The aim of this project is to remind people who forget to take their medicines on time. Elderly people because of their age usually forget to take their medicines. This project will help to remind the patient to take his/her medicine at prescribed time. The proposed system is best suited for elderly people and people who are very busy, as this device will not only remind them of their medicines with a buzzer sound but also displays the name of the medicine to be taken at.....
The aim of this project is synchronization of multiple motors using wireless technology. This project uses radio frequency to synchronize motor speeds. This is applicable to many industries like textile mills, steel plants, and paper plants wherein all the motors used on conveyor are desired to be synchronized. For example, in textile mills where multiple motors work simultaneously on a conveyor belt to draw clothes, it is essential that all the motors there should run.....
The project is designed to develop a pick n place robotic vehicle with a soft catching gripper. For example, it can safely handle a bomb very carefully to avoid explosion while catching. The robotic vehicle is RF controlled for remote operation. At the transmitting end using push buttons, commands are sent to the receiver to control the movement of the robot either to move forward, backward and left or right etc. At the receiving end four motors are interfaced to the.....
The main objective of this project is to intimate the concerned authorities about an unauthorized access of secured areas such as museums, residential houses, banks etc. As crime rate is on the rise and burglars are getting smarter, the security system for banks, shops and houses needs to be full proof. This proposed system ensures that at any moment if any unauthorized person tries to open the bank locker; a telephone number will be dialed through the telephone line.....
The circuit in Figure 1 is a keypad interface that solves this problem by using an ultralow-power microcontroller. The circuit typically consumes 100 nA while awaiting a key press and consumes a maximum of only 2 µA if all keys are stuck or held down. An added bonus of the circuit is that it requires no crystal...
his Electronic Lock circuit is not only simple but it is also very good. It can easily be configured to provide either momentary or continuous output. Key sequences of up to 9 digits are possible. You can pre-enter part of the combination and then have someone else enter the last few digits at a later time allowing for one-time access. This circuit has good debounce but there are some REALLY crappy switches out there so please look for types with spring or snap contacts......
This application note describes the implementation of an IBM MF2 compatible keyboard with National Semiconductor`s COP888CL or COP943C/COP880CL microcontrollers. Two different solutions have been developed. One solution, suitable for laptop/notebook keyboards is based on the COP888CL with special power saving techniques...
The circuit is easy to use. When you press "E" - current through D2 & R9 switches Q5 on - and the transistor energizes the relay. The 12-volt output moves from the "off" to the "set" terminal - and the green LED lights. At the same time - R10 takes over the job of supplying base current to Q5. This means that - when you release "E" - the relay will remain energized...
As shown in the circuit, Two common-anode 7-segment LEDs are connected to P1 with 180 Ohms current limiting resistor. Each segment of two LED are tied in parallel to P1...
The MM74C922N, a complete scanning keypad encoder, detects and encodes contact closures in a 16-key, X-Y switch matrix. A single capacitor or external oscillator sets the scan frequency. The encoder converts and transmits the closure as a corresponding 4-bit binary code. Integrating the decoder`s input voltage over an interval set by the key-bounce-mask (KBM) capacitor suppresses contact bounce...
The driver is a step-up converter using an inductor to boost the voltage, such as that from a lithium-ion battery, and bias multiple LEDs in series. The RS resistors in series with the LEDs balance out the current between the groups of LEDs. The LED forward voltage, typically around 3.5V, experiences some variation from one LED to the other for a given bias current, and the series resistors also compensate for that situation...
Moreover, the method does not entail programming and the concomitant, almost inevitable, debugging. A CD4016 CMOS analog switch, IC1, forms the heart of the system. Depressing the key labeled "1st" closes the topmost switch (between pins 1 and 2), which latches itself via the diode connected between pins 2 and 13. The same topology repeats three times, with the keys labeled "2nd," "3rd," and "4th."..
This circuit is very basic to build. To open a lock which is connected to the K1 Load, you must press each momentary switch in the correct sequence. The sequence used in this circuit is S1, S2, S3 and finally S4. If any of the other switches are pressed the circuit will be reset and you will need to start over. ..
You can divide a large keypad or keyboard into sections of 12 keys each (Figure 1). Each section connects to a separate comparator circuit, which detects a keystroke and generates a trigger pulse using the monostable circuit of IC4, and you can add more sections in the same manner. Diodes D1, D2, and D3 couple and isolate the comparators` outputs to Pin 2 of IC4. Each keypad section connects the same selection of timing-resistor values to the monostable. Therefore, each.....
When any particular key is pressed, its value will appear in BCD form at the outputs (A, B, C & D). It will remain there until another key is pressed. The 12 keys produce outputs up to "1011". Extended to 16 keys, the circuit will give the full HEX to BCD conversion...
If you have no parallel ports available for this purpose, you could use a standard RS-232C port. With the method shown here, you need only some wire and a few passive components to connect a keypad with as many as 15 keys to the RS-232C port, at distances to 50 ft...
This simple circuit is the electronic version of the combination lock. Using the special purpose LS7220 digital lock IC, the circuit allows a 4 digit combination of your choice to activate a relay for a set period of time. This relay can then be used to trigger a lock solenoid, enable a starter button, open a motorized door, or many other tasks that require a momentary signal...
First, consider some ways to effect key reading. Table 1 presents a comparison of four methods with references to circuit configurations (Figure 1, Figure 2, Figure 3 and Figure 4). As you can see, the best choice for reading many keys is to use the A/D converter that is inherent in many microcontrollers...
The system is simple to operate. After you install it between the keyboard and the PC, the keyboard functions normally until you close the toggle switch, which puts the circuit into "acquire" mode. The system then bypasses the keyboard and "types" data into an Excel spreadsheet column at the rate of 1 point/sec. When you switch off the system, the circuit finishes sending the current data before returning control to the keyboard. The slow sampling rate gives Excel time to.....
First, using interrupts frees the microcontroller to perform other tasks or to switch into an idling or power-down mode while awaiting the next key closure. Second, using interrupts helps reduce electromagnetic interference produced by continuously scanning the keypad`s lines. Figure 1 shows an interrupt-driven keypad implementation that`s based on Atmel`s AT89C52 version of the popular MCS-51 family of microcontrollers...
Operational Amplifiers
Computer Systems
Oscilloscopes
Transmitters & Receivers
Sensors & Detectors
ANSI Standards
Low Frequency Amplifiers
Power Amplifiers
Number Systems
Regulated Power Supplies
Analogue Filters
Digital Gates
