beep every 30s

[bob888]

Hi,

I'm working on a project where I have to take a picture every 30s with a canon 7d.
For that purpose, I need to have a small device that will generate a beep every 30s to warn the photographer.

This device will be attached to the camera using a tape. It must be of a small size[/B, as cheap as possible and generating a Beep as loud as possible.

Do you guys have any idea on how to do to that? I would like to buy the components online and build this device. I guess this will involve a piazzo and a microcontroler.

Thank you for your help!

 

[Pommie]

If you're able to program a micro controller then this is easy to do. What experience do you have with uCs and what language are you comfortable with?

Mike.

 

[DerStrom8]

If you're able to program a micro controller then this is easy to do. What experience do you have with uCs and what language are you comfortable with?

Mike.

I think it would be even easier to use a simple 555 timer circuit. No need to program a micro-controller.

 

[Pommie]

I nearly suggested a couple of 555s but as he mentioned uCs I thought he needed better accuracy.

Mike.

 

[DerStrom8]

I nearly suggested a couple of 555s but as he mentioned uCs I thought he needed better accuracy.

Mike.

I understand where you are coming from. However, I think that 555s can be quite accurate, as long as he knows the REAL values of his capacitors and resistors. He could also always have a potentiometer for fine-tuning to get the time period he requires.
Der Strom

 

[Nigel Goodwin]

I understand where you are coming from. However, I think that 555s can be quite accurate, as long as he knows the REAL values of his capacitors and resistors. He could also always have a potentiometer for fine-tuning to get the time period he requires.
Der Strom

Depends what you mean by 'quite', they are pretty inaccurate, and vary quite a lot due to temperature. A PIC, even running it's own internal RC oscillator tends to be more accurate and less affected by temperature - and of course if you use a crystal, you get crystal accuracy.

But the application doesn't sound very demanding, and a 555 solution may be all that's required.

 

[Reloadron]

beep every 30s
Hi,

I'm working on a project where I have to take a picture every 30s with a canon 7d.
For that purpose, I need to have a small device that will generate a beep every 30s to warn the photographer.

This device will be attached to the camera using a tape. It must be of a small size[/B, as cheap as possible and generating a Beep as loud as possible.

Do you guys have any idea on how to do to that? I would like to buy the components online and build this device. I guess this will involve a piazzo and a microcontroler.

Thank you for your help!

Interesting this is in homework help?

What you seem to be looking for is just something rhat will beep every 30 seconds correct? The camera type really has nothing to do with the 30 second timer. Therefore we can forget it as the timer beep will simply prompt an operator to do something.

Given the choices mentioned I would likely run with a micro controller based solution and I seldom suggest them. What you want to do is relatively simple using either a uC or discreet components. Using the uC you would get pretty reasonable accuracy and a very low parts count. The programming of the uC would be really simple (even I could do it and I am not a PIC type).

Everything could be easily fit into a tiny package including maybe a 4.7 volt or similar rechargable battery, similar to a cordless phone battery maybe. Easily hung on the camera strap. Beep of one second duration, count 29 more seconds and do it again.

Discreet components could also be used, just a matter of what you are comfortable with.

Just My Take
Ron

 

[colin55]

Do you want to use a piezo sounder or a piezo diaphragm.