Hi, I was wondering if someone can help me to adjust the circuit for my sons music/sound machine. There is a timer that limits it to 30min but I want it to play all night. I’d use the switch on and off button to turn it off. Thanks.

 

Better pictures of the other side of the PCB would be great, it's probably a small microcontroller that does the job..

 

Welcome to AAC.

Unfortunately, your sharp and well lit photos (thanks for that) only show the switch, which isn’t helpful in working out how this might be done. What we need is a view of the components on the circuit board.

That said, it is unlikely that any simple modification would work, but there is a chance that a simple circuit that restarts the timer when the sound stops could do the trick. We still need more information about what is on the PCB (Printed Circuit Board) to work out the details.

 

Better pictures of the other side of the PCB would be great, it's probably a small microcontroller that does the job..

Thanks for getting back to me. What is PCB?

 

Welcome to AAC.

Unfortunately, your sharp and well lit photos (thanks for that) only show the switch, which isn’t helpful in working out how this might be done. What we need is a view of the components on the circuit board.

That said, it is unlikely that any simple modification would work, but there is a chance that a simple circuit that restarts the timer when the sound stops could do the trick. We still need more information about what is on the PCB (Printed Circuit Board) to work out the details.

Thank you. I am not sure how to send more details on what is on the PCB unfortunately

 

Thanks for getting back to me. What is PCB?

Circuit board..

 

Thank you. I am not sure how to send more details on what is on the PCB unfortunately

In this marked up photo, it is the flat brown part in the red box (note that it is not all visible in your photo but is it one big piece). The yellow arrow is pointing at one of the screws holding it in. There are going to be more, probably four on the perimeter and probably one or two in the middle. This is just an educated guess, you will have to look for them.

Don’t remove any screws that might be there but don’t look like the indicated one, which is silver and very flat. There might be one or more that are holding something on to the other side of the PCB. Remove all the flat, silver ones and see if the board lifts out. Because there are buttons on the device that will have their switches on the unseen side of the PCB, make sure you have the face of the device down, preferably on a table, so the parts aren’t lost.

On the other side, along with the switches, there will be components that are variously flat black things and more round things that might be colorful. Everything on the board is of interest, but in particular and identifying marks (letters and numbers) on the flat black parts are important. If they don’t show up in the photo (they may be hard to see) please transcribe them so we have that information.

Again, be careful removing the ”board” (PCB), the switch parts might be finicky things but so long as you don’t force the board out you will be able to reassemble it. If you have trouble with disassembly, take photos of the board in place and tell us what you have removed to try to get it out so we can help.

The idea here is that we have to figure out how to “retrigger“ the timer. How do you do that manually? If the timer expires, do you press a button to restart it? Do you cycle the power? The likely solution is a circuit that “listens” to the sound and when it stops, does the electrical equivalent of whatever you have to do to get is started again.

It could be very simple, but you will have to venture into the would of components and soldering. That you‘ve dissembled it so far suggests to me none of it will be outside your ability even it it is daunting at first.

 

It will have a Blob chip underneath the pcb.

 

It will have a Blob chip underneath the pcb.

It may, or may not. The cost of cheap packaged MCUs has dropped so much that simplifying manufacturing by using a real package seems a lot more common. I am seeing much less of the potted dies on PCBs than in the past.

 

According to the manual https://www.manualslib.com/manual/1686971/Vtech-Baby-Lullaby-Sheep-Cot-Light.html?page=9#manual

7. Sound Sensor
Sound Sensor. Once the set time is up, the unit will automatically shut off. The sensor will reactivate the program when it detects baby's cry for approximately 2 seconds without interruption. The unit will reactivate and play lullabies or nature sounds depending on the selected mode.
8. Automatic Shut Off
To preserve battery life, the VTech will automatically shut off after the timer has expired. The unit can
be reactivated by pressing any button, sliding the mode switch or timer switch, or when baby cries.

Are you saying you want it to just keep playing regardless? Not sure how long it will last on 3 x AA batteries...

 

The unit can be reactivated by pressing any button, sliding the mode switch or timer switch, or when baby cries.

I wonder if it is actually detecting a baby cry or if it is any sound. Maybe it's looking for power in a certain passband rather than specifically a baby crying. Who knows, though, maybe they have real recognition.

Since any button press will work, that might be more fruitful. Or, maybe just toggle the mode with a relay every, say, 15 minutes between 20 and 30 minute selection and back.

 

Since any button press will work, that might be more fruitful. Or, maybe just toggle the mode with a relay every, say, 15 minutes between 20 and 30 minute selection and back.

Seems like a solution that will work.
One of the many relay timer modules available, such as from Amazon, could be used.

Might also want to consider powering the sound machine from the same supply as used for the timer (typically a 5V wallwort), since the batteries may have a short life under continuous operation, as J-H-T noted.
I would expect no problem running the machine on 5V, instead of the 4.5V battery supply, but you could put a diode (e.g. 1N400x) in series with the 5V to drop it to about 4.4V if concerned.

Edit: But considering the cost and complexity of this modification, a mains powered machine that will operate continuously, may be the best choice.

 

In this marked up photo, it is the flat brown part in the red box (note that it is not all visible in your photo but is it one big piece). The yellow arrow is pointing at one of the screws holding it in. There are going to be more, probably four on the perimeter and probably one or two in the middle. This is just an educated guess, you will have to look for them.

Don’t remove any screws that might be there but don’t look like the indicated one, which is silver and very flat. There might be one or more that are holding something on to the other side of the PCB. Remove all the flat, silver ones and see if the board lifts out. Because there are buttons on the device that will have their switches on the unseen side of the PCB, make sure you have the face of the device down, preferably on a table, so the parts aren’t lost.

On the other side, along with the switches, there will be components that are variously flat black things and more round things that might be colorful. Everything on the board is of interest, but in particular and identifying marks (letters and numbers) on the flat black parts are important. If they don’t show up in the photo (they may be hard to see) please transcribe them so we have that information.

Again, be careful removing the ”board” (PCB), the switch parts might be finicky things but so long as you don’t force the board out you will be able to reassemble it. If you have trouble with disassembly, take photos of the board in place and tell us what you have removed to try to get it out so we can help.

The idea here is that we have to figure out how to “retrigger“ the timer. How do you do that manually? If the timer expires, do you press a button to restart it? Do you cycle the power? The likely solution is a circuit that “listens” to the sound and when it stops, does the electrical equivalent of whatever you have to do to get is started again.

It could be very simple, but you will have to venture into the would of components and soldering. That you‘ve dissembled it so far suggests to me none of it will be outside your ability even it it is daunting at first.

thank you so much for your reply. It’s a bit too much for me to be able to follow. It would take me hours and I don’thave that time with a little baby.I thought it was going to be easier. Many thanks again for taking the time to reply.

 

According to the manual https://www.manualslib.com/manual/1686971/Vtech-Baby-Lullaby-Sheep-Cot-Light.html?page=9#manual

7. Sound Sensor
Sound Sensor. Once the set time is up, the unit will automatically shut off. The sensor will reactivate the program when it detects baby's cry for approximately 2 seconds without interruption. The unit will reactivate and play lullabies or nature sounds depending on the selected mode.
8. Automatic Shut Off
To preserve battery life, the VTech will automatically shut off after the timer has expired. The unit can
be reactivated by pressing any button, sliding the mode switch or timer switch, or when baby cries.

Are you saying you want it to just keep playing regardless? Not sure how long it will last on 3 x AA batteries...

yes, I want it to play regardless. I need to set an alarm on for every half an hour currently during the day to turn it back on so my son naps well. I thought it would be easier to do this but it’s too hard… thanks heaps for taking the time to get back to me.

 

Thanks all, I’ll just leave it. It’s too complex unfortunately

 

Thanks all, I’ll just leave it. It’s too complex unfortunately

Sorry it wasn't easier but if you have any other questions please don't hesitate to come back.

I just had a thought, depending on what can trigger it, I wonder if two of them started a few minutes apart would keep each other going...