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Solid State Relay
Written by admin   
Tuesday, 08 February 2011 00:00

Authors: admin writes:

Solid State Relays are available almost everywhere these days, however they remain very expensive. Therefore, your efforts to build one yourself pays off. Especially since it only needs a handful components and the circuitry is simple and straightforward. A Solid State Relay is actually not a relay at all. There is no ‘relay’ present, just the electronics which does the switching. It works the same way as a relay; you can use a low voltage to switch a higher voltage or better.

Solid State Relay –[Link]

Last Updated on Monday, 07 February 2011 23:37
Simple GPS display using Attiny2313
Written by the machinegeek   
Thursday, 20 January 2011 00:00

Authors: the machinegeek

In his project, Binu from interfaces a ProGin SR-87 GPS module with an ATtiny2313 and 2×16 LCD to generate a running lat/long display. The device also will store one static location, and produce an audible alert each time that location is reached. (More locations could be provided for in code, but the project assumes the use of the demo version of BASCOM.)

This project also allows for the naming of the stored waypoint by entering up to 16 characters on a PC-AT Keyboard attached to the mini-din connector. (For those unfamiliar, the “10K SIP” in the schematic refers to a 10K bussed resistor.)

Source code in BASCOM along with a hex file is provided.

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Last Updated on Thursday, 20 January 2011 03:42
V-USB: virtual USB port for Avr microcontrollers
Written by the machinegeek   
Friday, 24 December 2010 00:00

Authors: the machinegeek

is a software-only implementation of a low-speed USB device for Atmel

Last Updated on Friday, 24 December 2010 01:08
Analog Level by BCD Thumbwheel Switch
Written by delabs   
Thursday, 09 December 2010 00:00

BCD Thumbwheel Switch is used to input-set data in digital form, this can be read by digital circuits, uC and uP systems and PLC-SCADA Interfaces.

In the early transition of analog to digital, before uP became acceptable, Digital systems without uP were made, it even had printers, RAM and displays. The uP systems were coming in, uC had not yet come and uP systems had to still win the confidence of the Prudent Industrial Design Engineer.

The drawbacks of uP based systems used in Computers, in those days were.

  • Power Consumption was very high, needed SMPS.
  • Many chips, a CPU had a Retinue of many chips.
  • Large Board, Double or Multi Sided due to Bus.
  • Fussy, Hangs on minor Power Glitches or Resets.
  • Needs Firmware Development and Tight Testing.
  • Investment in all these areas, Tools and Manpower.

These made Industrial Automation with uP a challenge. CMOS digital and mixed devices and custom application devices were more easy to implement and affordable.

The coming of Low power CMOS uC changed everything and embedded systems became smaller and robust. These were packable in DIN standard and DIN Rail Mounting enclosures.

Coming back to inputting digital data. CMOS uC and Ni-Cd Battery backed up RAM with keyboards made thumb-wheels and other methods less attractive for digital data inputs. Then the Li-Ion Battery, Flash Memory in Combination with Application Specific uC and SOC have made inputting, retaining digital data very easy and affordable.

Thumbwheels are mechanical memory like DIP switches, but have limited number of operations. Flash is Mechanical Noise immune, vibration will not shake the bits out of it. Thumbwheels are Electrical Noise Immune, data will not be corrupted due to Spikes, Glitches, EMI, RFI and Power Supply Failures. Yet thumbwheels cannot input or store an entire page of data.

Here is a Circuit that will help you understand or learn practically Digital to Analog Conversion. Practical Learning is very important for Technical Education. So you can easily wire this up and learn. This is an Inverting Op-Amp where Ri is varied using TWS. Vref can be from LM336 (-2.5V).

Analog Level by BCD Thumbwheel Switch

Ignore the DIP Switch part, When a 10 Turn Bourns Pot is used in place of Thumbwheel for Setting the Value, the DIP switch settings are changed.

(Information above is presented for edutainment purpose only, to create an appetite for learning - Cross Verify your learning acquired, from other Sources - delabs)

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Last Updated on Thursday, 09 December 2010 01:43
InfraRed LED Flasher for Optical Switch
Written by delabs   
Friday, 03 December 2010 00:00

This circuit is used to detect objects by reflected infrared light. It can be built into a cylindrical enclosure just like an inductive proximity switch.

This is also useful as a level detector for colored liquids like oil. This has some immunity to ambient sunlight as it detects ac pulses.

IC 555 is used as an astable oscillator and it flashes the Infra red LED D1 at a high speed, The object close to this LED reflects the light along with the ambient light which may also be sunlight.

Infra Red LED 555 Flasher

IR Led's and Diodes

The types available are various and polarity hard to detect even photo IR transistors can be used. The IR Led can be tested in diode mode of a DMM (battery should be in good condition) it should give around 1.1V drop in proper polarity. An IR detector diode or photo diode can be tested in the same way the drop will be 0.5V at 1 feet from a 60W lamp (no sunlight), closing the IR photo diode with your hand will be an over range on DMM this will happen on proper polarity. the photo diode shows around 10k ohm resistance in daylight and in Mega ohms when covered also the photo diode detects light on reverse bias and used like that.

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Last Updated on Friday, 03 December 2010 14:13
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