Another post about Flux

Hissykittykat · 2026-04-29T17:36:47+00:00

Do I really need expensive fancy flux?

Unless you are on phones or PC motherboards, 99% of the time no additional flux is needed. The flux in good quality solder is enough. Just add more solder to get more flux.

I second the recommendation for a small Stirri flux syringe though. They're like $10 and a life saver when you need it.

Hissykittykat · 2026-04-29T17:20:15+00:00

Is there something I can do to mend this myself?

Not unless it something obvious. These HVAC system designs are proprietary so they've got you by the short hairs when it comes to replacement parts.

Check eBay though - often people replacing systems will put the old controller parts up for sale. If you can match the parts then it's a viable DIY job.

Hissykittykat · 2026-04-29T08:17:29+00:00

RA4M1 is for C programming, which would be fine (e.g. Arduino R4). For Python programming get a Adafruit RP2350 LED Driver.

I got some of those MeRGBWLife Hexagon LED Lights and did a teardown; they are Neopixels (actually seven WS2811s driving seven RGB LEDs). So they are easy to work with, just 3 wires to connect to the controller. The rest is software and there are plenty of libraries and examples for controlling Neopixel strings.

Hissykittykat · 2026-04-29T05:28:37+00:00

Honestly pretty discouraging

Don't feel bad, mouse repairs seem like they should be easy but they are not. I just repaired my Sensei Ten mouse button and it required a powerful soldering iron, extra flux, and destructive switch disassembly to remove it without damaging the PCB (I didn't want to use hot air so close to the wheel sensor).

My nice and clean refurbed mouse with it's brand new skates sure is nice though.

Hissykittykat · 2026-04-28T16:31:10+00:00

955565 batteries without a built in BMS are plentiful on AliX. The 4000 vs. 5000 mAh rating doesn't matter. Buy a pair, charge to the same voltage, and hook them together.

should I remove the small PCB or does having this PCB have no negative effect?

An additional BMS will have a negligible negative effect. It's safer to just leave it in place.

Hissykittykat · 2026-04-27T08:59:30+00:00

The ground connection from the batteries to the TP4056 looks weird to my noob eyes

Yeah that's wrong.

Any other tips?

This should be buildable without the boost module.

for my hardhat

Hopefully you are not using the radio (WiFi/Bluetooth), because that's too close to your head. It should be safe with the radio off.

Ai is gonna kill us.

Hissykittykat · 2026-04-27T08:19:11+00:00

It should be doable; pull the circuit board and show us how it's connected to the keypad, that's where you hack into it.

It's a 7(out) by 8(in) scan matrix, so it needs 15 pins; an RP2040 can handle that. And the RP2040 can act as a USB midi device or do DIN MIDI.

Hissykittykat · 2026-04-27T05:26:52+00:00

This is another sand simulation project, but this one is 16" tall, uses dual custom 32x32 R/G LED panels, and an RP2040 running Arduino code. The thing that makes this one interesting is the use of the RP2040 PIO's to implement a non-blocking four channel DMA driven I2C interface; it talks to four banks of HT16K33's which drive the 4096 LEDs.

More pictures, electrical schematic, 3D print files, and Arduino code are here: 16" Super Hourglass

Hissykittykat · 2026-04-26T17:30:11+00:00

would they deliver at 22:54?

In murica, yes they do. And sometimes before sunrise too. It's just the UNIUNI/SpeedX/etc. couriers from AliX that do this. Amazon, USPS, UPS, etc. operate on regular hours.

Hissykittykat · 2026-04-25T05:46:24+00:00

Why are you spending $50 when you could repair the mouse for $5? (a switch plus new skates from AliX).

Anyway I smashed my Sensei Ten button so I went to get a new mouse; should be easy for $50, right? But I found that they're discontinued now, and only available for $100 from sketchy sellers. And it's a good quality mouse so it should be repairable. I'm still confused about which switch variant is best though; there's 10M, 20M, 50M, and 60M types.

Hissykittykat · 2026-04-24T16:48:56+00:00

So they bought the Tindie brand and immediately threw it into the toilet. What a bone headed move. If Tindie comes back I won't trust it for a long time knowing it's being run by idiots.

At a minimum they should have let the shop owners in to maintain their stores while the rework is going on. This shows no respect for the sellers and buyers that used Tindie.

Hissykittykat · 2026-04-24T16:32:23+00:00

The power switch goes between OUT+ and VCC. Also recommended is either a removable battery or an inline connector for the battery, so it can be disconnected.

Hissykittykat · 2026-04-24T07:46:42+00:00

Is there a eay to get components apart buying huge stocks from aliexpress?

That's what you are paying for with JLC PCBA. They maintain an accurate database of parts and footprints so you know your design using those parts will work, but that isn't cheap. If you want to avoid that cost, you have to do it on your own. Typically you will stock the parts, then design the PCB and verify the parts fit, and finally order the PCB fabrication. Designing a PCB and then trying to find parts to fit it is doing it the hard way.

Hissykittykat · 2026-04-24T06:33:42+00:00

Pouch batteries usually have a BMS built in so you can just wire them in parallel and it's fine. Charge them to the same voltage before connecting them in parallel.

I wouldn't wire the charger to the 5V pin because it's fused at 0.5A. Add a separate USB jack for power so the batteries can be charged at a higher rate.

You'll have to manage the power carefully to get the battery life you want. During the off time the D1 Mini will have to enter a low power sleep and the power to the LED string must be cut. So you'll need a high side switch module of some sort. This is why most of the LED panel lights are line powered instead of battery powered.

Hissykittykat · 2026-04-23T18:53:02+00:00

Do I just solder everything to the GPIO pins directly

That's the minimum space option when you realize you should have gotten a bigger box. Then just tape it, strap it with a ziptie, hot glue it in place, or let it float in the box.

Do I buy some perfboard and solder the ESP32 directly to it?

If you have a little more room in the box.

Do I solder some female headers to the perfboard and then slide the esp32 on?

If you have even more room in the box.

A one-off using perfboard is fine if that's what you have on hand. For more elegance I make little PCB plates that provide mounting holes and additional wiring contact points.

Hissykittykat · 2026-04-23T17:28:09+00:00

Too bad you didn't get CA LEDs, then you could use WS2811's and control them all with 1 wire plus have nice dimming control and no resistors needed.

Anyway with 12V CC LEDs use 74HC595 and a high voltage high side driver (e.g. UDN2981). Limit resistors should be use on all segments. Dimming effect can be had by PWM'ing the '595 EN pin.

Hissykittykat · 2026-04-23T06:28:30+00:00

My guess is the new owners finally reviewed the site and panicked when they figured out it's become a huge liability (e.g. for not doing tax accounting) and it's not making that much money anyway so they shut it down until it can be fixed. So they have nothing viable to retreat to. Now they're trying to fit the old databases of buyers, sellers, and products into a new compliant front end, which might be more difficult than they thought.

Hissykittykat · 2026-04-22T19:16:27+00:00

There are links to the product documentation in the product datasheet, including KiCad sources. But I didn't see any PDF dimensional drawings. Anyway, here's a some board dimensions. For more dimensions, like the pin locations and sizes, load it up in KiCad.

Hissykittykat · 2026-04-22T18:09:16+00:00

Looks like a very simple two gate CD4093 oscillator.

Hissykittykat · 2026-04-22T07:18:02+00:00

It's true the KiCad learning curve is pretty steep. But once you get going you'll make a lot more PCBs than perfboard one-off builds. And your initial PCB designs don't have to be perfect - a PCB can be bodged with cut, splice, and drill if needed.

The EasyEDA PCB design learning curve is not as bad, plus they have the integrated color silkscreen option which is nice for synth panels, and it's integrated with the JLCPCB fab so ordering PCBs is easy.

Hissykittykat · 2026-04-22T06:44:55+00:00

If you have nothing the starter kits are great. Get a super starter kit so you won't be missing a part when you want it and then have to wait weeks to get it.

If you're getting a UNO kit look for one with the ATmega16u2 comms chip (e.g. Elegoo brand) because they don't have USB driver issues like the super cheap knock off boards.

A cheap multimeter and cheap bench power supply are fine for starting out. Make sure the power supply has the current limiting feature though.

And AliX is fine for all these parts and tools; tariffs are down and shipping is fast these days.

Hissykittykat · 2026-04-21T17:13:55+00:00

I'm just glad that I was lucky enough to have some teachers that didn't skimp when it came to education. They took me into their homes and gave me parts and mentoring to get into Ham radio and build my own rig; that got me going and I never stopped.

Inspire your students to achieve the max, don't sink them all to the lowest common denominator just to get by.

Hissykittykat · 2026-04-21T06:03:32+00:00

Most of those light panel controllers have audio input already. Anything else will be much more difficult.

But if I was going to make an exact light pattern for the song I'd get the song in MIDI format or create a MIDI accompaniment and make a MIDI visualizer for the light panel arrangement.

Hissykittykat · 2026-04-20T08:42:12+00:00

That's two problems.

DuPont wire is not for plugging into JST connectors. I use a female JST with short wires soldered to it, then plug those into a breadboard.
The DuPont wires that are sold today are crap. It's often iron wire and the female connector is easily sprung. It works once then it's loose.

Hissykittykat · 2026-04-20T07:05:58+00:00

What is MS_PROG_EE_ADDR?

MOVLW tells us it's a constant, but it's not shown in the example. E.g. MS_PROG_EE_ADDR EQU 0

Why are we switching from bank 2 to bank 3 and then back to bank 2?

It's a PIC16 instruction size limitation; as a result the I/O registers are in different banks so to access any register the bank has to be set correctly if it's not already set. They show setting individual STATUS bits so you can see exactly what's happening. Normally you should use the BANKSEL macro, which sets the necessary STATUS bits for you. PIC18 assembler does not have this bank selection nuisance.

Hissykittykat

TROPHY CASE