Strat with Preamp Circuit?

[James Welsh]

For such guys I have a very simple solution - a microprocessor-based little PC board, like this:
[ATTACH=CONFIG]47380[/ATTACH]
The current consumption of the board is in a range of 20 uA. When the user plugs in the Jack, it measures the battery voltage. When it's greater than 7.5V it just switches of (and does nothing else). With the battery voltage between 7V and 7.5V it beeps ones (and again switches of). With the battery voltage between 6.5V and 7V it beeps twice, and so on. The sound is quiet but I'm sure the guitar player can hear it. There is no way to start with dead battery and the user is also notified what it the voltage of the battery. And the user is notified only when the battery voltage is below a certain threshold. The threshold may be changed in software.

You didn't ask about it, but here are my photos:

Eric Clapton Mid Booster - Eagle AudioEagle Audio

This is a neat idea but for me it's overkill for a battery in a guitar. I've never found it takes very long to do a quick check with a meter every now and then, or just replace it if you don't know. And I can't recall ever seeing a guitar completely shut down because of a battery so I wouldn't sweat it if I didn't check for a while.

Having said that I remember years ago a friend installing an LED in his guitar that would either come on when the power was on, or only when the battery was low, or something like that. Anyway, he thought it was the greatest thing ever so there are no doubt others out there that love these kinds of things.

[MarkusBass]

This is a neat idea but for me it's overkill for a battery in a guitar.

Thanks for the feedback. It seems to me that you think that I'm using something big like ATMega328 but it's not the case. The processor that I use is 2.5x1.5mm. You would have a problem trying to distinguish it from a transistor .
The main advantage of the circuit is that it has an extremely low power consumption and the user does not have to do anything to check the battery.

I've never found it takes very long to do a quick check with a meter every now and then, or just replace it if you don't know. And I can't recall ever seeing a guitar completely shut down because of a battery so I wouldn't sweat it if I didn't check for a while.

Do you say that guitar players in Canada and in the States usually have a meter and they check the battery voltage before a gig? In Poland maybe one of a hundred guitarist has a meter and they usually use it when something is not working (after the problem has occured, not before) .

Having said that I remember years ago a friend installing an LED in his guitar that would either come on when the power was on, or only when the battery was low, or something like that.

The circuits with LEDs have one drawback - you have to drill a hole in the guitar for the LED. And most guitarists don't want to do it.
My circuit does not require any changes in the guitar.

[nickb]

For such guys I have a very simple solution - a microprocessor-based little PC board, like this:
[ATTACH=CONFIG]47380[/ATTACH]
The current consumption of the board is in a range of 20 uA. When the user plugs in the Jack, it measures the battery voltage. When it's greater than 7.5V it just switches of (and does nothing else). With the battery voltage between 7V and 7.5V it beeps ones (and again switches of). With the battery voltage between 6.5V and 7V it beeps twice, and so on. The sound is quiet but I'm sure the guitar player can hear it. There is no way to start with dead battery and the user is also notified what it the voltage of the battery. And the user is notified only when the battery voltage is below a certain threshold. The threshold may be changed in software.

Quite brilliant, great idea

[J M Fahey]

For such guys I have a very simple solution - a microprocessor-based little PC board, like this:
[ATTACH=CONFIG]47380[/ATTACH]
The current consumption of the board is in a range of 20 uA. When the user plugs in the Jack, it measures the battery voltage. When it's greater than 7.5V it just switches of (and does nothing else). With the battery voltage between 7V and 7.5V it beeps ones (and again switches of). With the battery voltage between 6.5V and 7V it beeps twice, and so on. The sound is quiet but I'm sure the guitar player can hear it. There is no way to start with dead battery and the user is also notified what it the voltage of the battery. And the user is notified only when the battery voltage is below a certain threshold. The threshold may be changed in software.

Hey Markus, did I tell you before that you are very clever?

[James Welsh]

Thanks for the feedback. It seems to me that you think that I'm using something big like ATMega328 but it's not the case. The processor that I use is 2.5x1.5mm. You would have a problem trying to distinguish it from a transistor .
The main advantage of the circuit is that it has an extremely low power consumption and the user does not have to do anything to check the battery.
Do you say that guitar players in Canada and in the States usually have a meter and they check the battery voltage before a gig? In Poland maybe one of a hundred guitarist has a meter and they usually use it when something is not working (after the problem has occured, not before) .
The circuits with LEDs have one drawback - you have to drill a hole in the guitar for the LED. And most guitarists don't want to do it.
My circuit does not require any changes in the guitar.

I do see how small it is. In fact your picture has a Canadian coin for reference so I know exactly what the size is.
Don't get me wrong, I do think it's a clever circuit and something people would find useful if they worry about their battery life. That's just not me. I don't find it too difficult to keep a mental note of how much or little I've been playing lately, and check the battery during a string change. I always put a simple note on the cover to remind me when I installed the battery, like this:



And I can assure you that players here are just as unprepared as players in Poland When it comes to batteries the most common thing I see is people just assume because they changed it a month or a few months ago that it's probably time to put a new one in. So they just replace it, even though it might still have plenty of life left.

I agree 100% about the LED. I would never do it. But that guy was the type that loved to mod things, and loved to make sure it was obvious. We rarely agreed on what was good or cool hahahaha!

[MarkusBass]

Thanks guys. I'm not that smart. If I were smart, I'd be a top specialist in electronics in my country (as Juan is in Argentina). But it's not the case.

I So they just replace it, even though it might still have plenty of life left.

This is exactly the problem that my circuit solves. You don't need to remember when you changed the battery and you don't need to remember how long have you played using the battery. You are just notified exactly when it's needed. And musicians can focus on the music instead of old battery .
I think the circuit is helpful but there are other ways to stay on the safe side.