Κυριακή, 1 Μαρτίου 2015

X125 oil change and oil filter cleaning

Not many people know this but the Honda XR125 does have an oil filter.It's not a regular type oil filter but it is a centrifugal one placed inside the right side engine case.Not easy to access.No wander why many people neglect it so often.They are not even aware of its existance!
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LM386 on steroids -buffed up amplifier!

This is the buffed up version of the LM386 amplifier circuit- the LM386 on steroids!

The R resistor sets the gain.It can be between 3,3R and 820R .But be careful. Too small a resistor can result in a lot of noise.I've used a 520 ohm resistor here.

Here is the schematic.Original schematic diagram was found here.

Here is the actual pcb.

Last but not least-the actual pcb layout.Print it as is.

.Pcb file for Pcbwizzard

If you don't know how to make the pcb  take a look at this.

read also
1/2 watt mini amplifier (LM386)
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Τρίτη, 24 Φεβρουαρίου 2015

Steering wheel replacement Honda XR 125

 Someone knocked over my motorcycle causing severe damage to the steering wheel.

 The steering wheel got all bent up on the right side.

So,I got a new one and replaced it.

Replacing the steering wheel  is not that hard.
You can see the whole procedure in the video below.
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Πέμπτη, 19 Φεβρουαρίου 2015

Αλλαγή σπασμένου τιμονιού στο Honda XR-125.(βίντεο)

Κάποιος οδηγάρας έκανε όπισθεν φαίνεται και μου 'ριξε το μηχανάκι .Το ξανασήκωσε,γιατί το βρήκα όρθιο, αλλά να σε τί κατάσταση ήταν το τιμόνι.Το στράβωσε εντελώς στη δεξιά πλευρά.

Ρώτησα για γνήσιο τιμόνι Honda ,45-50 ευρώ μου είπαν.Τελικά αποφάσισα να βάλω ένα άφτερ μάρκετ στα 25 ευρώ σε χρώμα κάρμπον με μπάρα στη μέση από νικέλιο.

Η διαδικασία αλλαγής του τιμονιού δεν είναι ιδιαίτερα δύσκολη.Δείτε την στο βίντεο που ακολουθεί.
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Τετάρτη, 4 Φεβρουαρίου 2015

Tin case pill box preamplifier! (40db)

This is schematic of the circuit based on this one .I've used a TL072 op amp instead.

Explanation of the circuit

The preamp has a gain of 100 (40db).Gain is set  by two resistors 100k/1k=100

voltage divider
This arrangement is for a single power supply.The two 47K  resistors and the .1uF capacitor is a voltage divider.

high-pass cut off
The 10uf and the 1k resistor at the input of the preamp (pin 2) set the high-pass cut-off frequency.In plain words -in this circuit-smaller capacitor less bass.Bigger capacitor more bass.

I've housed my preamp in this tin case box!This helps avoid  various noises.

I'm using 5volts to power the preamp here.More volts give out more power.

variable gain

You can use a variable resistor in place of R4 for variable gain.

This preamp is outputting to a TDA7360 amplifier bridge amplifier (22 watts)  an older project of mine.

Here is the preamp with switch,led light and knob added.
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Σάββατο, 31 Ιανουαρίου 2015

What frequencies can a human ear hear?

Human hearing range is from 20 Herz to 20 thousand Herz (20 kiloHerz).

There are a lot of variations between individuals.Hearing range declines with age.Children can hear higher frequencies.

For comparison, animals can hear higher or a lower frequencies than humans.

Elephants can hear lower frequencies from 17Herz-10kHz
Dogs can hear a lot higher than humans-up to 44kHz
Dolphins and bats are kings in the hearing range-they are able to catch frequencies as high as 100kHz!

Listen to video.What is your hearing range?
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Τρίτη, 27 Ιανουαρίου 2015

Motorcycle signal light flashing faster than normal.

This usually happens when a light bulb is out.

Look around your motorcycle for a blown bulb.
When a light bulb gets burned the total load is reduced and this causes some light to flash faster than normal.

The back right signal light bulb was blown in my case.I replaced it and everything went back to normal.

If all bulbs are ok then you probably is a grounding problem and you got a bad ground wire somewhere.

This fix can also be applied to cars.
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