Mini Operated Voice Relay Schematic

Mini Operated Voice Relay Schematic

Component Parts list:

R1, R7 1K
R2, R4, R8 10K
R3 2K2
R5 1M
R6 200K
R9 39K
D1, D4 1N4004
D2, D3 1N4148
C2, C5 2.2uF/16V mini ecap



C1 10uF/16V mini ecap
C4 100pF
C3 100nF
Q1 BC548
IC1 LM358 (of Hitachi HA17358)
8 pin IC socket
Relay AX-SH-112L
LED 3mm
Electret microphone

This mini-VOX – voice operated relay – is based on a circuit published in Silicon Chip, 9/1994, p31. The off delay time may be adjusted by varying R3 and R4. Reducing R3 will result in a longer release time. You could change the release time constant (C2 & R5) to say 30 seconds and use the VOX as a light switch with this delay time before turning off. Increase C2 to say 10uF and R3 to 3M3.

To make the easy adjustment, you may use potensiometer or trimpot to varying the value of resistor. You will need additional place on the PCB but it will easier for you to make some adjustment The kit of this circuit available at kitsrus.com anf electronickits.com, you may buy the circuit there.

HERE the manual instruction of this Mini Voice Operated Relay circuit

Read More → Mini Operated Voice Relay Schematic

MOSFET and Push Button Relay Toggle Circuit

This circuit is similar to the one above, but uses a N channel mosfet such as IRF530, 540, 640, etc. in place of the NPN transistor. Smaller mosfets could be used, but I don't know the part numbers. I tested the circuit with a IRF640, IRFZ44, IRFZ34 and REP50N06.

The circuit has the same three advantages, it requires only a few parts, always comes up with the relay deactivated, and doesn't need any switch debouncing.

In operation, when the relay is deactivated, the 100uF capacitor will charge to 6 volts. When the button is pressed, the capacitor will apply 6 volts to the MOSFET gate turning it on. The capacitor voltage (and gate voltage) will fall from 6 to 3 volts in about 200 mS which should be enough time for the relay contacts to move. For very slow relays, a larger capacitor may be needed.

When the relay energizes, the contacts will apply 12 volts to the 3.3K resistor producing 6 volts at the gate, which will keep the relay energized indefinetly. The capacitor will now discharge to zero since the +12 relay contact is no longer connected to the 15K resistor.

When the button is again pressed, the capacitor will apply zero volts to the gate turning off the relay. There should be no problem holding down the button causing the relay to re-engage since the gate voltage will be only about 1.8 volts when the button is held down and the mosfet requires about 3.5 volts or more to start conducting. But you do need to wait about 1 second or longer between button presses, so the capacitor has time to charge or discharge. Two push buttons are shown, but you could have several more in parallel to control the relay from several different locations.

Read More → MOSFET and Push Button Relay Toggle Circuit

PIC12F629 Decoded IR Toggle Switch Circuit

The circuit above illustrates using the IR receiver module along
with a PIC12F629 microcontroller to decode 5 individual IR remote
control keys so the circuit will only toggle one of the 4 outputs
when a particular key is pressed. The 5th key is assigned to the
master clear function that toggles off the 4 outputs. Works with
most hand held IR remote controls that send a single data stream.
However, some remotes send multiple groups of data and only the
first set of 40 bits or less will be recognized. This may result
in the circuit responding to more than one key, or a single key
may control more than one toggle switch. In most cases this problem
can be resolved by selecting an alternate function on the remote
such as (TV, DVD, SAT, AUX, Etc.). Circuit power supply is not
critical and should operate on any voltage from 2 to 5 volts DC.
I use a single 3.6 volt recharageable lithium battery such as
found in cell phones.

Setup instructions to program the controller and record the desired keys.

Step 1 - Remove power and install a jumper wire from the input
(pin 4) to ground.

Step 2 - Turn on 5 volt power to the circuit and the activity
LED will flash 3 times and remain on.

Step 3 - Remove the jumper from pin 4 and the activity LED should
flash three more times and remain on.

Step 4 - Press the desired keys in sequence to record the keys.
The first key must be pressed twice to allow the program
to establish the timing on the first press. So to program
keys 1 to 5 you would press 1,1,2,3,4,5. At each keypress,
the indicator should flash 3 times and remain on.

Step 5 - At this point, the indicator light should be out and
you can test each key to verify it toggles the correct
output. The data is stored in no-volitile EEPROM so
when the circuit is re-booted without the jumper it

should be ready to use with the existing programed data.

For test purposes, you may want to install LEDs and resistors
on the 4 outputs to verify correct operation.

----------------------- PIC12F629 HEX File ----------------------

:10000000000000008A0107309900850183169F01D6
:10001000C83085008312A501A901A701A201A70A82
:10002000FA30AA00453084001A30A000A30123084A
:1000300083169B001C141A0883128000840AA30AEA
:10004000A00B17281821851956285D308400193017
:10005000A00080018403A00B2928851D2D281821CC
:1000600085193028851D322885193428B401851D4D
:100070003728A50185194C282508031034020318D8
:1000800044282508B4003728250803102A02031C39
:100090004B282508AA004328A50A0821A51B51289A
:1000A0003A282A08B407340CDE00A915C001C101A2
:1000B000C201C301C401A9191821A91D05112210EB
:1000C0008519602805154030A91D7528A70DA718AA
:1000D000453027194A30A7194F30271A5430A71A2C
:1000E0005930271F7528A701A70AB40184000830DA
:1000F000A600851D792885197B28A501851D7E28E8
:10010000851D882808210311A50A03199A2880282B
:100110002830340603197D28B40A0310800D5E08C8
:100120002502031800140310A60B9928840A08302E
:10013000A6007D280311A919E228B001A10105300C
:10014000A0000530B0074030B10022103108AE00E9
:100150003007AF00D720B10AA00BA6282108B7208E
:100160000630A1071E302106031D9F28E228221811
:10017000080082078518BE288514BF28851008004E
:10018000051AC4280516C52805120800851ACA28AC
:100190008516CB28851208000518D0280514D1280B
:1001A00005100800851205128510051008002E089C
:1001B00084000008B2002F08840000083206031DE6
:1001C000221408000D210D21A91D5628A71E56280E
:1001D0001930A000A300A30A5E3084000008831633
:1001E0009A008312200883169B001C1555309D0031
:1001F000AA309D009C1483128C1FFC288C131C11A8
:100200008403A003A30BEE28A701A70AA90156287F
:100210000F30A300A30B0A290800FF30A300132905
:10022000A30B13290800FF30A000A00B15291029EB
:1002300005110D2105150D2105110D2105150D21A6
:0A02400005110D2105150D21080020
:02400E00043F6D
:00000001FF

Read More → PIC12F629 Decoded IR Toggle Switch Circuit