Thursday, November 17, 2016

Temperature control for CPU

My name is IS and I am looking for somebody to design and build a simple circuit that controls a small computer fan using either a 120V plugin or a battery using a temperature switch...

In other words I would give you the set point and at that temperature it would turn on the fan and when it drops below the set point it turns off the fan.. the temperature would have to be measured using a contact type measuring device like a thermocouple or thermistor.

Mail from IS Brazil

Go thru these links and visit all pages -
 Try this One Chip solution from Maxim Semiconductor

MAX6641 temperature sensor and fan controller

MAX6641 temperature sensor and fan controller

"Accurately measures the temperature of its own die and the temperature of a remote pn junction. The device reports temperature values in digital form using a 2-wire serial interface. The remote pn junction is typically the emitter-base junction of a common-collector pnp on a CPU, FPGA, or ASIC."

Some of my circuits are here Industrial Process Control Circuits
    delabs

    Wednesday, November 16, 2016

    Decade Digital Counter Module - LED and LCD

    I'm looking for a source of decade counters and wonder if you can help? I don't want to build the counter, I want to buy a functioning counter module.

    Do you have source suggestions?

    Mail from SF USA On 1/1/2011 1:34 AM

    Try These, some are kits, some ready modules.

    delabs has a resource on counters -   Digital Timers Counters and Clocks

    Easy way to build a counter since the 80s is using ICM7217.


    4-Digit, Presettable, LED Up/Down Counter

    4 Digit Counter Module - The counter module is supplied pre-assembled and tested and provides the building block for counter and timer circuits. 

    The counter module may also be used as an accurate digital timer with the addition of a suitable timebase and gating circuit.

    4017B Decade counter (5-stage Johnson counter) - Learn about the 4017 by building the DOCTRONICS Light Chaser Project:

    Multifunction Counter-Timer Electronic Kit K8035 - Counter-timer K8035 is a multifunction electronic kit that is handy for all sorts of counting and timing applications. Counts up or down from your own pre-defined starting point. Counter-timer can count each time you press the onboard push buttons, or count externally supplied voltage pulses.

    VM147 - Panel Counter MODULE - offers a very practical solution for counting parts, people, scorekeeping, etc.

    LCD counter module 7016 6-digit - Snap-fit module with 4-digit LCD and its own power supply (not included). This counter module is therefore suited to PCB-mounting (snap-in frame can be removed) as well as front-panel mounting

    Try Radio Shack ask for - LCD Counter Module - it may be expensive compared to above.
    delabs

    Tuesday, November 15, 2016

    Three Phase AC SSR for 1 HP Motor

    I need to build a three phase AC(in 120V)-AC(out 440V) solid state relay to turn on or off a small(1hp) three phase AC motor. Do you have any idea?

    Can I use three MOC3043 and three TIC236E triacs of course with all opto LEDs in series?

    Mail from FJP Brazil


    See my SSR Circuits , Solid State Relays or SSR Choose a DC Control and AC Load SSR, That is what you seem to indicate.

    1 hp = 745.699872 watts

    Let triac have 10 A and 600V AC ratings, BTA12600 But now BTA12600 is obsolete, adapt to what is available in your country.

    MOC3043 is fine, isolation must be good, take care. Use a Heatsink.
    ON-OFF Control inputs can be parallel not series.

    Here is a picture of a Solid State Contacter from Power IO

    Three Phase AC SSR for 1 HP Motor

    On this page you can see a 3 phase SSR i built. Three-Phase-SSR.

    delabs

    Tuesday, October 11, 2016

    Isolated RS-232 Serial Port Interface to SBC

    Subject: Help! - Date: Thursday, December 16, 2010, 4:40 PM
    Hello delabs
    I have question about one your project . The question is about the project RS232 with Opto-Isolation on schematics.dapj.com. I need this very much . Do i need to use max 232 or something else on uC side , or i connect directly on uc rxd/txd pins .I need this answer so much , im new in this . please help

    Best Regards
    Mail from SS (CC) - Russia

    This was done when MAX232 was not invented yet. This interfaces with PC well. If you want to make a PC based datalogger with 80C31, then this gives a safe PC to 80C51 SBC Serial Link.

    Suppose a Temperature sensor or a Heater Open up. If the High Voltage reaches the A/D and SBC. The PC will be next Victim.

    The Affordability and Product Safety Aspects, Including Fire Hazards; made me use this, as any other solution would make product expensive. An Opto-coupler and well designed PCB can give more than 2 KV isolation.

    The MAX232 does not have isolation, but look here Isolated RS-232 Transceivers. The MAX232 also generates a Higher Voltage level, like 10V for proper RS232.

     MAX3250

    The MAX3250 is a 3.0V to 5.5V powered, ±50V isolated EIA/TIA-232 and V.28/V.24 communications interface with high data-rate capabilities.

    The circuit i have made is very old and you can interface any serial uC with PC. No other chip is needed. It is cumbersome to build it and get it working for many. I suggest use one of these chips from Maxim unless you want to Adventure like me.

    delabs

    Thursday, October 06, 2016

    SCADA System - Project Idea

    I am a student of Electronics and Instrumentation Branch from BP. I am doing my training at ..... where i have been assigned a project to implement SCADA System using Microcontroller.

    Right now,i have a good knowledge of PSOC and AVR microcontrollers but since i am new to this technology,i am not getting how i should proceed for the project.i would be greatful to you if you can provide some information about the previous projects students have done in you organization regarding scada implementation.

    from MG

    A "SCADA System" may consist of a Human using a Computer with Special Software Overseeing a Process Control System made of many sensors, transmitters, autonomous controllers and actuators made of motor drives and heaters.

    SCADA System has a Computer, sometimes Network, HMI, PLC Control Panel, Secondary Slave Instruments. Autonomous Process Control in Remote areas and Protection and Fallback Units.

    SCADA System

    SCADA – Supervisory Control and Data Acquisition

    Some of these elements may send data to the computer which may Analyze and Indicate the condition of process or progress. The Human Operator can then fine tune the parameters of his system or study and record process cycles for quality and yield.

    You discuss this with your mentor and then build a part of it, or implement a part of it in an existing system. A whole SCADA system is too big a project, but a simulated or demo software interface project can be made.
    This will be posted comment on that post to continue. Any other doubt post as a comment, .

    delabs

    Monday, October 03, 2016

    Ultrasonic distance measurement

    The following was submitted on June 7th, 2007 at 01:47AM (PDT). message: sent me the ultrasonic distance meter circuit

    Mail from MS

    Design of an Ultrasonic Distance Meter

    There are several ways to measure distance without contact. One way is to use ultrasonic waves at 40 kHz for distance measurement. Ultrasonic transducers measure the amount of time taken for a pulse of sound to travel to a particular surface and return as the reflected echo.

    DIY Ultrasonic Rangefinder

    The ultrasonic transducers used in rangefinders like the Parallax Ping typically operate at about 40 kHz, but the surplus transducers I purchased have a lower resonant frequency of 24.50khz +/- 0.25khz.

    Ultrasonic Range & Imager.

    This is the electronic schematic of the homebuilt SONAR. Only one piezoelectric tranducer is used for both tramsmit & receive. This transducer is switched from TX to RX via the four 4016 switches. A high gain amplifier stage & rectifier translates the received echoes into voltage pulses.

    Ultrasonic Distance Measurement With the MSP430

    Ultrasonic Distance Measurement With the MSP430

    This application report describes a distance-measuring system based on ultrasonic sound utilizing the MSP430F413 ultralow-power microcontroller. The system transmits a burst of ultrasonic sound waves towards the subject and then receives the corresponding echo. The MSP430 integrated analog comparator Comparator_A is used to detect the arrival of the echo to the system.

    delabs



    Saturday, August 13, 2016

    CFL Lamps and Simple Inverter

    Kindly help me make one issue devoted to------ CFL Ballast Circuits----viz. circuits to drive a 5/7/9 / 11W....upto 18 watts CFL from a 6 volts / 12v DC battery, or Solar Panel,(or 220 volts AC Mains) Believe me, this is a crying need ,of the day, all over.

    The market is flooded with poor Lanterns, that work for 2 to 4 months then they can't be repaired even. Some makes are either high-cost/high Quality, or low cost - low quality. Custom Ballast ICs coming nowadays are no use, because they are obsolete in 4 to 6 to 12 months..

    Also, the circuit must have a (SMPS) power supply too, with overcharging * under voltage cutoff, as the CFL goes black, on being switched at low voltage.

    mail from SRM

    I can try to help you, Please Explain your need. Which way do you want me to help you.

    CFL Lamps and Simple Inverter

    A simple inverter for florescent lamps
    This inverter is very easy to construct, reliable, and even powerful enough to light up a 15W florescent tube (if you cool your transistor well). The only hard-to-find piece of this baby is the so-called yellow inverter transformer

    Oh no! Not Another CFL Inverter
    This one’s a beauty. It will drive multiple CFLs without the need for heatsinks on the MOSFETs. Fit heatsinks and you can run even more, up to a total of 100W.

    I can design with some SMPS type chips. Overcharging is only in Emergency Light Lamps. CFL's do not have this as they work on 230V. Make a more detailed specification. Then I can think more about it.

    delabs

    the problem is NOT that simple.............. problem is to RUN a CFL bulb, from a 6v/12v DC battery. Again, the problems are-----

    1)Efficiency, of energy utilization, in the battery
    2)Without using Custom LSIs(which go obsolete Unavailable in 6/12 months time and are replaced constantly ,by ever more sophisticated costlier models
    3)Blackening of the ends of CFL, near electrodes
    4)LIFE of CFL(supposedly--12000hours for European CFLs;8000hours for Advts;5000hours maybe ,reallife...
    5)Simple Circuit, which can be easily repaired in the field, by non-technical people in village/small towns.
    6)Low Cost--so, even the poorest person can buy use it
    7)Fast Charging , of the Battery(out of 24 hours--likely to be used for 4/6/or 8 hours .So, it has to be charged in the balance of 24 hours...
    8)Low Battery High Battery Cut-off; to prevent damage to battery CFL
    9)Compliance with the Basic Ignition Data, furnished by CFL manufacturers.These are like----filament voltage,Ignition Voltage, Current etc

    mail from SRM