Complete beginner seeking advice

[devlinse]

Hi everyone.

I'm after a few pointers to get me started and a recommendation for a book to start to fill in the many gaps in my understanding.

What I'd like to achieve is a bright light (LED / strobe) with a variable flash rate in the range 50-200pm. The flashing will be derived from real-time heartrate data and should vary without manual intervention. Eventually I'd be looking to accomodate upto three light sources to represent 3 different sets of heart rate data.

I'm assuming that one of the IO Warriors would get me started but a few pointers so that I can research the right area would be a real help. I suppose the two areas I'm most concerned about are power source (prefer standard batteries - what's required to 'join' it up to the controller? For 3 lights a PSU might be a better option) and timing control (I assume it's just a case of supplying/dropping current in time with my requirements) .

I checked out some bright LED's with 3.6v/700ma which sound like they'd do the job with an appropriate resistor.

Hopefully that's a clear description of what I'd like to achieve. I'm not after a full 'how-to' but some pointers for subjects to research so that I can figure it out - and ask more questions :-)

Cheers,

Simon

[Guido Körber]

Supplying high power LEDs via resistors is not a smart solution, you are wasting a lot of energy in the resistor and have to get rid of the resulting heat. In addition to cooling the LEDs this is no fun. You should consider to use the LED-Warrior01 to power your LEDs, in addition to being much more efficient it does also have a control input that can be used to switch the LED on and off via IO-Warrior.

We are currently preparing demos for the electronica show. One of the demos uses an IOW56 to drive a graphics LCD and the backlight of that LCD is driven by a LED-Warrior01-700, the IOW56 enables the backlight via the Mod input of the LED-Warrior. More info about the demos will be online as soon as we are done with the stuff.

I am not sure what you actually want to build though. The primary power source for the IO-Warrior is the computer it is connected to. The power for the LEDs would have to come from some power supply in addition to this.

[devlinse]

Thanks for the quick reply.

> Supplying high power LEDs via resistors is not a smart solution

Like I said, complete beginner :-) Do I understand correctly that the USB port would power the IOW56 and the LedWarrior-1 could be powered by a suitable DC input (battery?)

As for what I'm trying to built - people will wear the type of heart rate monitors used for exercise. These transmit wirelessly to a PC receiver which can read the Heart rate data. I wish to power a light in time with the heartrate - and eventually upto 3 (for different people). It's an arty thing. I've done the code to read the HR data I just don't know much about the electronics side.

I've ordered a couple of books to read up on the basics and will wait for your demo docs in the meantime. The LED-Warrior sounds perfect - I'm not trying to re-invent the wheel :-)

Thanks

[Guido Körber]

OK, in that case you should use a suitable wall plug power supply to get the power for the LEDs. USB supplies a maximum of 500mA at 5V for a device, that is not sufficient to power even a single 700mA LED. The LED-Warrior takes any DC input of 7V to 30V and converts it to properly power the connected LED. Keep in mind that the LEDs need cooling, usually a sufficiently large heat sink is enough to do this, better be on the safe side as LEDs start to age fast when getting too hot.

[devlinse]

Thank you. I'll do some reading and get myself some kit to get started on.

Cheers

[Guido Körber]

Application Note AN7 is now available for download, it shows how we use a LED-Warrior01-700 to power the backlight of a LCD module.