I know this is just very basic information, if you need any help, please ask in the comments below. I will try in the future to edit the code to read the pattern from a SD card or update it via wifi (ESP8266 🙂 )

The underside of the table

The underside of the table

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In the dark

In the dark

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Ignore crocs please

Ignore crocs please

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Prusa i3 – FDM 3D Printer

Hi there! I just finished my 3D printer and wanted to share with you.

I didn’t buy a kit, I don’t recommend you do, I sourced the parts from ebay/aliexpress/local. I’ll attach my BOM.

The printer is a Prusa i3 rework . Not the best design but well suited for a first printer. I’ll just post some pictures for now and present more details later.

Here it is, my BOM . It totals to about 350$, with 10$ for some miscellaneous parts I bought locally or had already sitting, like some files (tool), cables, etc. You could go waaay cheaper, just buy an acrylic frame (although I highly disagree of it!!!) and a cheap E3D v6 clone for like 8$, but just buy the real thing. I got the E3D V6 lite and had no problems (except a burnt heater cartridge). A good hotend is a must if you want to save yourself a big headache.

Printer Working

Printer Working – Click to open GIF

Finished item

Finished item*

Some parts for the printer

Some parts for the printer

Aluminium frame and E3D hot end

Aluminium frame and E3D hot end

Almost finished

Almost finished

Back side

Back side

Wiring

Wiring

Frontside

Frontside

*Finished item may differ to the item the printer was working on in the gif

PS. Ty redditor 😀

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Heaphone amplifier

Work in progress :
headphone

Schematic here : http://sound.westhost.com/project113.htm

555 Automatic green house timer

Hello again!
A year ago I decided to make a fully automatic green house, but, because of no free time, I eventually backed out.
Anyway, before getting out of this project I made a circuit that will activate a water pump, for aproximate 2 minutes, every 24 hours.

I combined the circuit from here and the 555 timer monostable circuit from wiki.

You can see the result here :
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R8 – 3M will be the jumpper from a CD4060 output pin (in my PCB you can choose from 2-3) and 555 trigger (pin 2) .
To change the duration of the “on time” you will have to modify the R7 and capacitor value (100k and 1000uF in my version).
This is the equation from wikipedia, where t is in seconds, R is in ohms and C is in farads.

To modify the time of the CD4060 , you have this table :

PIN Time
7 19 Second
5 38 Second
4 75 Second
6 2.5 Minute
14 5 Minute
13 10 Minute
15 20 Minute
1 80 Minute
2 160 Minte (2 hours 40 minute)
3 320 Minute (5 hours 20 minute)

I played with the capacitors, variable resistors and resistors values and i got 24h theoretically, practically I never tested.
Here are pictures of my resulted product :
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Here are the pcb layout, silk and components placement.
PCB layout
Silk
Component placement

If you want to build this you need to read the 555 time monostable and the page from the initial schematic because not all modification required are written here.

Credits to this site which, I again say, please read.

If you have any problem or question about this circuit leave a comment or send me an email (email in about page).

I hoped you enjoyed this and, as always, have a nice day!

LED light organ

Hello! I’m Cezar, also known as icamaster on some boards, and sometime, when i have free time, i build things.

In this blog i will post some of the things i build using a soldering iron, dremel, hammer and other useful tools. Enjoy!

I will starts with some videos i made a while back, soon i will add pictures of done projects with their specific schematic and pcb layout.

LED light organ – 3 channels

Schematic used by Collin @ MakeMagazine :

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PCB (by me) it’s a bit messy (in fact, it’s a big mess) but feel free to ask any questions.

It uses an TL074 (any quad op-amp will work) and TL071 (any mono op-amp like LM741 will work). Most resistors are in vertical position (this is my weakness) because i wanted to be as small as posible. Tranzistor can be any NPN, i used BC547 (fore more LEDs a more powerful one will be needed).

Outputs can be modified so the leds sit on the PCB (i will attach the files for Diptrace).

This is the pcb layout. (dimensions on the third link)

This is the silk.

Here are both with dimensions (you will have to either ask me or figure out how to put the parts that aren’t noted from the schematic, because I was too exited to get this finished when i first made it).

I hope you enjoyed this first post and, as i already said, feel free to ask me any question here, or at my email mini_cezarus@yahoo.com

Have a nice day!