Showing posts with label Home-Office-Automation. Show all posts
Showing posts with label Home-Office-Automation. Show all posts

Tuesday, August 09, 2016

Binary ASK modem - Power line Modem

Want hlp in dsigning of a binary ASK modem or Power Line Modem.

Mail from AM UK

Study these links ....
Amplitude-shift keying (ASK)

Amplitude-shift keying (ASK) is a form of amplitude modulation that represents digital data as variations in the amplitude of a carrier wave. In an ASK system, the binary symbol 1 is represented by transmitting a fixed-amplitude carrier wave and fixed frequency for a bit duration of T seconds. If the signal value is 1 then the carrier signal will be transmitted; otherwise, a signal value of 0 will be transmitted.

OFDM-Based Power Line Communication Modem

"The MAX2990 power line communication (PLC) baseband modem delivers a cost-effective, reliable, half-duplex asynchronous data communication over AC or DC power lines at speeds up to 100kbps. The MAX2990 is a highly integrated system-on-chip (SoC) that combines the physical (PHY) and media access control (MAC) layers using Maxim's 16-bit MAXQ microcontroller core. The MAX2990 utilizes OFDM modulation techniques to enable robust data communication using the same electrical network that supplies power to all other devices on the network."

LEDs Allow New Remote-Controlled Lighting Applications

LEDs Allow New Remote-Controlled Lighting Applications

PLC technology allows communication over a long range. New OFDM-based PLC technology, including emerging standards such as G3-PLC™, is simplifying integration of lighting control applications by providing noise immunity and interoperability.


Thursday, June 11, 2015

Lighting and Power control Automation

i am researching for a project for industrial automation . in this i am having one concept that is following below

if any one of person is in room the electrical power should be connected in this time one or more persons are entering in side that room at that time also that power should be ON .Now that persons who are all inside that room one by one is coming out that power should not be OFF but the last person who is coming out side off the room that power should be OFF

this is my concept of my project for this concept please design a circuit for me please send me replay for this concept

Mail from TM

You have to count people with optical switches or infrared detectors. Then using dsp or up processors and figure how best to establish number of people in room.

See below Motion Detectors - Professional and a DIY Version

Motion Detectors - Professional and a DIY Version

See a Related circuit here Optical Obstacle Switch.

A pair of optical switch-sets for every door that leads to room. Only if object cuts both beams then you count one. It is the idea you have to develop, Circuits are on the web.

See also - InfraRed Detector for Proximity Switch and InfraRed LED Flasher for Optical Switch

A pair of optical switch-sets for every door that leads to room. Only  if  object cuts  both  beams   then you  count  one. Even windows need sensors, if you expect some to use that for movement.  But some may slip in between beams, you might  have  see that happen.

Motion detector - Wiki

An electronic motion detector contains an optical, microwave, or acoustic sensor, and in many cases a transmitter for illumination. However, a passive sensor only senses a signal emitted by the moving object itself.

Other methods are RFID fixed on every person. Then it may be foolproof. Also as  most have cellphones, track the phones with GPS and count people in room.  A footrug with a weight measurement can also count people moving thru door. But a few may jump over them, so it has to be foolproof log footrug.

Updated - 10th Jun 2015

Tuesday, December 16, 2014

Sound activated RF remote relay

I am to build a circuit that operates off some kind of sound input into a sound activated circuit, preferably some kind of voice operated relay circuit. This relay is then to operate some kind of signal transmitter such as RF which activates a signal receiver and outputs onto a buzzer and an LED. It is to work something like a baby monitor, but in quite a simplified fashion, nothing too complex. I would be interested in circuit diagrams and related documents.

mail from CK

What is the max. distance between transmitter and receiver. Is it to monitor if the baby has woken up?

Voice Activated FM Transmitter - Alltronics

Voice Activated FM Transmitter - Alltronics

A sound activated switch and an FM transmitter joined together to make a voice activated FM transmitter. Set the level of sound that it will respond to. Two stage transmitter needs tuning to get best results. Tuning Kit and instructions enclosed. Transmits up to 1 km in the open depending on the aerial used. ZTX320 transistor specification.


The max distance between transmitter and receiver i would say would be no more than 20 meters or so. It should be designed to activate the transmitter when the vox detects noise up to 5m away, which would the trigger the remote alert device.

Look at a Solution here from TI (2014)

Baby Monitor TI App

Baby Monitor TI App

Baby Monitor is a capture and display system used to remotely watch infants. At the capture side, a microphone and a camera are placed near the child to transmit audio and video to the care giver. A parent talk-back audio system is also provided where baby can listen to the voice of caregiver.

A baby monitor is a video-based product used to see and hear an infant when the caregiver is physically not present near him/her.

I have already looked at a number of schematics and circuits i have found through my research on the internet and at my local library. I have already seen the circuit for the link that you provided, (Voice Activated FM Transmitter) and that would be ideal for the first part. I just need to know now what i would need for the receiver and remote alert unit: schematics, etc, and whether the receiver unit component values are dependant upon those of the transmitter. (All the receivers schematics I have found up to now are designed to receive speech and music like a radio.... I want to use the receiver to activate a buzzer and LED, as a remote alert device, I suppose this could also be used as a noise activated intruder alert system too!)

mail from CK

I am still trying to understand your requirement. 20 mts is quite small and is easy. What is the frequency range you need for min interference with your other gadgets. Also what are the parts your are looking at, do you need very low cost solution ? Is it just for your home use or is it for production ? will a toy circuit do ?

If you want a modern circuit, the best way is to use ready made modules. these may work at 30-200 Mhz range, some are AM some are FM.

The microphone goes to an amp which turns on one bit of the transmitter. The receiver decoded output can drive a buzzer, relay or LED as chosen.


20 meters is an adequate distance as generally the circuit is intended to be used around the house while the child is upstairs sleeping, so 20 meters should cover that quite well.

I have no other gadgets operating on radio frequencies within my home, so that should not really be a problem, i don't think.

I would prefer, if possible, an economic solution to this, a really simple circuit would do fine, however I don't want to purchase a 'hobby' kit to do this, I would prefer the circuit diagrams so I can see what parts for it i would need to get for myself...that is not a problem.

mail from CK

You must be able to study, build and test them and troubleshoot if required. i can just guide you to put things together, RF is delicate and difficult work. remember after all the efforts you put, it may not work, if you are not persistent.


Friday, October 24, 2014

Secure Entry Access Control - Smart Cards

I am working on an access system, multi-user code for entry to restricted areas. I designed one that uses purely hardware but its a bit complicated and bulky, though it works perfectly. Might you have any ideas on implementing microcontroller based systems. Any information would help me at this stage as i am still investigating my options.

Post by RT

These days smart card technologies are used for access system in most places. It uses a RF card the size of a Credit card with a microcontroller embedded in it. and you need a smart card reader that needs to be networked or interfaced with PC. philips, atmel, maxim, fujitsu and many more sources for kits, products and parts. many embedded 80C51 family type solutions were there when it all started.

Secure Entry Access Control - Smart Cards

Smart card, chip card, or integrated circuit card (ICC)

Contactless smart cards

A second card type is the contactless smart card, in which the card communicates with and is powered by the reader through RF induction technology (at data rates of 106–848 kbit/s). These cards require only proximity to an antenna to communicate. They are often used for quick or hands-free transactions such as paying for public transportation without removing the card from a wallet.

Like smart cards with contacts, contactless cards do not have an internal power source. Instead, they use an inductor to capture some of the incident radio-frequency interrogation signal, rectify it, and use it to power the card's electronics.

Study Resources Below

Smart Card Technology and Security 

A Smart Card and a Card Accepting Device (CAD) communicate via means of small data packets called APDUs (Application Protocol Data Units).

Useful Things for Smart Card Users 

Modules for Smart Card Microcontroller, Examples for application level Communication, Connection of a Smart Card to a Microcontroller, Instructions for Smart Card current measurement.
Other Notes

When this post was first made 8 links to sites with info was added by me. Today 2012 most of the links are broken. So new sites are listed.


Tuesday, March 11, 2008

Build RFID transmitter and receiver

Guide on how to build my own RFID transmitter and receiver?

Post by C1

You will find them here ...


This is an answer of mine to an old post - Tuesday 27 June 2006 22:34

Monday, February 12, 2007

Door access controller

I am trying to design a 4 door access controller. I have a complete working board of fingerprint scanner with DSP for fingerprint verification and authentication. I wish to design a microcontroller board which will communicate with this board to trigger the scanning process, store the data in PC and operate 4 relay circuits using the external wiegand relay output of the DSP. thanks in advance

Mail from RU

Have a look at these links

Look thru all the sites you may get ideas.