getting 5v for IC, best method

[gints]

Hey guys

im pretty n00b doing a team project at Uni, designing a circuit with some lights and buttons to make a Simon Says game (where you mimic the memory series of lights) and we are using at ATMEGA88.

For the MC and infra red, we need a nice 5 volts, using only alkaline batteries, and it has a long time.

I've read that in this type of application, 3v with a step up regulator lasts alot longer than a 9v batt with a step down, since the voltage drops too quick on 9v.

I just wondered what you guys think would be the best way to power this, and maybe some links to circuits that could show us how to generate this 5volts (obviously the rest of the circuit is done). Oh and we are on a budget, so piss cheap would be appreciated.

Cheers

 

[Tarsil]

Hey guys

im pretty n00b doing a team project at Uni, designing a circuit with some lights and buttons to make a Simon Says game (where you mimic the memory series of lights) and we are using at ATMEGA88.

For the MC and infra red, we need a nice 5 volts, using only alkaline batteries, and it has a long time.

I've read that in this type of application, 3v with a step up regulator lasts alot longer than a 9v batt with a step down, since the voltage drops too quick on 9v.

I just wondered what you guys think would be the best way to power this, and maybe some links to circuits that could show us how to generate this 5volts (obviously the rest of the circuit is done). Oh and we are on a budget, so piss cheap would be appreciated.

Cheers

See this http://www.techlib.com/electronics/regulators.html, is quite simple.
U can use the switching regulator above with 4-7 1.5V alkaline cells conected in series/9V batery.
SU and SD regulators have ~same efficiency.Te thing is that a 9V batery has a lower power/volume ratio.

 

[Nigel Goodwin]

Hey guys

im pretty n00b doing a team project at Uni, designing a circuit with some lights and buttons to make a Simon Says game (where you mimic the memory series of lights) and we are using at ATMEGA88.

For the MC and infra red, we need a nice 5 volts, using only alkaline batteries, and it has a long time.

I've read that in this type of application, 3v with a step up regulator lasts alot longer than a 9v batt with a step down, since the voltage drops too quick on 9v.

I just wondered what you guys think would be the best way to power this, and maybe some links to circuits that could show us how to generate this 5volts (obviously the rest of the circuit is done). Oh and we are on a budget, so piss cheap would be appreciated.

I can't comment on the AVR, so you will have to check the datasheets, but if you had used a PIC you could quite happily feed it directly from three alkaline batteries in series, or four NiCd/NiMh in series. Possibly an AVR might be useable in the same fashion?.

 

[Tarsil]

I can't comment on the AVR, so you will have to check the datasheets, but if you had used a PIC you could quite happily feed it directly from three alkaline batteries in series, or four NiCd/NiMh in series. Possibly an AVR might be useable in the same fashion?.

Yup is a good ideea.....The NiCd cels maintain a quite constant 1.25V/cell during most of their life. The 1.5V/cell for the allkaline is a bit less.

 

[zachtheterrible]

Yeah, a PIC16F628A for example has an operating voltage range of 2.0v to 5.5v