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Archive for the ‘opamp’ Category

Gen
22

How to use infra-red (IR) sensor with Arduino

arduino, Comparator, IR, opamp Commenti disabilitati su How to use infra-red (IR) sensor with Arduino 

This article describes how to use infra-red (IR) sensor with Arduino or with a simple OPAMP comparator. Lee Zhi Xian writes:

What is infra-red (IR)? Infra-red is an electromagnetic wave who wavelength is between 0.75 microns to 1000 microns (1 micron = 1µm). Since infra-red is out of visible light range, we can’t really see IR with naked eye. However, there is a method to “see” IR which will be shown later on. Some of the infra-red applications includes night vision, hyperspectral imaging, and communications. We also use IR daily in our TV remote or any device remote.

IR transmitter and receiver can be obtained at low price. Their shape is looks exactly the same as LED. To distinguish between transmitter and receiver, the transmitter always come in clear LED while receiver is black in colour. Other than that, there is also receiver that is used to pick up specific frequency IR, 38kHz. For your information, 38kHz frequency IR is commonly used in remote control.

How to use infra-red (IR) sensor with Arduino - [Link]

Nov
07

Kit Review – Altronics Pocket Oscillator

altronics, K2544, kit, kit review, opamp, oscillator, pocket, review, TL064, tronixstuff Commenti disabilitati su Kit Review – Altronics Pocket Oscillator 

Introduction

In this review we examine the Pocket Oscillator Kit from Altronics, based on an design from (the now defunct) February and March 1989 editions of Electronics Australia magazine. The purpose of this oscillator is to give you a high quality, portable square or sine wave generator that can be used to test audio equipment, speaker response, fool about with oscilloscopes (!), and so on. The prototype basic specifications are as follows:

  • Frequency range: 41~1082 Hz and 735 Hz~18.1 kHz
  • Output: 1.27V RMS sine, 1.45V peak square
  • Load: 1.0V RMS sine into 330 Ω
  • Distortion: 0.16% THD at 1 kHz

Assembly

The kit is packaged in typical form, without any surprises:

Altronics K2544

In the usual Altronics fashion, the instructions are accompanied with a neat “electronics reference sheet” which covers many useful topics such as resistor colour codes, various formulae, PCB track widths, pinouts and more. The kit instructions are based on the original magazine article and include a small addendum which isn’t any problem.

Altronics_K2544_instructions

Unlike some kits, everything is included to create a finished product (except for the IC socket):

Altronics K2544 parts

… including a nice enclosure which has the control instructions screen-printed on the lid…

Altronics K2544 enclosure

However at this point I think the definition of a “pocket” is the same used by Sir Clive Sinclair when he had those pocket televisions. At this time I won’t use the enclosure as my drill press is in storage, however look forward to fitting the kit within at a later point. The PCB has a neat solder mask and silk screen:

Altronics K2544 PCB top

Altronics K2544 PCB bottom

Assembly was pretty straight forward, the original design has tried to minimise PCB real-estate, so all the resistors are mounted vertically. The signal diodes take this a step further – each pair needs to be soldered together:

Altronics K2544 diodes

… then the pair is also mounted vertically:

Altronics K2544 diodes mounted

However it all works in the end. The rest of the circuit went together well, and we used our own IC socket for the opamp:

Altronics K2544 assembled PCB

From this point you need to wire up the power, switches and potentiometers:

Altronics K2544 assembly

… and consider mounting the whole lot in the enclosure (or before assembly!):

Altronics K2544 lid

However as mentioned earlier, I just went for the open octopus method for time being:

Altronics K2544 finished

How it works

The oscillator is based around the Texas Instruments TL064 opamp, and due to copyright I can’t give you the schematic. For complete details on the oscillator, either purchase the kit or locate the February and March 1989 edition of Electronics Australia magazine. However the waveforms from the oscillator looked good (as far as they can on a DSO):

Altronics Pocket Audio Oscillator K2544 sine wave output

Altronics Pocket Audio Oscillator K2544 sine wave output

Altronics Pocket Audio Oscillator K2544 square wave output

Altronics Pocket Audio Oscillator K2544 square wave output

Conclusion

The oscillator works well, however the PCB layout could have been a little lot easier on the end-user. It’s time for a redesign, possibly put all the contacts for external switches around the perimeter – and allow space for the diodes to lay normally. Nevertheless – this is a neat kit, and still quite popular after all these years. For the price you get a few hours of kit fun and a useful piece of test equipment. So if you’re into audio or experimenting, check it out. Full-sized images are available on flickr.

And while you’re here – are you interested in Arduino? Check out my new book “Arduino Workshop” from No Starch Press – also shortly available from Altronics.

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

[Note - kit purchased without notifying the supplier]

The post Kit Review – Altronics Pocket Oscillator appeared first on tronixstuff.

Ott
17

Nebulophone microcontroller synthesizer project sounds great

arduino, arduino hacks, ATmega328, musical hacks, nebulophone, opamp, stylophone, synthesizer Commenti disabilitati su Nebulophone microcontroller synthesizer project sounds great 

Judging from the video (found after the break) the Nebulophone is one of the best sounding DIY synthesizers we’ve seen. Especially when you consider the simplicity of the hardware design. It uses an AVR chip and an OpAmp. The rest of the parts are just a few handfuls of inexpensive components.

The device was developed by Bleep Labs, and they sell the synthesizer kit seen on the left. But since it’s an open source project you can follow their design to fabricate your own, which is what [BlinkyBlinky] did with his offering seen to the right.

An ATmega328 drives the device, which is the chip often used in the Arduino Duemilanove. The keyboard is a set of traces hooked to the microcontroller. These are tinned pads on the kit PCB, but the DIY version simply uses some adhesive copper foil with a jumper wire soldered to it. The keys are played with a probe that makes the electrical connection, a common practice on these stylophone type designs. Chances are you have everything on hand to make this happen so keep it in mind for that next cold winter weekend that’s making everyone a bit stir crazy.

[Thanks Wybren]


Filed under: arduino hacks, musical hacks


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