The Dalf Motor Control Board was designed as a companion to a pair ofOSMC Motor Drivers to control a pair of brushed PM DC motors, however it is usable with other motor drivers that use signed magnitude PWM controls. It also makes a wonderful development board for other applications because of the abundant IO and the use of standard software tools. The built-in firmware provides several different open and closed loop motor control methods. For closed loop applications it uses standard quadrature feedback from incremental encoders. Optionally, for suitable applications, analog position feedback may replace the optical encoders. Based on the PIC18F6722 running at 40MHz (10 MIPS), the hardware and firmware provide multiple user interfaces including: 3 channel RC with either tank or mixed modes, analog controls (center off or full range) using off board potentiometers, and serial command interfaces using the serial RS232 and I2C Busses. Closed loop PID using a Trapezoidal Generator is provided for both positional, and velocity controls. Adjustable slew rate is one of many features supported using non volatile storage for motor parameters. Voltage windows implemented using comparator circuitry and digitally adjustable pots provide very fast current limiting response when used with off board current sensors. Features are easily extensible using standard Microchip software tools, the supplied files (main.c + dalf.lib), and the 6-pin modular connector which is suitable for direct plug from the Microchip ICD2 Product. A Boot loader supports firmware upgrades over the serial link. Lots of unused I/O with signals accessible from the screw terminals and ribbon connectors. Ample headroom for additional code development in both FLASH and RAM memory. The +5V power supply supports a robust BEC for off board usage. Two I2C busses and two RS232 ports are routed to connectors. Detailed documentation including a voluminous Owner's Manual describing all features, and a somewhat less imposing, Getting Started Manual, are available for download.

Differential Robot Base

12V geared PMDC wheelchair motors paired with US Digital incremental encoders (CPR=64) provide quadrature signals for position and velocity control.

Also shown are two OSMC Motor Drivers with cooling fans. The motors are over-driven with an 18V supply for a maximum RPM of about 360. Not shown is an additional 3.6:1, belt driven, gear reduction assembly that drives the 10" wheels.

The Dalf Motor Controller and OSMC Motor Drivers are available.

Experimenters Breadboard

A couple of motor/encoder combos (CPR=20), a dual motor driver, an R/C receiver, and a small breadboard for LED's, switches, pots, or whatever. The receiver antennae is shown in the background wrapped around a pencil (very professional!).

When driven with +12V the motors have a maximum RPM of about 4,000. The motor/encoder combo units (also gear reduction assemblies) available.

Music Dancing LEDs

If you are a music lover then you can enhance your music experience by making a Music Dancing LEDs project all by yourself if you have a little bit knowledge about electronics.

The circuit comprises of 3 different bands Red,Green and Blue for high,medium and low frequencies respectively. It is a simple circuit which you can assemble on a bread board easily by following the given circuit diagram and buying the respective components for it. I have tested this circuit by myself by assembling it on a vero board so it is 100% working

you can detect earthquake with your phone?

Almost all smartphone users know that all smartphones now a days are coming with a lot of sensors in them. Even the most cheap android smartphone has Accelerometer which is used for Auto-rotate. I was surfing the web news and found a really great tool which can graph the movement of your phone or tablet.

Then I read a post which says that you can use your phone as a basic seismometer. Don’t expect professional level results from your phone. So let’s get to it.

How to use your phone as earthquake detector.

Here is a web-page which is written is simple java-script and works on every modern day smartphone. Just open the link and it will start making a graph of the movement of your phone. Ofcourse you can manipulate the output by shaking your phone. Even if I open the link in my laptop, Which doesn’t have any accelerometer in it, The graph is moving a little.

So, If you thought that you can actually use your phone as a professional seismometer, you are a genius. This is what I am going to show you now. Just open the link given above, and place your phone on a flat surface like a table or ground.

If you see a lot of movement in the graph, either the earth is shaking or your phone’s sensor is faulty. 

I will again mention that you should not use it as a reliable seismometer. But there is something which is better then nothing.

Infrared Security Alarm

Wondering if you can setup a small and cheap alarm system for your home? Then you are at the right place because I present to you an infrared security alarm system that you can create at your home yourself easily by spending some small amount of money and making up a simple circuit if you have good enough knowledge about electronics.

An infrared security alarm system is based on the detection of an intrusion caused by the interruption of an infra-red (which is invisible to human being) light beam being emitted by an infra-red LED and falling on a matched IR sensor. Both the transmitter and the receiver portions separately operate on 6v supplies. The transmitter and the receiver’s circuits can be mounted in an aligned position on the two sides of a door to check intrusion or even on the two facing walls of inside of a locker to give you an alarm whenever an unauthorized person attempts a mischief. The circuit has a provision of both audio as well as visible indications. The audio indicator and the visible indication can be remotely located away from the location of gadget also. The IR based system is very much advanced and works very much accurately. This type of devices are designed and marketed by the different multinational companies.

I have tested this circuit by myself on a vero board and it works 100% accurately.

Components Required:

1. Power Supplies:
   • 2x 220V-9V (or more) Step Down Transformer
   • 2x Bridge Rectifier
   • 2x 7806 IC
   • 2x 3300uF Capacitor
   • 2x 10uF Capacitor
   • 2x Heat Sink
2. Transmitter Section:
   • 1N4148 Diode
   • 1 Kohm resistor
   • 22 ohm resistor (0.5W)
   • 2.2 Kohm resistor
   • 2x 0.01 uF capacitor
   • Pot 4.7 Kohm variable resistor
   • BC547 Transistor
   • 555 IC
   • Infrared LED
3. Receiver Section:
   • TSOP 1738 IR Receiver
   • 2x 220 ohm resistor
   • 1.8 Kohm resistor
   • 2x 4.7 Kohm resistor
   • 2x 1 Kohm resistor
   • 1 Mohm resistor
   • 470 ohm resistor
   • 220 Kohm resistor
   • 4.7 ohm resistor (0.5W)
   • 47 uF capacitor (16V)
   • 2x 0.1 uF capacitor
   • 10 uF capacitor (16V)
   • 100 uF capacitor (16V)
   • 2x BC547 transistor
   • BC558 transistor
   • 3.3V zener diode
   • 1N4007 diode
   • LED green +red
   • Speaker 8ohm (1W)
   • CD4538 IC
   • UM3561 IC

Circuit Diagram:

Power Supply:

Transmitter:

Receiver:

Working:

In the transmitter circuit,we have taken IR because IR is invisible to the eye, where as in case of LASER, which is easily visible to the human eye by which will, alert the unauthorized person. That is why we have taken IR as a transmitter which will transmit a continuous IR signal. The 555 timer generates a 38KHz frequency which is then sensed by the TSOP1738 in receiver circuit.

The transmitted IR signal directly falls on IR sensor TSOP1738. Whenever the IR signal is interrupted, its output pin 3 goes low and IC2 is triggered at pin 5 through transistor T2. As a result, its output at pin 7 goes low (for a preset time) to forward bias siren-driver transistor T2. This condition is indicated by the glowing of LED1. The time-out period can be increased or decreased by changing the value of capacitor C6.

The output tone of siren-sound generator IC3 can be set by connecting its pin 6 to either Vcc or GND. When you connect pin 6 to Vcc IC3 produces the sound of fire-alarm siren, but when you connect it to GND it produces the sound of ambulance siren.

Notes:

• Both circuits have to be powered by different 6v power supplies.
• You may see and check the infrared led is glowing or not by using a camera.
• Receiver circuit may not properly sense the infrared led on a breadboard as it didnt work for me, so its better to assemble the circuit on a vero board or PCB.
• Heat sinks should be used with the 7806 ICs or the IC may get damaged if the circuit is powered on for a long time.
• Alarm turns off after about 5-10 seconds of getting the contact with IR again.
• Range of the circuit is about 5m.
• Vary the variable resistor to increase or decrease the intensity of the IR LED for better performance in lighting conditions.

Enclose your infrared security alarm system in different plastic or metal packaging and install it on adjacent walls of ur door and your home will be in protection.

Light Activated Switch

Make a light activated switch circuit which can be used for switching OFF a particular lamp or group of lamps in response to the varying ambient light levels. The project once built can be used for switching OFF a lamp when dawn breaks and switching it ON when dusk sets in. It can also be used as a night lamp which will turn on automatically at sleeping time when the room is dark.It is the most simple and cheap project for hobby purposes.

This circuit is tested by myself and it is 100% in working condition.

Components Required:

1. 9V Battery
2. LDR (Light Dependent Resistor)
3. Pot 47 Kohm variable resistor
4. 4 Kohm resistor
5. 10 Kohm resistor
6. 1 Kohm resistor
7. 2x 220 ohm resistor
8. LM311 IC
9. BC 107 transistor
10. LED (any color)
11. 1N4007 Diode
12. 12V SPST Relay

Circuit Diagram:

Working:

The circuit is based on National Semiconductors comparator LM311 (IC1) and an LDR. The non inverting input of IC1 is given with a reference voltage of 6V using resistors R3 and R4. The input to the inverting input will be the voltage across the LDR that is light dependent. At darkness the resistance of the LDR will be high and so do the voltage across it. In this condition the voltage at the inverting input will be higher than the reference at non inverting pin and the output of the comparator will be low. When the LDR is illuminated, its resistance drops and so does the voltage across it. Now the voltage at the inverting input will be lower than that at non inverting input and the out put of the comparator goes high. This makes transistor Q1 on and drives the relay. As a result we get a relay switching according to the intensity of the light falling on the LDR.

Notes:

• Adjust POT R1 to set the desired light intensity for switching the relay.For this illuminate the LDR with the desire intensity light.The relay will be either on or off. Adjust POT R1 slowly so that the state of the relay changes.That’s it. Now the circuit is set for the given intensity of light.
• Assemble the circuit on a good quality PCB or common vero board.
• You can use either a 9 V battery or a well regulated & filtered 9V DC mains operated power supply.
• The pin 5&6 (Balance & Balance/Strobe ) of IC LM311 are shorted to minimize the chance of oscillations.
• The pin out of LM311 is also given together with the circuit diagram.

Place your light activated switch circuit inside some small container/box and make sure the LDR is facing outside the box to detect light properly. This circuit is also used in street lights to turn on the lights automatically when it is dark.

Automatic Emergency Light

Nowadays, an automatic emergency light is a very important tool in our daily lives. An automatic emergency light is a battery-backed lighting device that turns on automatically when we experience a power outage. Emergency lights are standard in new commercial and high occupancy residential buildings, such as college dormitories. Most building codes require that they be installed in older buildings as well.

The circuit I am going to share is a fully automated circuit which turns off charging automatically when the battery is fully charged so you can keep it connected to your wall socket all day long without worrying about over charging issues.

Components Required:

1. NE555 IC
2. LM317 IC
3. Ferrite Transformer with 22 primary and 34 secondary turns
4. Center Taped Step down transformer 500mA 9V-0-9V
5. Tubelight 20W
6. 6V 4Ah Battery
7. SL100 Transistor (with heat sink)
8. 2N3055/MJE3055 Transistor (with heat sink)
9. 2x BC547 Transistor
10. 3x 1N4007 Diode
11. Zener diode 6.8V (0.5W)
12. 2x 0.01 uF Capacitor
13. 0.1 uF Capacitor
14. 6.8 uF Capacitor (25V)
15. Pot 1 Kohm Variable Resistor
16. 2x 1 Kohm Resistor
17. 2x 4.7 Kohm Resistor
18. 10 Kohm Resistor
19. 100 ohm Resistor
20. 150 ohm Resistor

Components Required:

1. NE555 IC
2. LM317 IC
3. Ferrite Transformer with 22 primary and 34 secondary turns
4. Center Taped Step down transformer 500mA 9V-0-9V
5. Tubelight 20W
6. 6V 4Ah Battery
7. SL100 Transistor (with heat sink)
8. 2N3055/MJE3055 Transistor (with heat sink)
9. 2x BC547 Transistor
10. 3x 1N4007 Diode
11. Zener diode 6.8V (0.5W)
12. 2x 0.01 uF Capacitor
13. 0.1 uF Capacitor
14. 6.8 uF Capacitor (25V)
15. Pot 1 Kohm Variable Resistor
16. 2x 1 Kohm Resistor
17. 2x 4.7 Kohm Resistor
18. 10 Kohm Resistor
19. 100 ohm Resistor
20. 150 ohm Resistor

Circuit Diagram:

The circuit can be divided into inverter and charger sections. The inverter section is built around timer NE555, while the charger section is built around 3-terminal adjustable regulator LM317. In the inverter section, NE555 is wired as an astable multivibrator that produces a 15kHz squarewave. Output pin 3 of IC 555 is connected to the Darlington pair formed by transistors SL100 (T1) and 2N3055 (T2) via resistor R4.

The Darlington pair drives ferrite transformer X1 to light up the tubelight. For fabricating inverter transformer X1, use two EE ferrite cores (of 25×13×8mm size each) along with plastic former. Wind 10 turns of 22 SWG on primary and 500 turns of 34 SWG wire on secondary using some insulation between the primary and secondary. To connect the tube-light to ferrite transformer X1, first short both terminals of each side of the tube-light and then connect to the secondary of X1. (You can also use a Darlington pair of transistors BC547 and 2N6292 for a 6W tube-light with the same transformer.)

Working:

When mains power is available, reset pin 4 of IC 555 is grounded via transistor T4. Thus, IC1 (NE555) does not produce square-wave and emergency light turns off in the presence of mains supply. When mains fails, transistor T4 does not conduct and reset pin 4 gets positive supply though resistor R3. IC1 starts producing square wave and tube-light turns on via ferrite transformer X1. In the charger section, input AC mains is stepped down by transformer X2 to deliver 9V-0-9V AC at 500mA. Diodes D1 and D2 rectify the output of the transformer. Capacitors C3 and C4 act as filters to eliminate ripples.

The unregulated DC voltage is fed to IC LM317 (IC2). By adjusting preset VR1, the output voltage can be adjusted to deliver the charging voltage. When the battery gets charged above 6.8V, zener diode ZD1 conducts and regulator IC2 stops delivering the charging voltage. Assemble the circuit on a general-purpose PCB and enclose in a cabinet with enough space for the battery and switches. Connect a 230V AC power plug to feed charging voltage to the battery and make a 20W tube outlet in the cabinet to switch on the tube-light.

Electronic Dice

You can make yourself an Electronic Dice that works just like a dice in a game giving random number whenever you press the button. It can be used in games and for children who dont know how to roll the dice or also for handicapped persons.

It is a simple and classic project for those getting interested in electronics. A timer, counter and a few LEDs makes a circuit that can also add a new twist to some old boring board games.

It is a tested and 100% working circuit.

Components Required:

1. NE555 IC
2. 4017B IC
3. 6x 1N4148 Diode
4. 7x Red LEDs
5. 4x BC109 Transistor
6. 7x 1 Kohm Resistor
7. 5x 10 Kohm Resistor
8. 2x 2.2 Kohm Resistor
9. 100 Kohm Resistor
10. 22 uF Capacitor
11. 0.01 uF Capacitor
12. Push Switch Button

Circuit Diagram:

Connect all the arrows on the transistors to the positive supply rail.

The LEDs Should Be Alligned As Following Image

Working:

The 555 timer IC is connected for Astable Operation, the clock pulses are fed to the 4017 IC via the 10K resistor. The 4017 is a 10 stage counter, output 6 (pin 5) is connected to RESET (pin 15), thus giving us a 6 stage counter , outputs 0 to 5.

6 of the LEDs are connected as 3 pairs, thus requiring 4 different signals, these signals come from the 4 transistors, which in turn are connected to the nescessary outputs of the 4017. Where a transistor is operated from more than one output, diodes are used to avoid a short circuit situation between outputs.

Pin 13 of the 4017 (INHIBIT) is connected to +ve via a 100K resistor to stop the counter from advancing, however pressing the ROLL button will connect pin 13 to -ve and allow the counter to advance, hence, throwing the dice.

LED Flasher Circuit

Today we are here with a very simple and cheap project for new comers to electronics field and for all hobbyist out there. This circuit is a LED flasher circuit that drives 48 white LEDs at once with a 12V battery and a 555 timer IC.

Note: The circuit is tested and 100% in working condition. Credit goes to Wajeeh Uddin of Hamdard University for providing us with images and testing the circuit.

LED Flasher Circuit

Components Required:

1.  12V Battery
2. On/Off Switch
3. 555 Timer IC
4. 10 uF or upto 100uF Capacitor
5. 33 Kohm resistance
6. 48 x White LEDs
7. 16 x 82 ohm Resistance

Circuit Diagram:

Working:

The 555 is capable of sinking and sourcing up to 200mA, but it gets very hot when doing this on a 12v supply. The following circuit shows the maximum number of white LEDs that can be realistically driven from a 555 and we have limited the total current to about 130mA as each LED is designed to pass about 17mA to 22mA maximum. A white LED drops a characteristic 3.2v to 3.6v and this means only 3 LEDs can be placed in series.

So if you are new in the field of electronics and want to learn making circuits or learning about the operation of 555 timer IC then this project is the most ideal and simplest project for you. You can even place this circuit in a suitable enclosure and put it up somewhere as a piece of decoration for house or even connect it into your car battery and place the LEDs inline if you like.

Digital Code Lock – DIY Project

A Digital Code Lock project is introduced in this article which is a really simple and low cost DIY project. There are many other digital code lock circuits available some use a certain set of switches to be pressed in a certain time and some use microprocessor or different ICs.

This circuit is a really simple circuit that uses NE555 timer IC and contains 10 switches to control the lock. Only 6 out of 10 switches are used in a particular sequence to open the lock.

Note: The circuit is tested by myself and in 100% working condition.

Components Required:

1. Center taped step down transformer 6V-0-6V
2. 4x 1N4001 Diode
3. 10x Push Button
4. NE555 IC
5. 6V Relay (100 ohm)
6. 1 uF Capacitor (16V)
7. 0.01 uF Capacitor
8. 5 uF Capacitor (16V)
9. 1000 uF Capacitor (16V)
10. LED red
11. 1 Mohm Resistor
12. 2x 10 Kohm Resistor
13. 1 Kohm Resistor
14. 820 ohm Resistor
15. Solenoid

Circuit Diagram:

Working:

Here the keying-in code is rather unique. Six switches are to be pressed to open the lock, but only two switches at a time. Thus a total of three sets of switches have to be pressed in a particular sequence. (Of these three sets, one set is repeated.)

An essential property of this electronic code lock is that it works in monostable mode, i.e. once triggered, the output becomes high and remains so for a period of time, governed by the timing components, before returing to the quiescent low state. In this circuit, timer IC 555 with 8 pins is used. The IC is inexpensive and easily available. Its pin 2 is the triggering input pin which, when held below 1/3 of the sup-ply voltage, drives the output to high state. The threshold pin 6, when held higher than 2/3 of the supply voltage, drives the output to low state. By applying a low-going pulse to the reset pin 4, the output at pin 3 can be brought to the quiescent low level. Thus the reset pin 4 should be held high for normal operation of the IC.

Three sets of switches SA-SC, S1-S8 and S3-S4 are pressed, in that order, to open the lock. On pressing the switches SA and SC simultaneously, capacitor C3 charges through the potential divider comprising resistors R3 and R4, and on releasing these two switches, capacitor C3 starts discharging through resistor R4. Capacitor C3 and resistor R4 are so selected that it takes about five seconds to fully discharge C3.

Depressing switches S1 and S8 in unison, within five seconds of releasing the switches SA and SC, pulls pin 2 to ground and IC 555 is triggered. The capacitor C1 starts charging through resistor R1. As a result, the output (pin 3) goes high for five seconds (i.e. the charging time T of the capacitor C1 to the threshold voltage, which is calculated by the relation T=1.1 R1 x C1 seconds).

Within these five seconds, switches SA and SC are to be pressed momentarily once again, followed by the depression of last code-switch pair S3-S4.

These switches connect the relay to out-put pin 3 and the relay is energised. The contacts of the relay close and the solenoid pulls in the latch (forming part of a lock) and the lock opens. The remaining switches are connected between reset pin 4 and ground. If any one of these switches is pressed, the IC is re-set and the output goes to its quiescent low state. Possibilities of pressing these reset switches are more when a code breaker tries to open the lock.
LED D5 indicates the presence of power supply while resistor R5 is a cur-rent limiting resistor.

Summary: Press switches SA SC in unison at first ,then press switches S1 S8 in unison just after releasing SA SC within 5 seconds,after releasing S1 S8 again press SA SC in unison within 5 seconds and just after it press S3 S4 in unison and your relay will be energised.

– You can enlose this circuit in a suitable enclosure and put digit numbers on all the buttons from 0-9. And remember the combination so only you can open the lock through the code. You may also add a green LED at the end just before the relay in series with a suitable value resistor so you can check the status of the relay if its on or off just as i have added in the breadboard circuit.