DC SPEED CONTROLLERS

7/30/2019 DC SPEED CONTROLLERS

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DC SPEED CONTROLLERS

This handy circuit can be used as a speed controller for a 12V motor rated up to 5A

(continuous) or as a dimmer for a 12V halogen or standard incandescent lamp rated up to

50W. It varies the power to the load (motor or lamp) using pulse width modulation (PWM) at

a pulse frequency of around 220Hz.

SILICON CHIPhas produced a number of DC speed controllers over the years, the most

recent being our high-power 24V 40A design featured in the March & April 2008 issues.

Another very popular design is our 12V/24V 20A design featured in the June 1997 issue and

we have also featured a number of reversible 12V designs.

Circuit looks like:

For many applications though, most of these designs are over-kill and a much simpler circuit

will suffice. Which is why we are presenting this basic design which uses a 7555 timer IC, a

Mosfet and not much else. Being a simple design, it does not monitor motor back-EMF to

provide improved speed regulation and nor does it have any fancy overload protection apartfrom a fuse. However, it is a very efficient circuit and the kit cost is quite low.

Parts layout:
http://www.siliconchip.com.au/http://www.siliconchip.com.au/http://lh3.ggpht.com/-dqxch9DzetU/TfKMd8gxZcI/AAAAAAAACmk/OZWuNRfc6z4/s1600-h/12V-speed-controller-lamp-dimmer-circuit%255B6%255D.jpghttp://www.siliconchip.com.au/


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Connection diagram:

There are many applications for this circuit which will all be based on 12V motors, fans or

lamps. You can use it in cars, boats, and recreational vehicles, in model boats and model

railways and so on. Want to control a 12V fan in a car, caravan or computer? This circuit will

do it for you.

Circuit diagram:
http://lh5.ggpht.com/-9yKk0NLp0_w/TfKMlldEVCI/AAAAAAAACm8/TOhZt55y96Y/s1600-h/12V-speed-controller-lamp-dimmer-circuit-diagram%255B5%255D.jpghttp://lh5.ggpht.com/-MYdAFCFsYlA/TfKMi_7T5oI/AAAAAAAACm0/OyDJYZ6XFnE/s1600-h/12V-motor-speed-controller-lamp-dimmer-circuit%255B7%255D.jpghttp://lh6.ggpht.com/-_LCKaqNnW8U/TfKMg4uQHbI/AAAAAAAACms/_jYFdWgjArE/s1600-h/parts-layout-12V-speed-controller-lamp-dimmer-circuit%255B6%255D.jpghttp://lh5.ggpht.com/-9yKk0NLp0_w/TfKMlldEVCI/AAAAAAAACm8/TOhZt55y96Y/s1600-h/12V-speed-controller-lamp-dimmer-circuit-diagram%255B5%255D.jpghttp://lh5.ggpht.com/-MYdAFCFsYlA/TfKMi_7T5oI/AAAAAAAACm0/OyDJYZ6XFnE/s1600-h/12V-motor-speed-controller-lamp-dimmer-circuit%255B7%255D.jpghttp://lh6.ggpht.com/-_LCKaqNnW8U/TfKMg4uQHbI/AAAAAAAACms/_jYFdWgjArE/s1600-h/parts-layout-12V-speed-controller-lamp-dimmer-circuit%255B6%255D.jpghttp://lh5.ggpht.com/-9yKk0NLp0_w/TfKMlldEVCI/AAAAAAAACm8/TOhZt55y96Y/s1600-h/12V-speed-controller-lamp-dimmer-circuit-diagram%255B5%255D.jpghttp://lh5.ggpht.com/-MYdAFCFsYlA/TfKMi_7T5oI/AAAAAAAACm0/OyDJYZ6XFnE/s1600-h/12V-motor-speed-controller-lamp-dimmer-circuit%255B7%255D.jpghttp://lh6.ggpht.com/-_LCKaqNnW8U/TfKMg4uQHbI/AAAAAAAACms/_jYFdWgjArE/s1600-h/parts-layout-12V-speed-controller-lamp-dimmer-circuit%255B6%255D.jpg


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The circuit uses a 7555 timer (IC1) to generate variable width pulses at about 210Hz. This

drives Mosfet Q3 (via transistors Q1 & Q2) to control the speed of a motor or to dim an

incandescent lamp.

Halogen lamps:

While the circuit can dim 12V halogen lamps, we should point out that dimming halogen

lamps is very wasteful. In situations where you need dimmable 12V lamps, you will be muchbetter off substituting 12V LED lamps which are now readily available in standard bayonet,

miniature Edison screw (MES) and MR16 halogen bases. Not only are these LED

replacement lamps much more efficient than halogen lamps, they do not get anywhere near as

hot and will also last a great deal longer.

LINE FOLLOWER ROBOT SCANNER

This Line Following Robot sensor or surface scanner for robots is a very simple, stamp-sized,

short range (5-10mm) Infrared proximity detector wired around a standard reflective opto-

sensor CNY70(IC1). In some disciplines, a line following robot or an electronic toy vehicle

go along a predrawn black line on a white surface. In such devices, a surface scanner, pointed

at the surface is used to align the right track.

IC1 contains an infrared LED and a phototransistor. The LED emit invisible infrared light on

the track and the phototransistor works as a receiver. Usually, black colored surface reflects

less light than white surface and more current will flow through the phototransistor when it is

above a white surface. When a reflection is detected (IR light falls on the phototransistor) a

current flows through R2 to ground which generates a voltage drop at the base of T1 to make

it conduct. As a result, transistor T2 start conducting and the visual indicator LED(D1) lights

up. Capacitor C2 works as a mini buffer.

Line Follower Robot Scanner Schematic

After construction and installation, the scanner needs to be calibrated. Initially set P1 to its

mechanical centre position and place the robot above the white portion of the track. Now

slowly turn P1 to get a good response from D1. After this, fine tune P1 to reduce false


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detection caused by external light sources. Also ensure that the LED remains in off condition

when the sensor module is on the blackarea. Repeat the process until the correct calibration is

achieved.

The red color LED (D1) is only a visual indicator. You can add a suitable (5V) reed relay inparallel with D1-R4 wiring after suitable alterations to brake/stop/redirect the robot.

Similarly, the High to low (H-L) transition at the collector of T2 can be used as a signal to

control the logic blocks of the robot. Resistor R1 determines the operating current of the

IRLED inside IC1. The sensing ability largely depends on the reflective properties of the

markings on the track and the strength of the light output from IC1.

IRDA INTERFACE CIRCUIT DIAGRAM

Many modern motherboards are equipped with an infrared data interface compliant with the

IrDA standard, but this interface not very often used. However, it is not difficult to build a

data transmission module and connect it to the corresponding header. As can readily be seen

from the schematic diagram, this doesnt exactly involve a large array of ICs. This is because

transceiver ICs are available for the IrDA standard, so only a few passive components have to

be added to obtain an operational circuit. The author has successfully built this circuit many

times using the TFDU5102 from Vishay Semiconductors (formerly Telefunken). If this IrDA

transceiver is no longer available (it has been officially discontinued), the largely pin- and

function-compatible TFDU6102 can be used without any problems.

Circuit diagram :
http://www.ecircuitslab.com/http://www.ecircuitslab.com/


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IrDA Interface Circuit

Diagram

This IC is faster and meets the latest IrDA specification. The TFDU6102 low-power receiver

IC supports IrDA at data rates up to 4 Mbit/s (FIR), HP-SIR, Sharp ASK, and carrier-based

remote control modes up to 2 MHz. The IC contains a photodiode, an infrared emitter and

CMOS control logic. The IC also has internal protection against electromagnetic immissions

and emissions, so no external screening is necessary. The IC works with a supply voltage of

2.75.5 V, so it is suitable for use in desktop PCs, notebooks, palmtops, and PDAs. It is also

used in digital still and video cameras, printers, fax machines, copiers, projectors, and many

other types of equipment.

PCB Layout

Parts PCB Layout IrDA Interface Circuit

Diagram

Parts:

Resistors:R1 = 75 (shape 1210)R2 = 47 (shape 1206)
http://www.ecircuitslab.com/http://www.ecircuitslab.com/http://www.ecircuitslab.com/http://www.ecircuitslab.com/http://www.ecircuitslab.com/http://www.ecircuitslab.com/http://www.ecircuitslab.com/http://lh5.ggpht.com/-lhnm7VaWIhc/Tf85txXWWyI/AAAAAAAACwI/u1pO20vLYxc/s1600-h/Parts_PCB_Layout_IrDA_Interface_Circuit_Diagram1%255B6%255D.gifhttp://lh4.ggpht.com/-3h1m8t3Xklk/Tf85poimIoI/AAAAAAAACwA/pcZkC7nrzls/s1600-h/IrDA_Interface_Circuit_Diagram%25201%255B6%255D.gifhttp://lh5.ggpht.com/-lhnm7VaWIhc/Tf85txXWWyI/AAAAAAAACwI/u1pO20vLYxc/s1600-h/Parts_PCB_Layout_IrDA_Interface_Circuit_Diagram1%255B6%255D.gifhttp://lh4.ggpht.com/-3h1m8t3Xklk/Tf85poimIoI/AAAAAAAACwA/pcZkC7nrzls/s1600-h/IrDA_Interface_Circuit_Diagram%25201%255B6%255D.gifhttp://www.ecircuitslab.com/http://www.ecircuitslab.com/http://www.ecircuitslab.com/http://www.ecircuitslab.com/


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R3 = 100 k (shape 1206)

Capacitors:

C1 = 100nF (shape 1206)

C2 = 4F7 (shape 1210)

Semiconductors:

IC1 = TFDU6102TR3 (Vishay) (Farnell)Miscellaneous:X1 = 5-way SIL pinheader

The author has designed a printed circuit board for the IrDA module that is only 20 20 mm

square. Of course, this means that all of the components are SMD types. The TFDU6102 in

the babyface package is available in upright and flat versions. Here the upright version

(suffix TR3) is used. Thanks to its small size, the assembled circuit board can easily be

placed behind a drive bay cover or the like. It is connected to the motherboard by a five-way

flat cable. The pin assignments for header X1 must match the mating connector on the

motherboard. After you have fitted the module, you may have to edit the BIOS settings to

activate the UART for IrDA operation. These settings enable the (Windows) operatingsystem to boot the new device and automatically install it. You may have to briefly insert the

Windows CD to modify the settings. There is an abundance of free programs on the Internet

that use the IrDA interface.

A portable USB hard drive is a great way to back up data but what if your USB ports are

unable to supply enough "juice" to power the drive? A modified version of theSilicon Chip

Usb Power Injectoris the answer. For some time now, the author has used a portable USB

hard drive to back up data at work. As with most such drives, it is powered directly from the

USB port, so it doesnt require an external plug pack supply.

Project's Picture:
http://www.siliconchip.com.au/cms/A_110648/article.htmlhttp://www.siliconchip.com.au/cms/A_110648/article.htmlhttp://www.siliconchip.com.au/cms/A_110648/article.htmlhttp://www.siliconchip.com.au/cms/A_110648/article.htmlhttp://lh4.ggpht.com/-C-jhH5S3U3g/Tj2DP1Yv0aI/AAAAAAAADMA/V_jVvXKJrIU/s1600-h/finished-projects%255B7%255D.jpghttp://www.siliconchip.com.au/cms/A_110648/article.htmlhttp://www.siliconchip.com.au/cms/A_110648/article.html


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In fact, the device is powered from two USB ports, since one port is incapable of supplying

sufficient current. Thats done using a special USB cable thats supplied with the drive. It has

two connectors fitted to one end, forming what is basically a "Y" configuration (see photo).

One connector is wired for both power and data while the other connector has just the power

supply connections. In use, the two connectors are plugged into adjacent USB ports, so that

power for the drive is simultaneously sourced from both ports.

USB Cable:

An external USB hard drive is usually powered by plugging two connectors at one end of aspecial USB cable into adjacent USB ports on the computer. This allows power to be sourced

from both ports. According to the USB specification, USB ports are rated to supply up to

500mA at 5V DC, so two connected in parallel should be quite capable of powering a

portable USB hard driveat least in theory.

Complete Project:
http://lh4.ggpht.com/-ngwdHfg4708/Tj2DTDhGhxI/AAAAAAAADMI/GBuSSEN0G2g/s1600-h/usb-cables%255B6%255D.jpg


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Unfortunately, in my case, it didnt quite work out that way. Although the USB drive worked

fine with several work computers, it was a "no-go" on my home machine. Instead, when it

was plugged into the front-panel USB ports, the drive repeatedly emitted a distinctive

chirping sound as it unsuccessfully tried to spin up. During this process, Windows XP did

recognise that a device hadbeen plugged in but thats as far as it went it couldnt identify

the device and certainly didnt recognize the drive. Plugging the drive into the rear-panel

ports gave exactly the same result. The problem wasnt just confined to this particular drive

either. A newly-acquired Maxtor OneTouch4 Mini drive also failed to power up correctly on

my home computer, despite working perfectly on several work computers.

Circuit diagram:

The revised USB Power Injector is essentially a switch and a 5V regulator. The Vbus supply

from USB socket CON1 turns on transistor Q1 which then turns on power Mosfet Q2. This

then feeds a 6V DC regulated supply from an external plug pack to regulator REG1 which in

turn supplies 5V to USB socket CON2.
http://lh4.ggpht.com/-coJ7aDY-ErE/Tj2DZVPpTsI/AAAAAAAADMY/gvG_vhwXemM/s1600-h/circuit%2520diagram%255B7%255D.jpghttp://lh5.ggpht.com/-lARH7nuUkBo/Tj2DWFg3bOI/AAAAAAAADMQ/c3GVVCVddQ8/s1600-h/Complate%2520project-in-box%255B6%255D.jpghttp://lh4.ggpht.com/-coJ7aDY-ErE/Tj2DZVPpTsI/AAAAAAAADMY/gvG_vhwXemM/s1600-h/circuit%2520diagram%255B7%255D.jpghttp://lh5.ggpht.com/-lARH7nuUkBo/Tj2DWFg3bOI/AAAAAAAADMQ/c3GVVCVddQ8/s1600-h/Complate%2520project-in-box%255B6%255D.jpg


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Bass Boost is today's sound... whether it's the driving, gut-vibration pulsation of disco, or the

solid bass line of soft, hard, or laid-back rock. One way to get the modern bass-boost sound

without running out and buying an all-new expensive piece of equipment is to use a Bass

Booster between your guitar, electronic organ or what-have-you, and the instrument

amplifier. A bass booster strips the highs from the instrument's output signal and amplifies

low frequencies, feeding on "all-bass" sound to the instrument amplifier. Naturally, thebigger the speaker used with the amp, the more powerful the bass: use 15-inchers with the

Bass Booster and you can rattle the windows. Bass Booster is powered by an ordinary 9 volt

transistor radio battery. It can be assembled on a small printed board or on a veroboard using

point to point wiring. The booster connects between your instrument and its amplifier through

two standard RCA Jacks.

Circuit Diagram:

Bass Booster Circuit

Diagram

Parts:

P1 = 50K

P2 = 100K

R1 = 22K

R2 = 470K

R3 = 47K

R4 = 10K

R5 = 470R

R6 = 1K

Q1 = 2N2222C1 = 2.2uF-25v

C2 = 100nF-63v

C31 = 00nF-63V

C4 = 3.3uF-25v

C5 = 470uF-25v

D1 = 5mm. Red Led

Q1 = 2N2222

B1 = 9v Battery

J1 = RCA Audio Input Socket

J2 = RCA Audio Output Socket

S1 = On-Off Switch
http://www.ecircuitslab.com/http://www.ecircuitslab.com/http://www.ecircuitslab.com/http://lh6.ggpht.com/-w9zhDfMALLE/TfTocymuZRI/AAAAAAAACoU/NEM8tiUr27g/s1600-h/Bass%2520Booster%2520Circuit%255B6%255D.gifhttp://www.ecircuitslab.com/http://www.ecircuitslab.com/


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Using Bass Booster:

Connect your electronic guitar or other electronic instrument to input jack J1; Connect output

jack J2 to your instruments amplifier's normally-used input. With power switch S1 off, key

S2 so the instrument feeds directly to the instrument amplifier. With P2 set full counter-

clockwise (Off), turn power switch S1 on, key S2 once, and advance P2 for the desired BassBoost level. To cut back to natural sound just stomp down on S2 and key the Bass Booster

out. Don't worry about leaving power switch S1 on for several hours of a gig. The circuit

pulls less than 1mA from the battery, so battery will last many, many months.

555 Timing for a stepper motor

Posted by ganesh at 11:03 AM

Monday, December 22, 2008

In the circuit a 555 drives a UCN 5804 stepper motor chip. My problem is with the speed

switch set to slow the motor is driven too slow, and with the switch set to fast the motor is

driven too fast.I have changed the pot to 1M but the slowest speed (with the switch set to fast) is the fastest
http://ganesh-circuit.blogspot.in/2008/12/555-timing-for-stepper-motor.htmlhttp://ganesh-circuit.blogspot.in/2008/12/555-timing-for-stepper-motor.htmlhttp://www.adbrite.com/mb/commerce/purchase_form.php?opid=1007288&afsid=1http://www.adbrite.com/mb/commerce/purchase_form.php?opid=1007288&afsid=1http://www.adbrite.com/mb/commerce/purchase_form.php?opid=1007288&afsid=1http://ganesh-circuit.blogspot.in/2008/12/555-timing-for-stepper-motor.html


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speed I require. At the slowest speed I would like to pulse the motor every 1-2 seconds.

I understand that the capacitor and resistors adjust the timing, but I dont understand the

relationship between them.

Could somebody help me with this?

Super simple stepper motor controller

Posted by ganesh at 8:56 PM

Friday, December 19, 2008

The circuit shown above can be used to control a unipolar stepper motor which has FOUR

coils (I've swiped it off an old fax machine). The above circuit can be for a motor current of

up to about 500mA per winding with suitable heat sinks for the SL100. For highercurrents

power transistors like 2N3055 can be used as darlington pair along with SL100. The diodesare used to protect the transistor from transients.Activating sequence:-
http://ganesh-circuit.blogspot.in/2008/12/super-simple-stepper-motor-controller.htmlhttp://ganesh-circuit.blogspot.in/2008/12/super-simple-stepper-motor-controller.htmlhttp://1.bp.blogspot.com/_ibJNjLB4Qfg/SUx7a_zfmqI/AAAAAAAAABE/eN3TWMoAKPU/s1600-h/STEPPER.gifhttp://www.adbrite.com/mb/commerce/purchase_form.php?opid=1007288&afsid=1http://1.bp.blogspot.com/_ibJNjLB4Qfg/SUx7a_zfmqI/AAAAAAAAABE/eN3TWMoAKPU/s1600-h/STEPPER.gifhttp://www.adbrite.com/mb/commerce/purchase_form.php?opid=1007288&afsid=1http://1.bp.blogspot.com/_ibJNjLB4Qfg/SUx7a_zfmqI/AAAAAAAAABE/eN3TWMoAKPU/s1600-h/STEPPER.gifhttp://www.adbrite.com/mb/commerce/purchase_form.php?opid=1007288&afsid=1http://ganesh-circuit.blogspot.in/2008/12/super-simple-stepper-motor-controller.html


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Inputs

Coils Energised

D0

D1

00

A,B

0

1

B,C

1

0

C,D

1

1

D,ATo reverse the motor just reverse the above sequence viz. 11,10,01,00.

Alternately a 2bit UP/DOWN counter can also be used to control the direction , and a 555

multi-vibrator can be used to control the speed

DC SPEED CONTROLLERS

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