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LED Flasher

For longer time I wanted to create simple controlled LED Flasher. For first version it’s preety big and needs more improvement. Basicly it is circuit with 555n timer few 2n2222 NPN’s, pots and LED’s.


It is constructed of four row’s with white LED’s . Each row has 6 LED’s in it that are all controlled with dedicated 2n2222 NPN transistor since one row pulls up to 120mA. In the end of each row there is diode to prevent backflow.


This is first version of circuit and that is because I don’t have any resisotors infront of LED’s and my potentiometer to controll input power was falsly rated. For connecting LED’s on bottom side of the board I used spare legs from resistors, in that case mostly got clean lines between LED’s. Red wires represent positive and black one’s negative side of circuit. Some joints are preety messy due to my soldering made on the floor freehanded.


Timing of LED flash ON and OFF if controlled with potentiometer and two radial capacitors rated at 50V. Schematics I drew does not have potentiometer for power control in it.


For video demonstration visit and subscribe:

My youtube chanel:

Direct video link:


Audio amplifier Onkyo Integra M5060R

To continue previous post with audio amplifier in this one I will took apart second amplifier Onkyo Integra M5060R. It is amplfier from late 1980′ with output power of 2x225W RMS. Front panel is 2cm thick peace of glass and total weight of amp exceedes 18kg. This amplifier I got for free many years ago and previous owner told me that it’s working without any problems.

Moment I came back home and turned it on ……… nothing happened. I took it apart and saw some burned parts inside. But the worse part was that the PCB overall looked like it was exposed to the rain with many dark dots on it.


Amplifier has 2 massive transformers on each side for each chanell. In middle there are 4 big capacitors with value 18.000uF each but unknown voltage.

I spoted one smaller capacitor that is leaking behind the big ones and some resistors on front panel. When I turned it over I spotted that sombody was allready messing around with ith since it has some very bad solder joints and the Power amps are different.

Here are some pictures of above mentioned amplifier from inside:






Audio amplifier RIZ P3060

For past few years I had two audio amplifiers that didn’t work and just rested in storage room. First one is from ex-Yugoslavia company named RIZ model P3060. I am not 100% shure but it should be 2x75W RMS. Other one is Onkyo Integra M5060R 2x225W RMS.


First I took apart RIZ one and well its preety old and dirty. The moment I opened it I saw that the main Capacitor is leaking on one side. It is very strange cap for me since on one side it shares same Ground pin but on other side it hat two Positive pins for output. Capacitor is rated at 2x4700uF at 40V.Image

Amplifier has one really big but light main transformer and only two glass fuses that are not even near the main input which is strange. Beside broken capacitor also front panel lightning doesnt wrok. If  you look closely to the line of resistors above main cap you can see that they have very strange texture like sombody spilled acid on them. They look more like moon surface then resistors.


Here are some more pictures of the amplifier above:




5V power supply for PIC microcontrollers

Month or two ago i have ordered PICkit 2 with board directly from MicrochipDirect. I must give really big credits for relations these people have with customers. I was talking to one kind lady which helped me out with payment, shippment and evrything, since i had compliations, not same shipping adress as billing one.

PICkit2 is quite old now and was replaced by PICkit3, some people are trashing about it some are still lifting PICkit2 to hights and some others like me dont really care, as long as it works. I think it is a great learning tool for a beginner and for some intermideate still eager to learn people. My kit came equiped with Microchips Mid-range microcontroller PIC16F690 it’s a 20 pin chip which you stick into 20 pin DIP  instead of directly soldering it. It is a good thing since if you blow it you can easly took it out and put a new one in, and also you can put other microcontrollers in like 10F, 12F, 16F and some from 18F family they produce.

PICkit2 has great feature and that is it can power up board that is conected to it, but what happens if you unplug it from programmer. Naturaly board is left without power. Easiest way would be to get a wall adaptor that has voltage settings and simply set it to 5V mode and stick it to  some 2.5 jack or somthing simillar.

Let’s say some people dont have wall adaptor like me and have only bunch of 9V batteries lying around, what to do in this case? Well here is simple solution 5V adaptor for 9V battery or any other powerdevices that are within specs of 5V regulator.

I took a smallest soldering board i could find and simply trim it to get even smaller. I populated it with 5V voltage regulator, one diode so just in case there is some reverse flow it doesnt do any damage to anything, one green LED to indicate if regulator is powered or  not and resistor to limit current to LED, other than that there are 2 pins on each side, one for input and one for output,

Underside i simply covered with hot glue, to give some protection from shorts and for better surface area besides that it also prevents slipping on any surface. I also hot glued some wire joints which can be seen on other pictures, reason for that was at the moment I don’t have shrinking tubes at disposal so i just imrpovised.

Green LED indicating power fed to 5V voltage regulator.

Finished product:

I tried to make schematics in program and i got as close as i knew, but there is one mistake on schematics and that is input and output pins. Schematics shows 5 pins but i couldnt find any other pictures to match my 2 pin layout.

If you want to see video presentation of it please follow next link:

Cabin Shower LED lightning

This project came up to my idea back when i moved to this new apartment. It has standing shower cabin without lightning, so i decided to put some in.  I have tried searching on youtube and google but I really havent found anything usefull that was made by the users itself and not by the manufacturers like IKEA with their LED kits.

As base i took that it had to be powered with 9V so that there is no real danger + i dont have any wall sockets nearby. To mount evrything i had to use glue gun (PATEX) since the shower cabin belongs to the apartment owner and not me, otherwise i would drill holes for LED’s and switch which would also give better inside lightning.

I used 4 bright white LED’s which i connected them in parallel via one small resistor close to switch, and glued evrything to the inside of the shower cabin. Hot glue also took care of some “water resistance” since I paid attention to cover all exposed wires and pins even on the battery and switch which is located outside. I glued Switch direclty to battery but this is just temporary solution. Battery and switch is mounted on plastic of shower cabin via some verlcro tape to avoid any damage to paint.

Overall result is quite good certantly not the best, it would definitly be better with 2 more LED’s somehow directed to the cabin cealing. All in all costed me almost nothing, i got 100 LED’s from broken light bulb(220V), 2x 9V batteries for 1€ and the switch i had in stock (about 1€+)

I made shure that cables have enough free movement with sliding door closing and opening

Sorry for bad picture quality that is all my Iphone can do in darker conditions.

If you would like to see video of evrything in action feel free to clik on following link:

Resistance Touch Sensor

What is resistance touch sensor circuit?

It is a simple circuit designed to turn on or off a device on output or too put IC in High or Low state.

How it works?

It works by sensing (when you touch anode and cathode) and on that basis it activates or deactivates a device that is connected to the output in circuit. In my example it works like this.

When a user touches the “resistance touch pad” that is in one end connected to positive (9v) and another end is connected to transistors(BC547B) Base, the flow of “electricity” activates transisotor which in this case starts to conduct and activates LED’s that are connected to transistors emitter via resistor.

For better understanding it would be easier just to connect 1 LED via 470 Ohm resistor but i like to complicate things without any reason.

I connected 5 Blue LED’s: First three are in parallel to each other and they are in serial with two other LED’s that are in parallel. In this case i used one 10 Ohm and one 22 Ohm resistor simply because i didnt have one 33 Ohm at disposal. Such a low value of resistors is also due to the reason that Touch pad is itself a resistor and LED’s cannot get full power from battery.

It is sensitive to the area your finger covers, and because this pad is years old and coroded it is also sensitive to the force applied 😀 dont get me wrong on this one.

Since the blue LED’s can have max values about 20-30 mA and around 4V i decided to put them trough 0.03A and in total about 5.5V across all LED’s in this case devided because of wiring.

Here is clearly visible the amount that is flowing trough the touch pad and as a result brighter LED’s

Smart idea would be to use limiting resistor between touch sensor and Base of transistor which i didnt use atleast not shown in pictures.

Next post should be about either HUM sensor switch or capacitance sensor switch.

Link to video version:

Questions and comments are wellcome

Newly multimeter and allready broken

As you all know recently i bought new digital multimeter Uni-T UT71D for about 150€. And after about a week now its starting to show problems and faults.

For instance yesterday multimeter was working normaly but today when i turned it on SURPSRISE 😀

When i select Resistance range on multimeter with probes unatached it is giving constant Error and beeping like crazy. Also when i set it to measure Capacitance and i hook up a capacitor it gives Error and constantly beeping. Same thing goes for Continuity when i touch probes it gives Error.

I really didn’t expect to see that happening so soon , more or less i didnt expect it to happen in near future but this just proves the quality you get from some cheap China brands with preety packaging.

I will definetly conctact the buyer about this and demand money back since this is absurd.

Here is link to quick video demonstration of faults i described above:

If you like it feel free to subscribe to my Youtube chanel.

Multimeter UT71D from Uni-T flaws

I decided do check my new multimeter little bit indepth and to see if there are any big flaws in it. And yes there are many major flaws that can harden the work with some small current or voltage circuits. For instance do not trust what Uni-T has written on their official webpage about the info of theri multimeter. It is very lousy multimeter and i feel relly sorry that i paid 150€ for it.- Nowhere on webpage or in manual it is described what is the range of HOLD PEAK,  MAX/MIN and how does HOLD function work. This part is very decieving from side of company since potential buyer would think that multimeter can measure PEAK and MAX/MIN like it is rated, but no multimeter can measure maximum from – 4V to +4V, not even on main desplay. When you put more than 4V it give you overload.
– When using function MAX/MIN without anything connected to the probes, as soon as the button is pressed, multimeter gives some random values on MAX and MIN side like -0.064V  and +0.154V and with that fault how can user measure somthing accurate if it is not set to -0  +0V?
– Hold function with normal meter is made so when the user presses HOLD multimeter waits for the user to connect probes to circuit and multimter should record the value that it gets feedback from probes. But this multimeter when you press HOLD it just instantly freezes display doesnt matter if it is conencted or no it just holds whatever is on display.
– Same goes for the PEAK HOLD same problems as HOLD function plus it can go max to -4V to +4V, and on begining it gives random numbers.
– On the PCB between input jacks fro 10A and 400mA  there is big screw inside PCB and somthing is soleder between. With that there are two problems. 1st It give no Spark gap between inputs, and 2. it is lousy job which also diferentiets resistance trough trace and just to solder some part on screw is really low quality work.- When switching between ranges probes give some output, havent measure it yet but it is enough that LED blinks if it is connected to them. I dont really think this is healthy for some delicate circuits.
Based on my multimeter if others are like this i strongly recommend DO NOT BUY PRODUCTS FROM UNI-T!!!

Three transistor AND Gate (FAIL)

Today i tried and i am still trying to figure out how to make AND gate with 3 transistors (NPN). I tried switching T3 transistor to simple mosfet since it needs higher current on base to go to high state but i ended up with same result. LED 1 and LED 2 will work according to wich button is pressed but LED 3 is dead non stop. Any ideas what should be the reason for my failure. I belive it’s some simple mistake that i cannot see it clearly atm so please if you have any advice or explanation how and why please feel free to post comment.


Chart bellow is my idea how this circuit should operate

Button 1  | Button 2  | LED 3
ON          |      OFF      |   OFF
OFF         |       ON       |   OFF
OFF         |      OFF      |   OFF
ON          |       ON       |    ON

Multimeter Uni-T UT71D Teardown

Today my mail(lady) 😀 brought me a package…aaaa who doesnt love packages in the morning:D  Not to my surprise inside was item that I ordered on saturday: Uni-T UT71D Digital Multimeter. I could’t resist but to take some pictures of unpackaging and sort of  a teardown. All in all i can say for the first impression I am very satisfied. Found few flaws in my opinion but its jsut the way it is.
– Probe cables ar hard as hell guess they are made from tought plastic

– Continuity test fails all the way here 😀 even on my old multimeter without that function is better 🙂
– Not shure about following: Temperature leads doesnt look like to be “original” ones

Here are some photos of evrything.