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Hi all!
This instructable not only gives the reader the information needed to create a clap-clap on/clap clap off switching circuit, but the logic used to make a hardware-only clap-on, clap off circuit.  More information on a hardware-only version can be found in the final section of this instructable.

This circuit employs some very simple and cheap circuitry, and a simple program. It is relatively easy to make a hardware only clap on/off circuit, but I wanted to create a circuit that required two claps to switch on, and two claps to switch off.  The claps must be in quick succession, as seen in the video below, or else it does not work, which is the entire point of the circuit =)  I will go into detail about the circuitry, and the program.  I will also do my very best to answer any questions you guys may have.  This device can be thrown together in a single evening.

The software works like this:
1) The software waits for an initial loud noise, then starts a countdown sequence.
2) If the device detects another loud noise within about 250 milliseconds, then the relay will toggle on.  If the timer runs out of time without detecting another loud noise, the program resets.
3) Once two claps have been detected, and the relay toggles on.  The software then starts the same sequence over again, only waiting to toggle the relay off. 
4) Once the relay toggles off again after detecting two claps in succession, the program resets back to the original state.

Since the PIC10F222 has a limited instruction set, I had to add in some extra lines of code.  I would have used the PIX18F1220, but that would have been over-kill.  Ah, but how I miss the BTF (Bit Toggle) instruction =)

Step 1: PART LIST:

HARDWARE:
I'll start of by giving you guys a part list.  The box and the screws are not necessary for this project, but I'll add them to the list.

PART LIST:
1x  Prototyping board (Roughly 1" by 1") or bread board.
1x 9v Connector
1x LM324 Quad Op-Amp IC
1x LM78L05 Mini 5v Regulator
1x PIC10F222 Micro controller
1x Electret microphone
1x 5v Relay SPDT or SPST
1x 2N2222 NPN Transistor
2x 0.1uF Ceramic capacitors
1x 1N4001 Diode
1x 100k Ohm Multi-Turn Potentiometer
1x 100k Ohm 1/4W resistor
2x 10k Ohm 1/4W resistor
1x 3k Ohm 1/4W resistor
1x 7k Ohm 1/4W resistor
1x 1k Ohm 1/4W resistor
1x Project Box
 

Step 2: THE POWER SUPPLY

THE VOLTAGE REGULATOR:
This step is a short one.  We're going to talk about the power supply circuit. 
We only need a 9v battery to properly drive this circuit.  We can use 7VDC and up.  The 78L05 5V regulator is used here because this is a low-power device, and we need not use a big LM7805 when we have so little space to begin with.

The 78L05 has three pins:
1) 5V-Out
2) Ground
3) Voltage-In (7VDC+)

We need only a 0.1uf ceramic decoupling capacitor between the 5v-Out line, and ground to rid the circuit of any unwanted high frequency interference that may come along.  However, since we are using a battery, this capacitor is really optional.  Good practice, more like.  If you are using an AC-DC wall wart, it is suggested you place a 100uf electrolytic capacitor between the Voltage-In pin, and the ground line to protect against any surges on the line, and to smooth the DC going in to the regulator.

Step 3: THE SIGNAL AMPLIFIER AND COMPARATOR

STAGE#1: The Microphone and the Amplifier
As you can see from the picture below, we have an electret microphone connected to the ground line, and to one end of a 10k resistor.   The other end of the resistor is tied to the 5v line.  when an audio sound is sensed by the micrpphone, it changes that audio signal into a voltage that emulates the tone picked up.  We can use that noise, but first we have to condition it.  To rid ourselves of the DC component, we AC-couple the signal using a coupling capacitor.  This signal will be extremely small, so we must first amplify it.  We are going to do that using a handy-dandy LM324 quad op-amp IC.  This chip has 4x on-board op-amps.  We are only going to use two of them.  Go here for the data sheet: http://www.national.com/ds/LM/LM124.pdf

The pull-down resistor to the right of the coupling capacitor is necessary for the operation of the non-inverting amplifier stage to work.  In fact, all components in the below diagram are crutial.  The way a non-inverting op-amp works, is it takes two values RA, which is the 1k resistor connected to the (-) input and ground, and RF (100k potentiometer), which is the feedback resistor, which is connected between the (-) input, and the output, and creates a voltage gain factor.  The voltage gain factor (AV) is a multiplier.  Once we determine the AV, we multiply the voltage at the input by the AV, and we have our output voltage.  The 100k pot is used to vary the voltage gain.  This will either increase the sensitivity or decrease the sensitivity of the circuit.  The equation for AV = RF/RA in a non-inverting amplifier circuit.

Example#1
RF = 100k
RA = 1k
Vin= 0.010v
AV = RF/RA
AV = 100
Vout = Vin * AV
Vout = 1v (Gain of 100)

Example2:
RF = 1k
RA = 1k
Vin= 0.010v
AV = RF/RA
AV = 1
Vout = Vin * AV
Vout = 0.010v (No gain)

STAGE#2 The Comparator:
The standarad MCU does not like to work with sine waves, or any odd shaped wave.  That is, unless you are using the ADC, which we are not.  We want to turn our now amplified waveform into a 0-5VDC square wave that can be used by the PIC10F222.  What are are going to emply here is the comparator circuit.  A comparator does exactly as you'd think.  It compares voltages.  If the voltage at the (-) input is higher than the voltage at the (+) input, then the output will be 0v.  If the voltage at the (+) input is higher than the voltage at the (-) input, then the output will be 5v.

We have a resistor voltage divider network at the negative (-) input.  This will keep a constant 1.5v at the negative input.  When a loud sound is generated and amplified to a voltage higher than 1.5v, then the output will go from 0-5v until the voltage at the (+) falls below 1.5v.  We only need for the output of the comparator to be high for a micro second or so, so don't worry too much about the time duration of the output of the comparator being high.

You can change the resistor network around to make the reference voltage at the negative input (-) higher or lower using this formula:

R1 is the resistor tied to the 5v line, while R2 is the resistor tied to ground. 
V(-) = [VCC / (R1+R2)] *R2
V(-) = [5v / (7000+3000)] x 3000
V(-) = 1.5v

 

Step 4: THE BRAIN AND THE THE RELAY SWITCH

THE BRAIN (PIC10F222):
Ah the good ol' archiac PIC10F222.  This chip has an on-board internal oscillator, which exterminates any necessary external driving hardware, such as a crystal oscllator.  We really only need 5v, Ground, the output of the comparator, and an I/O port dedicaated to controlling the driving of the relay.  So we are only using 4 out of the 8 pins.  Read the software section to see how the chip is interpretting the comparator information, and how the algorithm is set up.

PIN-OUT:
Pin#2 = VCC (5v)
Pin#4 = GPIO,1 (Programmed as an input)
Pin#5 = GPIO,0 (Programmed as an output)
Pin#7 = Ground

The Relay Switch:
In order to drive our 5v relay using the output of a PIC, we have to set up a driver circuit, which in this case is a simple NPN transistor, and a diode.  The diode does nothing to drive the relay, but it acts to protect the relay coil from surges.  Any coil such as this should always be protected by a diode.  The 1N4004 is as good as any.  The base of the transistor is protected by a 10k ohm resistor.  You want to make sure that you are using this, or else you will over-drive your transistor.  When GPIO,0 outputs 5v (high or set), then the base of the NPN transistor is activated, allowing 5v to pass through the internal coil of the relay, and thereby creating a magnetic field that toggles the internal switch.  When GPIO,0 is cleared (0v), then the transistor is deactivated, and the path from 5v to ground along the coil stops dead.   The magnetic flield then collapses, and the relay swiitches back to default state.  In other words, if you used the configuation below, you have 5v at the common wiper of the SPDT (Single pull double throw) relay.  In default setting, the wiper is connected to the NC (Normally connected) pin of the relay.  when the relay is activated, the wiper connects to the NO (Normally open) pin of the relay, and power is applied to the LED.  When the relay is deactivated, the wiper re-connects to the NC pin, and the path from 5v to the LED is broken.

Step 5: SOFTWARE

THE PROGRAM:
I have done my best to comment out this program as best as I could.  You should be able to follow along.  It is no masterpiece, but again, I was working with an inferior instruction set.  You can download the .ASM code and use it with your PIC ICD2 programmer puck, as seen in the image.  I am also happy to answer any questions you may have relating to the software! 

The ASM code can be downloaded here: http://www.electroniclessons.com/10F222TMPO.ASM



*********************************************************************************************
MAIN    CODE    0x000
MOVWF   OSCCAL            ; update register with factory cal value


INITIALIZE
MOVLW B'0010'        ; GPIO1=COMPARATOR IN - GPIO0-RELAY ACTIVATE
TRIS GPIO                 ; INITIALIZE
CLRF ADCON0        ; ADC DISABLE
CLRF GPIO               ; CLEAR OUTPUTS
MOVLW B'00001000'
OPTION                      ; ENABLE GPIO2 AS A DIGITAL PORT    

SCAN1:
BTFSS GPIO,1           ; CHECK TO SEE IF LOUD NOISE (CLAP IS DETECTED)
GOTO SCAN1            ; IF NOT, SCAN AGAIN (LOOP)
ENSURE:
BTFSC GPIO,1           ; HAS THE WAVEFORM GONE FROM HIGH TO LOW?
GOTO ENSURE         ; IF NOT, CHECK AGAIN (LOOP).  IF SO, GOTO NEXT INSTRUCTION
CALL LOOP1              ; DELAY
COUNTDOWN:          ; COUNTDOWN ROUTINE
MOVLW 0XFF             ; LOAD REFERENCE VALUE
MOVWF TEMP5         ; LOAD TIMING REGISTER#1 WITH REFERENCE VALUE ABOVE
MOVLW 0XFF             ; LOAD REFERENCE VALUE
MOVWF TEMP6          ; LOAD TIMING REGISTER#2 WITH REFERENCE VALUE
COUNTDOWN2:        ; ACTUAL DOUNTDOWN ROUTINE
BTFSC GPIO,1           ; CHECK TO SEE IF LOUD NOISE IS APPARENT.  
GOTO RELAYACTIVATE     ; IF YES, ACTIVATE RELAY (TOGGLE)
DECFSZ TEMP5                  ; IF NOT, DECREMENT COUNTER#1  IF REG=0, SKIP NEXT STEP
GOTO COUNTDOWN2       ; GO BACK AND LOOK AGAIN FOR SECOND LOUD NOISE
MOVLW 0XFF                        ; LOAD TIMING REGISTER#1 WITH FULL VALUE AGAIN
MOVWF TEMP5                    ; LOAD
DECFSZ TEMP6                  ; DECREMENT T-REGISTER#2
GOTO COUNTDOWN2      ; IF TIMING REGISTER#2 IS NOT Z, DO SECOND SCAN AGAIN
GOTO SCAN1                      ; IF TIMING REGISTER#2 WAS 0, GO BACK TO START

RELAYACTIVATE:
BSF GPIO,0                  ; ACTIVATE RELAY
CALL LOOP1               ; SERIES OF 3 DELAYS
CALL LOOP1
CALL LOOP1
; THIS NEXT SEQUENCE IS JUST A MIMICK OF THE FIRST SEQUENCE, ONLY WE ARE
; WAITING TO TOGGLE THE RELAY BACK TO ITS ORIGINAL POTISION.
; I HAVE ADDED IN A SHORT DELAY AT THE BEGINNING, DENOTED BY ***

SCAN2:
CALL LOOP1         ; ***   SERIES OF 3 DELAYS
CALL LOOP1
CALL LOOP1
BTFSS GPIO,1
GOTO SCAN2
ENSURE2:
BTFSC GPIO,1
GOTO ENSURE2
CALL LOOP1
COUNTDOWN3:
MOVLW 0XFF
MOVWF TEMP5
MOVLW 0XFF
MOVWF TEMP6
COUNTDOWN4:
BTFSC GPIO,1
GOTO RELAYDEACTIVATE
DECFSZ TEMP5
GOTO COUNTDOWN4
MOVLW 0XFF
MOVWF TEMP5
DECFSZ TEMP6
GOTO COUNTDOWN4
GOTO SCAN2

RELAYDEACTIVATE:
BCF GPIO,0                  ; DEACTIVATE RELAY
RESET                           ; RESET PROGRAM

LOOP1:
;THE LOOP ROUTINE WORKS LIKE THIS.  WE LOAD TIMING REGISTER TEMP1/2 WITH 8-BIT
VALUES, AND IT WORKS TO ESSENTIALLY COUNT DOWN THE FIRST REGISTER, AND
WHEN THE FIRST REGISTER IS 0, THE PROGRAM DECREMENTS THE SECOND TIMING REGISTER (TEMP2).  AT THIS POINT, THIS KEEPS ON DOING THE SAME THING UNTIL TEMP2 REGISTER VALUE = 0, AT WHICH POINT, THE DELAY ENDS, AND WE GO BACK TO THE PROGRAM.

MOVLW 0X00
MOVWF TEMP1
MOVLW 0XF0
MOVWF TEMP2

LOOP2:
DECFSZ TEMP1
GOTO LOOP2
DECFSZ TEMP2
GOTO LOOP2
RETURN

END
***********************************************************************************************

Step 6: THE CONCLUSIONS!

THE CONCLUSIONS:
I didn't think that this project would be so simple, but I ended up designing it as I built it.  The hardware took about two to three hours, and the software took less than an hour.  Some slight modificaitons had to be made along the way, but over all, the entire project was put together in one night.  If I had a more recent PIC to work with, the program would have been MUCH more efficient.  However, the program works perfectly.

I've build clap-on, clap-off circuits before, but never one like this.  I hope that if you liked it, you'll vote for it = )

DON'T WANT TO USE SOFTWARE?
Try this on for size.  Create the exact same power supply circuit (You can use a 7805 if you want), the same microphone circuit, and the same amplifier/comparator circuit.  Buy a 555 timer, and a TTL JK flip flop such as the 74LS76 or the 74LS109A (My favorite). 

1) Configure the 555 timer as a monostable multivibrator with a delay of about 100-500ms.

2) Configure the JK flip-flop so that is works in toggle mode.

3) Place a POR (POWER-ON-RESET) on the flip-flop IC so that it will start in a known state.
If you don't know about POR circuits, google one.  It is a circuit that essentially clears a digital device for a short period on power on, so that the output will start in a known state.  Sometimes, decoupling caps don't do the trick, and the start-up spike on power-on will mess with the chip function.

4) The signal coming from the comparator will be a square wave, but it will be a frequency, rather than straight DC.  We need to turn this square frequency 10101010101 into a single pulse 01111111110.  This is done using a monstable multivibrator.  A 555 timer will do, and the data sheet will show you how.  The monostable circuit, when triggered will offer a single pulse.  This single pulse will be ideal for acting as a trigger to toggle our JK flip-flop.  It will require a timing RC network, comprised of a single resistor and single capacitor. 

5) If you don't know about JK flip-flops, they can be configured to act many different ways,  You have to set it up into toggle mode.  This can be done by looking at the data sheet.  It will show you a configuration set-up for toggle mode.  it doesn't require any external hardware, except some wires.  

The single pulse from the monostable will trigger the flip-flop, which will act to toggle it's output.  The output can be connected to a relay driver exactly like the one seen in STEP#4. That is a single clap-on, single clap-off circuit.  If you have any questions, I am happy to help..

                                                   THANKS FOR LOOKING EVERYONE!     
<p>good</p>
Can somebody please tell me how to design a clap switch which turns on by two claps and turns off by one clap?
<p>You have to code like that in 555 timer. For example for a electrical input you need to clap twice else reset the code right? After turning on circuit you need to code it to input signal when you clap only once.</p>
<p>hey can i connect it to a 220V source with same specifications of the circuit or do i have to change the resistors ?? </p>
<p>i want to use my arduino uno as microcontroller because i havnt worked on PIC10F222..</p><p>so, can I ?</p>
<p>This is a simple one clap switch circuit using 555 Timer</p><p><a href="http://electricaltechnology.org/2014/10/clap-switch-circuit-electronic-project.html" rel="nofollow">http://electricaltechnology.org/2014/10/clap-switc...</a></p><p>I hope it will help you... </p>
<p>I'd much rather build a circuit that uses the venerable ol' 555 and a tank circuit to time it. There's too much &quot;reach for the PIC, 'cause that sounds like a logic circuit to me&quot;- A $.50 circuit with $20 worth of supporting electronics. (I exaggerate, but not by that much!)... The timer doesn't need a PC and a programming puck - easy to wing it.</p>
<p>Thanks Bro </p>
<p>I just made this:</p><p><a href="https://www.instructables.com/id/The-Viciously-Simple-Clap-ON-Clap-OFF-Circuit-For-/#" rel="nofollow">https://www.instructables.com/id/The-Viciously-Simp...</a></p><p>I hope that you find it helpful!</p>
hey guys I need some help<br>my led goes automatically of after 5-6 seconds......how to fix it????<br>plzz reply
<p>Hello EngineeringShock! <br>Loved the detailed explanation with all the steps and schematics <br>Is it possible to make a HARDWARE ONLY triple clap on/triple clap off circuit based on this one? If so, how? <br>Thank you :)</p>
<p>i cant understand the complete schematic in step 6 .. anybody can explain .. ? thanks</p>
<p>Nice Instructable. How close are you to the microphone when you do this?</p>
do you have some scheme to connect it on 230V (or 110V for America) , or you can do it with that circuit then just connect it to some relay which will work as switch?
<p>Have you found an answer to your question? Because I'm going to use a 230V instead of a 9V and I'm wondering if I have to change something...</p>
<p>Yes, you can connect it to 230V with no problem, but under condition that you have 5V power supply for your circuit and relay ( if you're using the one which works on 5V) , on relays you can attach up to 380V(I think they are rated to this voltage) </p>
<p>can you please send me the hex file? I'm lost with asm compilation...</p><p>I really don't understand how to compile it. It will be awsome if you could send me the hex file</p><p>romainhuon514@gmail.com</p><p>thanks!</p>
<p>great post. Another alternative if someone does not want to program and code ; we can use a counter like CD4017 which counts the claps from LM324 output, and you can easily set 2 or 3 or even 4 claps on or off.</p>
U made one ?<br>
<p>good day all ..</p><p>thanks a lot for the great work, but I only have one question; what is the use of </p><p>100k Ohm Multi-Turn Potentiometer ? </p><p>thanks a lot and will be waiting for your answer :D</p>
<p>Seems that the code up there is not working Pat.</p><p>Assembler Code build failed</p><p>Can u make a video of compiling the code and share it to us Pat?</p>
Hello! I made the circuit but I have a question. What pins of 10f222 I have to use to programming it; I don't know very well the programming stage of circuits. Thank you!
Sorry for taking so long to get back to this, guys. I don't have the hex file available. Just the code posted in the instructable =( <br>Sorry! =(
Will it turn off by itself? If yes, how could I keep it from turning off by itself?
Hello! I'm new to electronics and was looking to make something like the clapper but that responds to other sounds. Does anyone know how to make one?
<strong>Nice instructables</strong>, but the project needs some engineering background i guess , or needs higher level of intellect in electrical or electronics, where ordinary hobbyist like me cant understand .&nbsp;<br> As what i understand, this clap switch can detect&nbsp;false&nbsp;triggering from claps where it <strong>protects your circuit from turning on and off due to&nbsp;unnecessary&nbsp;sounds or&nbsp;unintended&nbsp;sounds or claps</strong>.<br> Very nice clap circuit actually but needs some programming.<br> <br> I have a <strong>circuit </strong>here from my friend and very <strong>good for&nbsp;beginners&nbsp;like me</strong>, i guess. just see the diagram below if you are&nbsp;interested. &nbsp;If you are interested only.<br> <em>copied from:&nbsp;<a href="http://www.simple-electronics.com/2010/11/clap-activated-relay-or-switch-220v.html">http://www.simple-electronics.com/2010/11/clap-activated-relay-or-switch-220v.html</a></em><br> <br>
Isn't Patrick's Battery Operated circuit More Safer since He's Using A 9 Volt Battery???? Your Friend's Circuit uses 220/120 Vac which I believe is a little Dangerous for a Beginner!!! Until you get a little Experience in Electronics I would Suggest You stay with 9 Volts!!! If you still want to Dabble with Line Powered Projects get yourself a Variac/Isolation Transformer So that You can Test Your Line Powered circuit at lower ac voltage Levels,,,safety First!!!! A Variac is a Variable Ac Voltage Transformer while a Isolation Transformer Can Prevent Accidental Shocks If By Chance You Touch a Metal Chassis(Especially in Old Tube radios) It scares me half to DEATH why there are Instructables that have plans to restore tube radios WITHOUT the Use of a Variac/isolation tranformer. Remember 120/220 Vac will respect You if You respect it!!!
True, but markee2's have more possibilities to use it in practical sense. Ofcourse you have to know how to protect your self and circuit to make something like that with some level of protection, otherwise you are just like bookie.
would be glad if you send me the pic program for the circuit,email me at pdnashe@gmail.com
legit
Sir please Teelll mee The Apllication for this clap detector....???? please reply here fast......
I did it without software, using a 555 timer as a monostable multivibrator and a JK flip-flop. BUT I have a problem. <br>The out of the comparator is a VOLTAGE signal, and the 555 timer is activated with GROUND..... how am I supposed to connect this 2 circuits???? =S <br> <br>PLEASE HELP!
you need to switch the input to the lm324, between the voltage from the divider and the signal comming from the mic. (This is the comparation stage of the LM324, not the amplification stage) <br>May be this links can help you a little bit <br>http://en.wikipedia.org/wiki/Comparator <br>http://home.cogeco.ca/~rpaisley4/LM555.html
I did it with a different uController, thanks for your post, it helps me with the electret mic. <br>http://youtu.be/4OuOy0e1VSY
Hi. Just need to check...is there a missing resistor to the right of the dc blocking cap that connected to 5v since this is a single rail supply?
hi this project is somewhat similar to my project by i am using different microcontroller...is it ok if i ask for the codes??? please email me at dbuot63@yahoo.com. <br>thanks
hi im currently going to LTI and i want to do this for my final project. the only problem is our school can only program 8251 microcontrollers or chips like that. is there a chip that is equivalent to the one you used that i could get instead? please email me at dmfbaseball92@yahoo.com. <br> <br>Thank you.
Hello, I really like your circuit and code, but could you please tell me where in code can I increase the time interval for detecting second clap? I would like about 1s interval. Thanks
I am Karan Shrestha And I wnt to build it but I dont know how to use the software. I m reading in class 11. Please help me. My email is krrran000@gmail.com or brokenheart418@gmail.com <br>
Hi Patrick <br> <br>My name is Riyad, I am currently building a clap switch circuit that I found on the internet for University but it is a single clap switch and I would like to change it to a double clap the hardware way but I don't know hoe to do this. Can you help me please? I don't have much time left as it is due 3days time. My email is riyad.abrahams@gmail.com if you are able to email me I can show you what circuit I am using. <br> <br>Thanks a Million <br>Riyad
do you have the code for 16f628a
Where are you using the LM78L05 Mini 5v Regulator?<br><br><br>Can i do the circuit without this component?<br><br>I like the circuit you made. It is simple and very understandable.
Thanks! <br>If you look at the upper right hand side of the board, you will see a transistor and the regulator. They have the same package.
Thanks, a few days ago I did the circuit and it worked great! Thanks for all your help.
Sorry, I got it, you are using this in the power supply. <br>Anyways, why using the LM78L05 instead of using a resistor to resist 9v into 5v?<br><br>Can I do the circuit without this component ? Because I live in Argentina and it is hard to get this kind of things here.<br><br>Thanks for all, and sorry for my bad english.
Great circuit! I did this with an Arduino, but that's just an overkill..<br><br>Is it okay if I use a 5.7 volts power supply, and skip the voltage regulator? Or is it too much.<br><br>Also, how sensitive is this device? Will it work fine on a few meters range indoors without the need to clap like a mad man?
Hi <br>Thanks! I'd not change 5.7v. I'd use the regulator. However, a 7805 reguires about 6.5v-7v minimum to regulate properly to 5v. <br> <br>I just completed a better version of this circuit that does not require an amplifier. <br> <br>The sensitivity of this circuit is cased on your amplifiers. You can adjust them for your required sensitivity. <br> <br>
can this be done with a ir reciever and transmitter?
What is the purpose of the 5V pullup on the electret? Is the DC biasing really necessary?
It is extremely necessary. You are protecting the microphone through current limitation. The resistance of the microphone is about 1k ohms when there is no noise being detected. I have never seen a microphone circuit that has a mic connected directly to the power line. <br><br>I don't think you'd see much at the secondary end of the coupling capacitor if you placed the microphone between5v and ground, with the coup0ling capacitor connected to the power line as well.

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Bio: Hi there! My name is Patrick, and I am an electronics engineering technician who works full time as a lab tech, and part time as ... More »
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