Hi, I'm trying to modify a wireless doorbell set so my father (he is deaf) will "see" when someone is at the door. I thought a wireless doorbell would be easy to modify and use it as a visual alert, besides being "portable" as he can take it with him (will be using a transformer as a power source, but still is portable). Not using batteries because I'm not confident he will notice if the batteries are with no energy left.
The wireless doorbell set has two units, the emitter of the radio signal and the receiver. The receiver has a small speaker and an LED that blinks twice when someone activates the emitter.
I am trying to replace the receiver's LED with an optocoupler and use it as a switch to start two timers, the first timer will be "on" for around 2 minutes, and the second timer will flash some bright LEDs during those 2 minutes. Power source is a 2A 5V DC out transformer. The bright LEDs use 450 mA at 5V, according to my old multimeter, so the transformer should be enough to handle that.
I built the circuit on a breadboard and it worked ok when using 2 or 3 normal LEDs, had flashing LEDs for a little more than 2 minutes. However when connecting bright LEDs they turn on only at the time I push the button, after that they turn off. I suspect this is because the sudden current demand of the bright LEDs are resetting or powering off the 555 ICs, but I have no tools to test that (only have an old multimeter).
Tried adding another 5V DC out transformer at the mosfet side, creating something like a low and high circuits (disconnected the bright LEDs from the positive side of the first transformer, connected the negative side of second to "ground" and the positive side to the bright LEDs). In this case it worked ok, the second transformer was powering the bright LEDs and the timers worked ok.
Below is the circuit I tried (got most of the parts from the internet and made a few changes). When the test work with the bright LEDs I will replace the push button and resistor at the optocoupler and connect it to the cables of the receiver's LED.
What could be the cause of this behaviour (brighter LEDs not flashing but normal LEDs do) and how can I correct it?
Thank you for your help and comments.
The wireless doorbell set has two units, the emitter of the radio signal and the receiver. The receiver has a small speaker and an LED that blinks twice when someone activates the emitter.
I am trying to replace the receiver's LED with an optocoupler and use it as a switch to start two timers, the first timer will be "on" for around 2 minutes, and the second timer will flash some bright LEDs during those 2 minutes. Power source is a 2A 5V DC out transformer. The bright LEDs use 450 mA at 5V, according to my old multimeter, so the transformer should be enough to handle that.
I built the circuit on a breadboard and it worked ok when using 2 or 3 normal LEDs, had flashing LEDs for a little more than 2 minutes. However when connecting bright LEDs they turn on only at the time I push the button, after that they turn off. I suspect this is because the sudden current demand of the bright LEDs are resetting or powering off the 555 ICs, but I have no tools to test that (only have an old multimeter).
Tried adding another 5V DC out transformer at the mosfet side, creating something like a low and high circuits (disconnected the bright LEDs from the positive side of the first transformer, connected the negative side of second to "ground" and the positive side to the bright LEDs). In this case it worked ok, the second transformer was powering the bright LEDs and the timers worked ok.
Below is the circuit I tried (got most of the parts from the internet and made a few changes). When the test work with the bright LEDs I will replace the push button and resistor at the optocoupler and connect it to the cables of the receiver's LED.
What could be the cause of this behaviour (brighter LEDs not flashing but normal LEDs do) and how can I correct it?
Thank you for your help and comments.