mohan-bee - IMG20260730132508.jpg

https://tscircuit.com/mohan-bee/keychain

<@757706909351411845> <@&1420812538421051555>

Does it light up?

yeaa.. not that bright..

probably I need to change the battery

I wonder if there's any difference between shorting using finger or shorting using some jumper wire. So maybe it's not a battery, but the high resistance of your skin

Maybe some small touch sensitive switch components would be more reliable, though kind of reduces the coolness factor

TTP223 looks like a standard solution

yea i literally had this thought after placing order

okay then will soldering those copper pads .. work ??

The alternative is some mechanical jumper wire you put on the key chain. Makes you imagine being a car thief 🤭

lol

Soldering one end of the wire with some duct tape on the other pad maybe 🤔

Or some pretentioned spring

hmm... wil do

Just for fun, some calculations if you want to replace the battery

capacitive touch would be cool

Chip starts from $0.04 but requires aux components

MOSFET might be an even better solution. Short the gate pin with your skin, deliver full power to the led

yea that's cool

I assume the capacitive sensor is for use cases where the switch is hidden behind a plastic case. This is the opposite of that

like you said hand is the problem

check this now !!! did some alteration

i burned a led . By direct supply hehe

i am worst in soldering 😖

now added a 3v coin cell at the back

Now you need some OVP and properly calculate the value of those resistors 🙃 . Though 220k seems to be plenty

You used bench power supply instead of battery?

no i attached a coin cell at the back

i bought this module

Shouldn't have burnt out

no i just kept the 9v directly on the led terminla

so that burned only one led where i kept

Where 9v is coming from

no that is a seperate battery

and then i used this module at the back add a 3v coin cell

soldred

everything works

fine now

only without hand

Yeah, 9V is too much, red led requires around 2V.

yea

Lower resistance make them brighter. Though would make battery life shorter

yea that's ok for .. i do have a switch .. so i think managable ..

So BS_08_B2AA010_R is not used here: https://tscircuit.com/mohan-bee/keychain ?

no that was in the older version

haha that looks super bright

is there a resistor?

Yes