3V DC to 5V DC REGULATED POWER SUPPLY ELECTRONIC DIAGRAM

3V DC to 5V DC REGULATED POWER SUPPLY ELECTRONIC DIAGRAM

A 5V DC regulated output from 2 cells 3V DC batteries. The output current of the circuit is limited to 50mA. However, it still able to supply many microcontroller circuits. 3009 and 560R Resistor provide the 5V DC output, make up a voltage divider network.

Read More...

AUDIO LEVEL METER ELECTRONIC DIAGRAM

AUDIO LEVEL METER ELECTRONIC DIAGRAM

It consists of only few components. IC LM3915 converts the audio analog voltage and display it to the LED. Here is the schematic :

Parts list :

•     Resistor R1 : 1k2
•     Resistor variable R2 : 10k
•     IC : LM3915
•     LED indicator LED1-LED10 : LED 5mm
•     12V power supply

Read More...

Electronic Touch Switch

Mechanical contacts have the disadvantage that they wear out. That is why it is practical to use an electronic ‘touch switch’ in some situations. With such a touch switch the resistance of the human skin is used for the switching action. The schematic shows the design of a circuit that senses the resistance of the skin and converts it into a useful switching signal. The touch switch contacts can be made from two small metal plates, rivets, nails, etcetera, which are placed close together on a non-conducting surface. In this circuit a comparator of the type LM393 has been used. In the idle state there is, via R1, a voltage equal to the power supply voltage on the non-inverting input of IC1a. Because the inverting input of IC1a is set with R2 and D3 to D5 at the supply voltage minus 1.8 V, the open-collector output of IC1.a is, via R3, equal to the power supply voltage. This voltage is inverted by IC1.b. The voltage at the non-inverting input of IC1.b amounts to half the power supply voltage (through voltage divider R4 and R5) and is lower than the voltage on the inverting input.

Circuit diagram:

Electronic Touch Switch Circuit Diagram

The output of IC1.b is therefore a ‘0’. If the two touch contacts are bridged with a finger, the voltage at the non-inverting input will become low enough to cause the comparator to toggle state. The moistness of the skin results in a resistance of 1 to 10 MR. If this circuit is used in the vicinity of equipment that’s connected to the mains, then it can be sufficient to touch only the upper contact to operate the switch, provided that the circuit has been earthed. The body then acts as an antenna which receives the 50 Hz (or 60 Hz) from the mains. This is enough to toggle IC1.a at the same 50 Hz. C1/R3 prevent this 50 Hz from reaching the input of IC1b and provide a useable ‘pulse’ of about 10 s at the output of IC1.b. Note that a fly walking across the touch switch conducts enough to generate a switching signal. So do not operate important things with this circuit (such as the heating system or the garage door). Do not make the wires between the touch contacts and the circuit too long to prevent picking up interference. The power supply voltage for the circuit is not very critical. Any regulated DC voltage in the range from 6 to 20 V can be used.

Author: Heino Peters - Copyright: Elektor Electronics Magazine

Read More...

CHALLENGES DESIGN OF SWITCHING LED ELECTRONIC DIAGRAM

CHALLENGES DESIGN OF SWITCHING LED ELECTRONIC DIAGRAM

The LED WEBENCH® online design environment predicts and simulates the response of an LED to constant current while taking into account several potential design parameters that are new to designers of traditional switching regulators.

Read More...

How to Build a Pyro ignition Circuit Electronic Pyro Igniter system

The
following conversation was made by Mr.Tom and me regarding the circuit
idea of a pyro-iginition system. I was asked to design
the particular circuit idea by Mr.Tom in Fiverr.com.
The discussion explains the details of his requirement and how it was almost fulfilled by me
I was wondering if you could design me a system for a simple pyrotechnic firing system. 
An input trigger would (maybe 5-12v) pulse would switch on que1, another pulse would switch cue2 (binary counter). 

A
total of 16 channels (cues), each cue would be fired with from mosfet
pair. Ideally control circuit would have independent power supply to
power to cues. 

It
would also be nice to have a timer which could on pulse fire each cue
in sequence e.g. cue1 wait 1 second cue 2 wait 1 second cue3 etc. 

Either this of some kind of programmable pic (picaxe etc) so the functionality can be changed. 

Kind regards 
Tom

Hi Tom,
I
can design the control circuit along with the timer, however Im
interested to know what would be connected to the mosfet outputs,
because that looks the difficult part if Im required to set up those.

Thanks
Swagatam

Heres the pyro-ignition control circuit:

Next up is the mosfet output stage:

Hi Swagatam,
I dont seem to be able to get the control circuit to work.
Where does the external trigger connect to, if i connect a ground just before R5 can I use this as the trigger?
Thanks
Tom

Hi Tom,

The circuit starts sequencing the moment power is switched ON, so the "power ON" switch itself acts as the external trigger.

When
power is switched OFF, the circuit resets and comes to its original
state, so that when power is switched ON again, the cycle can repeats.

Thanks,
Swagatam

Hi Swagatam,
Thats not what I asked for.
The external trigger should either start the timing sequence if selected or step through each output on each trigger input.
Referringback to the conversation
"
Function 1
Trigger -> Cue 1 fires (stays on for 100ms to ignite firework)
Trigger -> Cue 2 fires (stays on for 100ms)

Function 2
Trigger -> Fires all Cues in sequence (cue 1,2,3 etc) from a internal modifiable timer

Function 3
The
circuit diagram also has continuity test for each cue, this should be a
low enough current as not to fire igniter this is to be displayed
through an led on each cue.
"

Regards
Tom

Hi Swagatam,
Ive attached a circuit diagram of an open source wireless firing system, the files can be found here
http://code.google.com/p/openpyro/downloads/list.
The system will fire these http://www.category4.co.uk/igniters/technical/igniters.php
If
youre just using a binary counter I think you might need to double the
stages(bits) and pulse the clock after 100ms to turn off the mosfets in
case of short circuit.

If you could replicate attached circuit without the wireless this would be fantastic. Ill pay for extra gigs if needed.
Thanks
Tom

Hi Tom,
From the above description what I understood is that the particular fireworks needs to be ignited in some sequence.

The
fuses would be loaded across the relevant mosfets and the triggering
timing would be such that the mosfets are switched only for some
fraction of a second, just enough to ignite the fireworks and then shut
off.
The sequence will go on repeating until the last mosfet is fired...am I correct?
If
my interpretation is right then I can go ahead with the circuit and
design it using ordinary discrete components, no need of any
microcontrollers.

Thanks,
Swagatam

Yes,
Function 1
Trigger -> Cue 1 fires (stays on for 100ms to ignite firework)
Trigger -> Cue 2 fires (stays on for 100ms)

Function 2
Trigger -> Fires all Cues in sequence (cue 1,2,3 etc) from a internal modifiable timer

Function 3
The
circuit diagram also has continuity test for each cue, this should be a
low enough current as not to fire igniter this is to be displayed
through an led on each cue.

Could this led be also lit when the cue is fired.
Tom

OK, function1 refers to a manual triggering option in the circuit? right?

There should be power to the circuit at all times, when a plus trigger is applied to the system it should step.

Hi Tom,
In our circuit this can be done through a simpler modification, kindly view the attachment.
Pressing S1 initiates the sequencing at any instant and releasing it stops the process.

Thanks
Swagatam.

OK let me try an explain again.
The circuit is a stepper, each trigger pulse it receives progresses the binary counter on one.
So trigger +12 v, binary counter increases one.
Trigger again +12v, binary counter increases one again.
The trigger pulse it totally separate from this circuit and comes from another source.
Easy enough, just a binary counter and outputs.

I
also want another function to allow the first trigger pulse to start a
timer a clock the binary counter on its own. This time is variable. So
there would be a switch to allow you to access this mode. So binary
counter output 1 would feed back into the timer circuit if a switch was
closed.

Hi Tom,
Just have a look at this modification, I hope this one works as intended.
S2 is a SPDT switch, when positioned toward B, it responds to the pressing of S1 and steps with each trigger from S1.
When S2 is moved toward A, pressing S1 does the following things:
T1 and T2 instantly latches powering the timer IC 4060 via T2 and T3.
IC 4060 starts clocking the IC 4017 for the required actions.
Putting
S2 back to point B resets the circuit to its previous mode, that is to
the manual mode. However to reset the IC 4017, it will need to be
switched OFF and then switched ON again.

Read More...