fluorescent lamp damage alarm ?

[fireplus]

hi,

i need to design a circuit simply give alarm when fluorescent lamp stop working , can this done by current sensing or what ? :arrow: :? :?:
thanks for anybody wants to help

bye

Fire in the Wire :sm2:

 

[pisoiu]

Hi,
Try to make it by detecting if it emits light or not. You can use a photodiode, a phototransistor, photoresistor, depending on what you have. Current sensing methods may be more complicated than this one.

/pisoiu

 

[rauol]

8)

pisoiu
You can use a photodiode, a phototransistor, photoresistor, depending on what you have.

A good Idea but not commercially viable, Dust and moisture can have affect.


Bad lamp detection can be done in two ways 1: is to detect current and the other is to detect voltage acrose the LAMP.

 

[Ante]

I think current detection is more unpredictable than light sensing. The ballast and the ignitor and even the tube can still consume power when the light has gone out. The dust and moisture problems can be solved more easily.

Ante :roll:

 

[klug]

You can place a piece of wire along the tube. It will receive wide-band rf noise if tube is working. If lamp is broken it will not radiate steady rf noise.

Or even better - connect any contact of lamp to your rf sensor by little capacitor (3-5 pF will be enough). Capacitor will not pass 50/60 Hz AC, but will pass RF noise to your detector. Also it will not receive noise from air, as it has no big antenna and is isolated from power line by lamp filter.

Seems it will be very simple and passive - capacitor and two diodes detector with RC filter in output.

 

[fireplus]

thanks for your help,

but the idea of the ligth sensor is not practical beacause the fixture will have more than one lamp .

(The ballast and the ignitor and even the tube can still consume power when the light has gone out. The dust and moisture problems can be solved more easily.)

how can i solve the problem of the dust and moisture?

i think the idea of the rf is still have the same problem (that the fixture will have more than one lamp)

please if any body can give me more explain about his/her idea i will be thankful.

thanks for any body want's to help :wink:

Fire in the Wire :sm2:

 

[Ante]

What is supposed to receive the “alarm signal” from the detector? What kind of signal do you need, digital or analogue and at which level? What does your circuit look like so far, can you post it? I see no problem with sensing multiple tubes with optical sensors.

Ante :roll:

 

[fireplus]

hi,

i didn't design any circuit yet, i'm asking for help in how to start in this.

ante

you didn't answer my q about how we can solve The dust and moisture problems.

i will try to start by sensing the current and the voltage changes when a lamp stop working.

thanks for every body wants to help

bye


Fire in the Wire :sm2:

 

[pico]

I think you can sense the current for
1. no current means open circiut.
2. current change too often means the bulb or the start has problem.
3. current too much means ther is some leakage in the circuit.

 

[Ante]

Using components not sensitive to dust and place them on top of the tube trough the reflector can solve that problem. The moisture can’t be a big problem since the florescent lamp already works in the environment. If it is a wet environment the lamp is a sealed type and then there is no moist or dust issue here. And if you want to know if there is light or not then it’s light you should sense any other kind would be guessing I think.

Ante :roll:

 

[haymeron]

hi.

First of all, what is your ballast?
1. electronic.
2. magnetic.
3. both types.

The best way is to measure the current and voltage on each lamp.
The multiply VxI will give the lamp energy.
Or the logic [V and I] will give you the working lamp indication.

V lamp is: the voltage on the lamp at normal operation.