I just bought all the materials for my first diy lightsaber, which i am designing around a Proffieboard 3.9.
This build will be a gift for my girlfriend.
The idea here is to have a fully functional saber, with 2 neopixel strips as a blade, a speaker for the sound, a momentary button and a bluetooth module (fsc-bt909)… but i planned for it to be mounted on the wall for most of its life, as a (beautiful, i hope) lamp.
I bought a 18650 battery for the times it will be off the wall, but when used as a lamp i would like to power it using a 5V 10A Power supply.
I would also like to have it wired in a way that doesn’t charge the battery all the time, since i already have a 18650 charger and it would be really easy for me to remove the battery when needed.
Is it possible to do it?
Any advice on wiring it the correct way?
Every component in a proffie saber can handle 5 volts, except the battery. (accent leds may require slightly higher resistor values though.)
One way to make this work safely would be to print a battery replacement fob with a barrel jack in it. So you take the battery out, put the battery fob in, plug in the barrel jack in the battery and there you go… assuming you can find a space for the cable of course. Since the battery fob and the battery cannot be plugged in at the same time, it should always be safe.
There are other ways of course, but it gets a little trickier.
Thank you very much for your answer!
I just remembered that years ago i made several guitar pedals with both 9volt battery and wall power capability, i simply used those dc jacks with the switch mechanism. Could it be an idea also in this case? The wiring permitted the battery to power the circuit when no plug was inserted, and when an external power supply was connected the switch in the dc jack disconnected the battery.
Isn’t it possible to get something like that?
I’m thinking of that possibility because removing the battery will be easy, but not all that easy, and i don’t even have access to 3d printing, unfortunately…
Should be pretty straightforward I think, as long as you don’t need it to also charge your battery. It’s the same as a standard barrel jack charge port, but backwards, meaning that it disconnects the battery, rather than disconnects the board.
Oh nice! Then i think i will try to go in that direction… i only hope it is safe enough for the battery
Only one more thing: i suppose i should wire the external power supply to the +Battery in the board, is it correct?
Not sure I understand the question.
It will need to be connected to both + and -, or it won’t work.
The switch part of the barrel jack is always connected to the negative part of the barrel jack though, so the switch has to cut the negative path to the battery, not the positive, if that’s what you mean.
I’m sorry if i wasn’t clear enough… the question was about how to connect the external power supply, because i remembered i saw a 5V pin in the board and i forgot it is actually only an output.
Thank you and have a nice day