Reddit:Electronics

After a while i really wanted to make a pcb (or let a manufacturer produce it for me, like jlcpcb) and going from 1 idea to the next, i settled on making this somewhat universal usable pqfp-100 adapter board. The Z80 cpu was something i already had laying arround for a project, but dint want to spend too much design time if it where a dud.

Well, after designing the board, waiting a week or so. Soldering my first ever pqfp(or tqfp alike) it works ☺️ some wires to a generic z80 testboard and its walking the memory space for new instructions (all nop).

Now i need to programm a eeprom and get that pio and sio working. The pcb should also work for a RTL8019AS-LF network ic i got for a retro pc build.

Hello,

I decided to make my first remote controlled car design on KiCad, please do provide feedback. I'm using components such as an NRF24 modules, an L289N motor driver, and a stand alone AT328P.

The one thing that worries me greatly is I didn't add a connection to the reset pin on the AT328P, I left it floating, and upon further research, it is recommended to have a 10k resistor connected to 5V to the reset pin, otherwise it might reset randomly or not work. Is this true? I already ordered it so I'm afraid I can't do anything anymore if that's the case.

Thanks!

Here's a Microchip ATSAMD21G18A in a WeMos Arduino M0 clone, and here's the 48.007MHz clock brought out on a GPIO for inspection. That's the 32768Hz xtal oscillator multiplied by 1465 in the on-chip PLL.

I used a center tap transformer to step down the 110v to 9v AC, then I made a full bridge rectifier and smoothed it out with an electrolytic capacitor. Then, I used a Zener diode to regulate it to a smooth 5v. From my calculations, it has only a variation of .2%! Now I need a burner phone to test it on.

I finally decided to replace the tip of my Hakko FX-901 (the iron that runs on AA batteries). I’ve soldered all sorts of stuff with it over the years.

Created this pcb to learn how to drive SRM.

Firmware is open source though. A small (52x30) PCB to forward USB HID reports over BLE. Plus additional buttons and a rotary encoder.

Fully TTL driven Nixie clock I have been buildng recently. It have 6x IN-14 and 2x IN-19V Nixie tubes. Clock pulse is taken from mains frequency by optocoupler and devided by 7490 cunters. It can be set for 50Hz o 60Hz. There will be an option to choose beside Mains CLK, Crystal CLK and External CLK. There is also output to drive other clocks as "slave". Later on I will add "Day of the week" display.

Hey!

I repaired the LCD ribbon cable in a Nintendo DS Lite. I know it’s completely not worth it since a new screen is super cheap, but I wanted to practice soldering and test my skills. And it actually worked!

I intentionally placed a human hair on one of the pictures—for scale. I used an ultra-thin wire from a phone speaker coil to reconnect the traces. This was more of an experiment than a necessity, but the screen works like new, so mission accomplished.

The photos are a bit blurry since I took them with my phone through a microscope eyepiece—I don’t have a proper adapter.

All this effort for something that costs just a few bucks—but the satisfaction is priceless!

The first photo is a cross section from a 12pF 3kV capacitor along it's width. The second photo is that same capacitor along it's length.

The third photo is of a 47uF capacitor along it width, but with the layers in the wrong direction giving this damascus like texture. The fourth and fifth photo is this same capacitor along the width (the same orientation as the first photo). Unfortunately, not much can be seen here. I assume that the capacitor plates are too thin and densely packed for my microscope.

The sixt photo is of a (pretty bad) crimp terminal. It's just a random terminal I had laying around and I didn't know which cable size and crimping die I had to use for it.

The last photo is a cross section of a piece of solder wire, clearly showing its flux core within. I used it to hold the crimped terminal in place while the epoxy was hardening. That's why the crimp terminal can be seen behind it.

I still need to get vacuum pump to get rid of the air bubbles, and I also used very cheap epoxy so the clarity of it is not great. But for some first experiments, I think I can call it a success. Next up, I would like to capture some PCB details such as burried and capped via's.

I ran across this today for $5. I believe it is a PNP Germanium power transistor.

Along with mica insulators it has a note that looks original. It reads “2N278 transistors are not recommended for replacement in Delco built car radios.”

Max Voltage: 45VCEO, 50VCBO. Max Current: 15 Amp. Dissipation: 170 watt. Package: TO-36.

That is a lot higher dissipation spec than I expected.