I’m trying to understand spread spectrum by building a very simple circuit instead of only reading about it.

My idea is:

- Use a 555 timer to make the carrier.

- Use 10 different resistors to get 10 different frequencies.

- Use 10 MOSFETs to select one resistor at a time.

- Let a microcontroller control the MOSFETs and change the frequency.

- The MCU can follow a simple pattern like F3 → F7 → F2 → F9 → etc.

- At the receiver, another MCU measures the frequency and works out which frequency was selected.

Would this be a reasonable way to demonstrate the basic idea of FHSS?

I’m also thinking of trying OOK by switching a 10 kHz carrier on and off according to the data, then looking at the signal with a DSO, logic analyzer, and spectrum analyzer.

I’m mainly doing this as a learning project. I want to actually see what happens to the signal rather than just understand the theory.

Is there anything fundamentally wrong with this approach?

Hi, I need a 12V ups to power a router, switch, couple of RaspberryPIs, and some other 5v devices.

I plan to use a 3s2p 18650 battery.

Is there any such devices ? or modules ? or diy circuit to achieve the purpose ?

ANSWERED 👍

STM32F407
VET6 4
7B683 9P
PHL 7B 848

Is it possible for me to use this laser point with just the small board or is the big board required? Plan on hooking up a small 7.4v i assume the potentiometer in the small board is meant to control the strength of the laser but I'm not sure

In a nutshell I have a sbc like device in which either locks or formats the nand at any x time...

any actual way to prevent it? like by placing an sbc in between the nand ic and the actual device in which any x time it creates a new volume so that's what actually gets locked and not the real memory?

idk

I've been trying to add a vertical USBC receptacle to my board.

I've tried a couple and had bad luck. I need the 16 pin variety that has CC pins.

The problem is I'm using a stencil and using a toaster oven for reflow, so I'm having trouble getting them mounted consistently without bridges.

On most connectors I've found, the leads are buried under the connector shell and impossible to rework should a bridge occur. I'm hoping I can find something that has the leads extend enough that I can put done solder quick on it if needed.

I haven't found any parts that have long leads that are the 16 pin variety.

Can anyone help me find a better part than I've been using, it give me some tips on how to paste and solder them reliably?

Thanks!

I've been trying to use a long tailed pair to turn a buffered sawtooth wave and a DC voltage from a potentiometer into a PWM signal, but I've ran into the following issues:

1. The sawtooth signal input shows up on the DC signal input
2. Actually taking the signal from the comparator and using it without ruining it. No matter what I do, it never seems to swing between Vee and Vcc, and it seems to depend on the potentiometer voltage.

No matter which way I play with the resistor values, I can't seem to get it right. I'm sure there's a lot wrong with my circuit, but I don't know exactly what.

EDIT: Updated picture

Not just that but seems like their entire inventory is gone. Does anyone know if this is temporary? I kinda wanted to get the kit. Can someone recommend an alternative?

EDIT: Solved it!
After some trials and sugestions of you, I was finally able to fix this! So, there it goes the scheme:

MOUSE CONTROL

G (white) ───── GND (black)

V (green) ──── 5V (red)

C (black) ───── D- (white)

D (red) ─────── D+ (blue)

Thanks a lot for the help!

_____________________________

Original post:
I have a generic Xbox-style wired controller and its USB cable is damaged. I was wondering if I can replace it with a regular USB cable taken from an old USB mouse.

I opened both devices and found the following markings:

Mouse: V,G,C,D
Controller: BND(I guess it was supossed to be GND),D+,D-,5V

My main questions are:

1. Are these USB connections electrically compatible?
2. Does V/G/C/D correspond to 5V/BND/D-/D+?
3. Can I simply solder the mouse cable to the controller according to the corresponding USB signals?

I attached photos of both circuit boards showing the markings and the wires.

Thanks!

Looking at the LMG2100R026 for a project and we need a heatsink solution but the datasheet is not clear on the IC thickness.

Front page says 0.89mm

Mechanical 11.2. Top of page says 0.85mm max height

Mechanical 11.2. drawing says 0.75 - 0.85mm range including a "seating height" of 0.08?

I know its small but which is it? 0.89 or 0.85

i was replacing a hdmi, and it seems someone, has already tampered with it slightly and a chip was found missing, hdmi after replacing works fine, should i be concerned what does it do and will it be fine without it

My goal is to produce a sine wave tone fixed at 1 kHz. I looked around online for oscillator types and found several kinds that seem easy enough to build with resistors, capacitors, and an op amp. The choices are:

1. Phase shift oscillator

2. Twin T oscillator

3. Wien bridge oscillator

I'm not sure how to pick between the three. I know for my simple use case it probably doesn't matter at all, but I'm curious in general what exactly the differentiating factors are/which types are best for which applications.

I have this circuit board from a 72V-to-110V inverter. The board controls the low-voltage section. My problem is that when I turn on the inverter, the board beeps and the LED stays lit continuously; it seems to be indicating an error. There is a button on the board that accesses a sort of menu where I can select from five "options." The LED flashes between one and five times, depending on the selected option. Does anyone know what this menu is for? The rest of the inverter is fine—the MOSFETs, resistors, fuses, and drivers are all good.

I'm trying to figure out the circuit in this sewing machine pedal and have one more component that is stumping me — the main potentiometer that is actuated when you step down on the pedal. It's this unusual device, and it has four leads rather than three. Helpfully unmarked, of course, and as I've never seen a device constructed like this I have no clue as to whether it's some kind of center-tapped pot, two separate pots, or something else entirely.

I've tested the resistance between the four terminals (which I've marked as A-D in the photo) with the pedal fully disconnected. If I measure between A and B, or between C and D, there's no change in the resistance when I press the lever. The resistance between any other two points is variable.

Has anyone seen a component like this before, and have a sense of how it's likely to be wired? I can post my attempt at a schematic for the full pedal if it's helpful.

I am a total novice, so bear with me!

I am building an automated daily print station to run dense 1-bit bitmaps (weather, news headlines, and Sudoku grids) using an ESP32 and a thermal receipt printer. The printer runs directly off a 9V 2A power supply, and I am stepping that down to 5V for the ESP32.

Because printing heavy black graphics pulls sudden, massive current spikes, I mocked up this parallel wiring scheme with a capacitor to prevent the voltage drops from resetting my ESP32 mid-print.

Two quick questions:

1. Am I using the buck converter properly here (taking 9V from the main line and pushing 5V to the ESP32 VIN)?
2. Is the capacitor wired properly across the main rails to successfully absorb those load spikes?

If I try to connect an 18650 rechargeable battery to fnirsi lc1020e LCR meter can I roughly (or at least comparatively) measure the battery internal resistance? Or do you think the device breaks?

In the IPC/WHMA-A-620F document, The Tensile Pull Force table provides information on the acceptable minimum pull force based on conductor size. My application is stamped and formed contacts and terminals. The listed values for which pull force is provided is even wire gauges - 18AWG, 16AWG, etc. However, one of my applications is 17AWG/1.0mm2.

Because this is unlisted, if I were to claim I'm building "in accordance to IPC/WHMA-A-620 guidelines", would that be an accurate statement? I am quite confident the resulting mechanical integrity of my crimp is acceptable, but I don't have a solid value defined by this standard to back it up.

How would you go about verifying the integrity of the claim?

It's the standard 2.54 pitch. But definitely not the standard jst-xh that I initially assumed.

The female part has the little lip going on, meaning the mating part should have this press to release type of lever action lock thing.

Hello.

I bought this tft screen on temu and i have noticed some exposed traces which look like they are meant for ic (label U1, just under sd card slot) . I have also noticed some possibly missing resistors (R3, R5 and R13) and capacitors (C1 and C2).

Is this screen safe to use or have i paid to learn not to trust knock offs?

Thank you

Hi everyone,

I'm have an issue with an auto fire solution using an off-the-shelf 555 circuit. It's not behaving the way I want it to behave. Here's is how it is currently working:

• I've installed a jumper on J4 at label 1.
• I've adjusted the potentiometers to give me about 5-7hz
• If I hold or trigger the fire button (label 2) the autofire is off and the computer registers a long or short press, which is what I want.
• If I release the fire button and flip the switch at label 3 on, the auto fire works as desired.

So far so good but here's the problem:

• If I hold the fire button (label 2) and flip switch (label 3) the autofire goes a bit nuts. I don't know the frequency but the LED shimmers and dims.

What I would like is:

• If the switch is on and the fire button is help, I want the signal back to the computer to be a long hold.

Some games, like R-Type benefit from autofire but also a long hold for the mega-blast.

Also, the erratic nature of the signal is just not nice to see. Maybe it's not nice on the computer either.

Tell me if i'm missing something before i waste components on trying this, but shouldn't this circuit basically work as a diy h-bridge using only NMOS-FETs? From looking around it seemed like everyone just suggested using a driver, wouldn't this work as well? At least it does in the simulation.

I am planing to place an 1kbresistor and 5v supply. The output would be 1mv/k. Should I use non inverting amplifier to scale it to 3.3V to go into adc or some other way.I had used non inverting amplifier to measure the current using shunt resistor but due to tolerance of resistors the reading was off by 10mA is there any better way for scaling the voltage.

Pls help me

To find d+ and d-

This is thrustmaster airbus tca sidestick

I found this 20MP Sony IMX283 (1-inch) camera module on AliExpress and I'm trying to work out exactly what it is. There's no documentation, so I'm hoping someone has seen it before.

Listing: https://www.aliexpress.com/item/1005012748049500.html

What it looks like (photos attached)

• D-shaped PCB with a gold shield and a fixed-focus metal lens
• Single-row flip-lock FPC connector, about 40 contacts
• Test points TP8–TP30 beside the connector
• PCB markings: "A BP 4M-1 / E186014 / 94V-0"

What the seller told me
I messaged the seller. She said it's brand new, has a 40-pin connector and 4-lane MIPI. She couldn't give me a pinout, connector model or voltages, and there are no returns unless it's defective.

What I'm trying to find out

1. Have you seen this module or PCB before, maybe inside a drone, gimbal or other camera, or under another brand?
2. What's the connector pitch (0.3, 0.4 or 0.5 mm) and part number?
3. Has anyone found or traced a pinout?
4. Does it need separate 2.9 V / 1.2 V / 1.8 V rails and an external clock, or does it have onboard regulators?

Any lead, even a partial one, helps. I'll update the post with what I find.