turn on 4 LEDs one at a time in sequence at 0.1Hz and 100Hz. Choosing LEDs also

Hi, I want to turn on and off 4 different LED fixtures one at a time, one right after the other, turning each on an off 1,2,3,4,1,2,3,4... over and over until I turn it off. I am thinking to start at 0.1Hz so each light comes on for 2.5 sec then after I use the setup like that, start doing cycles at 100Hz, so each light comes on for 0.0025 sec. How would I program this project and manage it with a suitable power supply? I have not purchased an Arduino kit yet but will if I get a good feeling that using one is a suitable way to proceed.

I may need help picking lights as well. I need them pretty bright, I will be fine with white light for now. I will eventually move to IR lights, but for my early testing I need to see that the lights are on etc. I did go ahead and buy a ten-pack of super bright lights: Chanzon 10 pcs High Power Led Chip 5W White (6000K-6500K / 600mA-700mA / DC 6V-7V / 5 Watt) Super Bright Intensity SMD COB Light Emitter Components Diode. These were cheap and I can certainly buy lights that might be brighter or easier to integrate.

It sounds like an interesting project however you have a lot of homework ahead of you. When you read the wattage rating on a LED that is heat you have to get rid of so the led stays cool enough to keep from frying. The COB lights should be ok as they are already mounted. At this point do some research on LEDs, this will help you with the rest of the project. Next determine if you are going to use low or high side drivers. generally the Low side are the easiest. Next you need to determine a driver for them, consider a avalanche rated (it has a UIS rating) MOSFET. you will not need that for this project but maybe in others and not have to buy again. You can do this while your Arduino kit is on the way. Then break your project down to simple tasks such as timing, turning on and off outputs. Until you add the High Power LEDs you can run it off of your USB cable. Make a large sign that says Check The Grounds are They Connected and post it above your work area. Once you have the arduino and have it installed there are a lot of example programs included with the IDE, start with them and learn the process of programming and code writing. There is a tremendous amount of information available on the web. This response is to help you get started in solving your problem, not solve it for you. Good Luck & Have Fun! Gil

The demo Several Things at a Time uses millis() to manage the timing of blinking 3 LEDs and it could easily be extended to more. It may give you some ideas.

...R

jebb6: Hi, I want to turn on and off 4 different LED fixtures one at a time, one right after the other, turning each on an off 1,2,3,4,1,2,3,4... over and over until I turn it off. I am thinking to start at 0.1Hz so each light comes on for 2.5 sec then after I use the setup like that, start doing cycles at 100Hz, so each light comes on for 0.0025 sec. How would I program this project and manage it with a suitable power supply? I have not purchased an Arduino kit yet but will if I get a good feeling that using one is a suitable way to proceed.

After about 20Hz, will you be noticing the strobing? With one LED on at a time ,you have effectively a duty cycle of 25%. At the lower frequency you will see the LEDs strobe across, but as you go higher they will all appear as a single line of LEDs. Is this project for some particular application, or just an experiment? It is a good exercise to do, will be interesting how high in frequency you can go with noticeable responses.

Tom.... :)

I am evaluating a photodiode array sensor that was fabricated using the 0.18 micron CMOS process as a research project, so even though the LEDs will appear as "all on" at the higher frequencies, the sensor should be able to make serial measurements. The ultimate goal will be to cycle dozens of these or other IRED LEDs at 10kHz or higher. For now it will suffice to creep up on 100Hz, but by starting at 0.1 or 1Hz will allow my eyes to visually validate my first experiments. The faster the flash cycle, the faster I can move my sensor and still have valid correlation... Exciting!