LED Blinking current measure

[Jimmygoh78]

I have a project to measure current reading while LED blinking, what tools should I use because the current reading is 0.5A while on and 0A while off; 3 cycle of LED blinking. Thanks for help.

[GerdW]

Hi Jimmy,

apparently you need some DAQ devices. Which one do you use currently?

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@Jimmygoh78 wrote:

because the current reading is 0.5A while on and 0A while off; 3 cycle of LED blinking.

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You are reading 0.5A when the LED is on? Which kind of LED?

[Jimmygoh78]

I have DAQ device USB-6003.

This is LED lighting PCBA, 10LED in a board; so that current about 0.5A; but I need ensure the LED blink in 3 cycle. 

[GerdW]

Hi Jimmy,

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@Jimmygoh78 wrote:

I have DAQ device USB-6003.

This is LED lighting PCBA, 10LED in a board; so that current about 0.5A; but I need ensure the LED blink in 3 cycle. 

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How do you want to control that "LED lighting PCBA" (whatever that is)?

When you use a plain USB6003 you will need:

- add a relais to switch on/off that board

- use an external current sensor to measure the current, choose from a simple shunt (apply Ohm's law!) to some "real" current sensors (I prefer current transducers from LEM)…

I guess you know the basics of electrics/electronics/measurements?

[Jimmygoh78]

Can use software (programming) to measure blinking frequency instead of hardware measure?

[GerdW]

Hi Jimmy,

when the signal is outside of your computer then you need some hardware to bring that signal inside your computer. After this you can apply software analyzing the signal…

[Jimmygoh78]

I can measure fix current; for LED Blinking it may have 0A & 0.5A changing. I still thinking how to capture both current in a period (~15second).

[GerdW]

Hi Jimmy,

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@Jimmygoh78 wrote:

I can measure fix current; …

I still thinking how to capture both current in a period (~15second).

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What is a "fix current"?

To measure current over time you need to read more than one sample. Once you set a sample rate in your DAQmx task the job becomes easy as number of samples is the product of sample rate and time…

[daveTW]

For me the whole problem is not entirely clear.

In your first post you write, you have to measure a current.

In your second post you add, you have to control the number of blinking cycles.

Do you really want to measure the amount of current in your circuit or do you need it as an indicator for the "ON" and "OFF" state?

How do you want to control the cycle- count? What tolerance with your time measurement do you have to fulfill?

Please clarify these basic questions to give uas the chance to help you.

[Jimmygoh78]

Refer to below my reply.

1. Indicator for the "ON" and "OFF" state? Yes, need 

2. How do you want to control the cycle- count? Yes, 3 cycle

3. What tolerance with your time measurement do you have to fulfill? Yes, we have the tolerance for the time measurement.

I think above requirement can be measure by software programing? 

Thanks for your help.