I have a bluetooth music receiver which has a battery and can output music though a 3.5mm jack and can be charged through a micro usb port. It has 3 buttons 1 for power and 2 for next/prev or vol up/down.
I want to modify the circuit, remove the battery and when I connect power to the charging port to automatically turn on without pressing the power button, i thought about shorting the power button but if you keep it pressed it turns on and after a few seconds it turns off. How can i change the circuit in order to give a short signal to turn on and then stay on while there is power connected. I attached the photos with the board and here is a link with the product from aliexpress.
I have a little Oontz my brother gave me years ago. To get around the On / Off button you need to know it's scheme in the circuit. Use a DMM and measure across the button under normal conditions (unit off). Do you measure a voltage open circuit? Most little devices like this have a normally open push button tactile switch. Normally that switch makes a connection to common (ground). ON my unit I need to hold the button in for a second for On and then a second for Off. If this works like I mentioned, using an internal pullup and the switch makes ground you may be able to place a transistor like a 2N3904 or 2N2222 across the switch. You need about a 1 second pulse which can come from a One Shot. The One Shot gets triggered when you Exrernally power the unit, it generates about a 1 second pulse which turns on the switching transistor for about 1 second simulating a 1 sec button press. This is all easier said than done making things fit. You could also use a micro to get the pulse but a simple 555 timer would work.
Ron_Blain:
I have a little Oontz my brother gave me years ago. To get around the On / Off button you need to know it's scheme in the circuit. Use a DMM and measure across the button under normal conditions (unit off). Do you measure a voltage open circuit? Most little devices like this have a normally open push button tactile switch. Normally that switch makes a connection to common (ground). ON my unit I need to hold the button in for a second for On and then a second for Off. If this works like I mentioned, using an internal pullup and the switch makes ground you may be able to place a transistor like a 2N3904 or 2N2222 across the switch. You need about a 1 second pulse which can come from a One Shot. The One Shot gets triggered when you Exrernally power the unit, it generates about a 1 second pulse which turns on the switching transistor for about 1 second simulating a 1 sec button press. This is all easier said than done making things fit. You could also use a micro to get the pulse but a simple 555 timer would work.
Ron
Can you please draw a lil schematic on how i should put the transistor? Yes it is like that, you need to press the button for around 1 second in order to turn it off. I looked at transistors but I didn't understand properly how to place it I'm not very experienced with electronics
I wouldn't assume this is possible without checking if the chip on the board can survive 5V. It may be
relying on the LiPo cell to provide a safe voltage. Try googling the part number on the chip plus the word "datasheet"
Regardless of how you get around the switch you still need to hold for at least one second, mine takes a little over a second. Be it a relay or transistor you still need some form of one shot which triggers when power is applied. Did you measure as I suggested and what did you get?
