Hi! First post here so apologies if this is in the wrong place.
I’m building a LARP prop, a lantern with a resin-cast crystal inside with a green LED in it. The idea is that it represents a soul trapped inside the crystal, and every now and then (randomly between 15 and 80 minutes) it plays a whispering sound clip while the LED pulses. The rest of the time the LED just glows steadily.
I ordered the Tiny FX Starter Kit and want to power it with a 3.7V 1500mAh LiPo battery and a TP4056 module for charging via micro USB.
Here’s what I’ve planned so far:
For the LED I’m putting a 33 ohm resistor soldered inline on the positive wire with heat shrink over it, between CH1 and the LED.
For the speaker I’m using the one that comes with the starter kit, plugged into the SPK connector.
For the on/off switch I’m using a small SPDT slide switch. I want to be able to charge the battery without turning the whole thing on. My plan is to split the battery cable so one wire goes to the switch (and then to Tiny FX) and the other wire goes straight to the TP4056. But I’m honestly not 100% sure how to do this in practice and would love some input on whether this is the right approach or if there’s an easier way.
A couple of questions:
The TP4056 charges at 1A by default and my battery handles up to 1500mA, so I shouldn’t need to change anything on the module right?
I want the LED to pulse while the whisper plays and glow steadily the rest of the time. Is there an easy way to do this with the PicoFX library, or do I need to figure that out myself? I’m pretty new to MicroPython.
Has anyone done something similar or can point me to a project where Tiny FX is powered from a LiPo? Would love to see how someone else has wired it all up.
This depends on your LED, but I guess you have done the maths.
Yes, that is the rule of thumb. A 1500mA lipo can be charged with 1A.
I am not sure about this. The PicoFX library does not use asyncio, but at least for the LED-effects it is built for parallel effects. My guess it should be possible.
It would be much easier if you would use something like a Lipo Amigo Pro. The TP4056 is fine, I use it in various projects. One drawback is that it cannot safely charge a LiPo while providing power to a load¹. The good news is that you can cheat. The TinyFX is not a large load (at least in your setup), so I guess it would work anyhow. You will find tons of examples for the TP4056 that use it for charging and providing power to a load without split cables.
¹ The load will cause a voltage drop and this drop will fool the internal charging circuit of the TP4056, i.e. the charging circuit won’t shut down as needed.
You could provide a schematic/drawing of your wiring for further discussion if you like.
I have a TinyFX setup to light up a stained glass angle. I used the supplied LED’s and built in effects. No battery power with mine, it’s powered via the USB C jack and a plug in wall adapter. The angle is holding a candle that flickers with a yellow (led) flame, a red led simulates a blinking heart and her eyes and halo are lit up in soft white.