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Wednesday, 29 August 2012

Knight Rider Kitt / Cylon LED Sequencer Stripboard Veroboard Layout


This is a cool little project I've been meaning to do for a long time. One which was so simple I kept putting it off.
Essentially this is a 8Hz (ish) squarewave generator attached to a decade counter - it counts upwards displaying each count on the next LED however the outputs are wired in such a way that instead of just going upwards it goes back downwards. it should be obvious when you look at the schematic how the thing works.

Anyway as the name suggests the LEDS go back and forth like the eye things on Cylons from battlestar galactica or the front panel on the car from knightrider. my older brother drives a taxi so I plan on using this to drive relays to big lamps and attach it to his car when he's next away.

This circuit is very useful outside of replicating old TV show LED things, you can use it to sequence pretty much anything using relays or even digital circuits and you don't have to use the 555 to do it automatically, you can replace that with a push switch circuit to the CD4017 Clock pin (14) and control a pedalboard for example
or maybe even make your house seem haunted by using it to remotely control appliances. I will include a simple Relay Driver below.



To use the CD4017 to drive a relay


Saturday, 18 August 2012

Mosquito Repellent Stripboard Veroboard Layout


I'm pretty ill at the moment and I didn't want to really get up let alone make a circuit however the reason I am ill is because of bastard mosquitos - you see they bite you and your body reacts to the bites as it would a virus and with an illness the actual feeling of being ill is your body attacking the illness. in most people this reaction lasts a very short time and you don't notice it however with me any illness I get prolonged reactions, I always have which is why I feel really ill right now.
So in order to stop it happening again I thought I would make an electronic mosquito repellent

it mimics the sound the pregnant female mosquito makes which warns others to stay away.



Thursday, 16 August 2012

RIP Hans Camenzind


sadly, the inventor of the 555 timer IC passed today


Tuesday, 7 August 2012

Dual Tracking Power Supply Stripboard Veroboard Layout


another project born of necessity (ie I blew my other one up) This is a 1.5Amp dual polarity power supply (adjustable)

This may look like a waste of stripboard however once you see how big the 1000u caps are you will realize that you need the room.




Saturday, 4 August 2012

6 watt desktop amplifier stripboard veroboard layout


I wanted a nice powerful stereo amplifier for studio use, I'm pretty sure this will drive a few pairs of headphones/speakers though I've only tried it with one pair.
this would also be well suited for a nice set of powered monitors for a laptop or any other application.
anyway, I found the TPA1517 from Texas Instruments and it works great.

the powersupply needs to be very clean maybe even external to the unit itself. you'll notice there is a resistor across the terminals of the big capacitor (4700uf) this is a bleed resistor and its purpose is to discharge the capacitor once it is powered off, with the value stated it takes about 3- 4 minutes to discharge the 4700u 40v capacitor. it's not a necessity but it's advised to avoid electric shocks - even the 40 volt cap I used packs a nasty punch.

when you turn it on don't have your headphones over your ears - this is very very loud so the input signal needs to be raised very gradually