Super simple stepper motor controller

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 higher currents power transistors like 2N3055 can be used as darlington pair along with SL100. The diodes are used to protect the transistor from transients.Activating sequence:-Inputs D0 D1 Coils Energised0 0 A,B0 1 B,C1 0 C,D1 1 D,ATo reverse the motor just reverse the above sequence viz. 11,10,01,00.Alternately...

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Discrete component motor direction controller

This circuit can control a small DC motor, like the one in a tape recorder. When both the points A & B are "HIGH" Q1 and Q2 are in saturation. Hence the bases of Q3 to Q6 are grounded. Hence Q3,Q5 are OFF and Q4,Q6 are ON . The voltages at both the motor terminals is the same and hence the motor is OFF. Similarly when both A and B are "LOW" the motor is OFF. When A is HIGH and B is LOW, Q1 saturates ,Q2 is OFF. The bases of Q3 and Q4 are grounded and that of Q4 and Q5 are HIGH. Hence Q4 and Q5 conduct making the right terminal of the motor more positive than the left and the motor is ON. When A is LOW and B is HIGH ,the left terminal...

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Automatic Speed Controller for fans & Coolers

During summer nights, the temperature is initially quite high. As time passes, the temperature starts dropping. Also, after a person falls asleep, the metabolic rate of ones body decreases. Thus, initially the fan/cooler needs to be run at full speed. As time passes, one has to get up again and again to adjust the speed of the fan or the cooler.The device presented here makes the fan run at full speed for a predetermined time. The speed is decreased to medium after some time, and to slow later on. After a period of about eight hours, the fan/cooler is switched off.Fig. 1 shows the circuit diagram of the system. IC1 (555) is used as an astable...

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Compiler Hex code file to be directly programmed into the PIC

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Parts list:

Parts list:ICs:IC1- PIC16F84A microcontrollerIC2- MCT2E opto isolatorIC3- NE555 timer IcIC5- 7805C or 7805CT regulator ICResistors (all 1/4th W unless otherwise stated):R1- 10K, 1WR2- 15KR3 to R6 - 2.2KR7 - 2.2K (eight pieces for eight relay circuits)Capacitors:C1- 0.47uF/200V non electrolyticC2- 47uF/25V electrolyticC3,C4 - 22pF non electrolyticC5- 0.01uF non electrolyticC7,C8 - 0.1 uF non electrolyticC9,C10- 100uF/25V electrolyticTransistors:BC547 - eight piecesRelays:12V, 60mA (or less) relay with 2A SPDT switching contacts - 8 piecesDIP switch:4 switch DIPDiodes:D1,D2 - 10V, 500mW zener diodesD3 - 1N4007D4 - 1N4007 (8 pieces for 8 relay circuits)Crystal:Q1 - 4MHz ceramic crystal resona...

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C source code complied using HT-Soft PIC C compiler

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99;...

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Circuit : Telephone operated remote control using PIC16F84A microcontroller

Circuit : Telephone operated remote control using PIC16F84A microcontrol...

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Telephone operated remote control using PIC16F84A microcontroller

This design controls up to 8 devices using a PIC microcontroller (PIC16F84A) connected to the phone line. The unique feature here is that unlike other telephone line based remote control, this device does not need the call to be answered at the remote end so the call will not be charged. This device depends on number of rings given on the telephone line to activate/deactivate devices. Circuit diagram (designed by www.tronicszone.com)Parts ...

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Dew sensor

Dew (condensed moisture) ad- versely affects the normal per- formance of sensitive electronic devices. A low-cost circuit described here can be used to switch off any gadget automatically in case of excessive humidity. At the heart of the circuit is an inexpensive (resistor type) dew sensor element.Although dew sensor elements are widely used in video cassette players and recorders, these may not be easily available in local market. However, the same can be procured from authorised service centres of reputed companies. The author used the dew sensor for FUNAI VCP model No. V.I.P. 3000A (Part No: 6808-08-04, reference no. 336) in his prototype.In...

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Magnetic proximity sensors

Here is an interesting circuit for a magnetic proximity switch which can be used in various applications.The magnetic proximity switch circuit, in principle, consists of a reed switch at its heart. When a magnet is brought in the vicinity of the sensor (reed switch), it operates and controls the rest of the switching circuit. In place of the reed switch, one may, as well, use a general-purpose electromagnetic reed relay (by making use of the reed switch contacts) as the sensor, if required. These tiny reed relays are easily available as they are widely used in telecom products. The reed switch or relay to be used with this circuit should...

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Chapter 3: Inductor

Let me be very brief here. The main purpose of this tutorial is to explain what an inductor is and how it behaves in an electronic circuit. The definition of inductance goes like this: "Inductance is the ability of a coil to establish (or induce) a voltage within itself to oppose changes in current through its windings". That means when varying current flows through a coil, a voltage is induced within the coil in a direction so as to oppose the change of current through it. The circuit symbol of an inductor is: and like a resistor, it can be connected either way in a circuit, with the exception of mutually coupled coils that...

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Chapter 2: Capacitor

Capacitors in electronics are like storage tanks. They store charges. Basically a capacitor is made up of 2 parallel plates separated by a very small gap, but there are other ways of making a capacitor too. A capacitor has two terminals. It is charged by applying a voltage across its terminals, and discharged by shorting the two terminals. When a capacitor is charged, a voltage develops across its terminals even when the charging source is removed. The voltage across the terminals of a capacitor is related to the amount of charge stored in it by the relation: Voltage = Charge/Capacitance or V = Q / C Where C is the capacitance...

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