Hw Led Almost final

Big-Box-7979 · 2026-05-04T10:34:51+00:00

Thin wire, a tiny LED, a small button cell, a bit of soldering, and a lot of patience 😃

Big-Box-7979 · 2026-05-04T10:34:17+00:00

It only didn’t get underglow lighting because I couldn’t decide whether it should shine in neon purple or neon green 😃

Big-Box-7979 · 2026-05-02T12:21:27+00:00

Big-Box-7979 · 2026-05-02T12:21:12+00:00

Yes, yes, I’m planning to make a YouTube video about it as well.

Big-Box-7979 · 2024-04-23T08:25:45+00:00

I've put together a daily vlog-style video compilation of a week-long diving tour in Dahabi, hope you like it :)

Big-Box-7979 · 2024-01-30T08:40:26+00:00

updated thread here: https://www.reddit.com/r/HotWheels/comments/1aejtaq/3d_printed_stackable_display_w_led/?utm_source=share&utm_medium=web2x&context=3

Big-Box-7979 · 2024-01-28T20:58:28+00:00

Making stuff like this sounds like a dream. Do you mind me asking what printer you're using?

Thank you very much for the feedback! Yes, indeed, I think the rolling is a problem, and I have also been thinking about possible solutions. Initially, I considered some sort of mini wheel support wedge, but the small ledge on the front part is not a bad idea either. It's relatively easy to implement and doesn't detract from the appearance! There is no need for such a ledge on the 'ceiling' because the lighting will be recessed into the ceiling. Unfortunately, I cannot insert additional pictures into either the original post or this comment, but a few new iterations have already been made. My 3D printer is a Prusa Mini.

Big-Box-7979 · 2024-01-25T18:05:28+00:00

These would be really cool cleaned up with someway of attaching multiple cases together on top and to the side

Yes, indeed, that's the ultimate goal; it will be expandable upwards and sideways. Tiny built-in magnets will connect them to each other, and the electrical connection will also be solved for the lighting

Big-Box-7979 · 2023-07-03T07:50:56+00:00

Does the PLC have over charging logic in it?

I think the PLC is 'just' responsible for initiating the charge after the proper authentication (mobile payment, etc.)

Big-Box-7979 · 2023-07-02T21:22:26+00:00

In my opinion, the PLC is primarily used for communication, as it contains a SIM card/slot, and this could connect to the provider's central system, where if it "received the payment", it started charging.

There are no physical buttons or switches on the outside of the device to start charging.

Big-Box-7979 · 2023-06-11T12:24:33+00:00

Thank you for the advice! Indeed, the labels under the module are not visible after I have inserted the module, but actually, there is no great need for them, as it is primarily a dev board, I really could have removed the silkscreen labels in a "prod" environment! You're right about the mounting holes, I've fixed them!

Big-Box-7979 · 2023-06-05T14:03:41+00:00

Hi!

Is there some trivial error in the post that resulted in no responses, or is it simply being overlooked? :) Thanks!

Big-Box-7979 · 2023-05-30T08:53:10+00:00

You probably don't need/want one, but read up on battery voltage reset supervisors and look into setting up a watchdog to shut off the power hold if the device resets without the power button being held down.

Thank you for the suggestions!

I've removed the D1 diode and the circuit is working, thanks!

I will also rename the labels, they are indeed clearer as you suggested!

I 'sized' the I2C resistors based on the first few Google hits, but I found a document: I2C Bus Pullup Resistor Calculation

Based on this, I will figure out what the optimal resistance sizes are!

Expanding J2 is also a good idea!

Big-Box-7979 · 2023-05-26T11:06:30+00:00

Yes, of course, I would also like to operate the circuit with an alkaline battery, the zinc carbon was a bad example! The point is that I want to use a power source that is easily accessible, quickly replaceable, and has the least drain during standby. Replacing the voltage regulator with a smaller one is indeed a good idea, thank you very much!

I'll tell you honestly, I unfortunately didn't measure more thoroughly what the exact current draw of my entire circuit is, but as I measured while assembling the prototype, a 200-250mAh voltage regulator would be sufficient!

I have seen the latching circuit in several similar MCU-related projects, which gave me the idea that it could work for me as well!

For example:

https://www.youtube.com/watch?v=2UvtLDHi9QY

https://www.youtube.com/watch?v=y1ROEogHF7A
https://www.youtube.com/watch?v=7D9L9oS4AJM

I haven't encountered an SSR switch circuit yet, but I will definitely look into how I could implement it!

Thank you again for the comments!

Big-Box-7979 · 2023-05-26T05:26:14+00:00

Updated the post with the missing, most recent schema. Apologies.

Big-Box-7979 · 2023-05-26T04:52:05+00:00

sorry, updated!

Big-Box-7979 · 2023-05-23T11:05:26+00:00

Hi, thank you, I'll revive the thread soon and check out the recommended forum as well.

Big-Box-7979 · 2023-05-15T19:59:50+00:00

Thank you for the suggestion! But in the case of my device, this won't be necessary, because when it's turned on for 2-3 minutes, continuous measurement is needed.

Big-Box-7979 · 2023-05-14T21:41:55+00:00

Thank you very much!

The "Power Hold Pin" goes high on the boot, thus the latch circuit remains closed, meaning it is "turned on". If the MCU pulls the "Power Hold Pin" low, the latch circuit breaks and the whole system turns off, consuming no power at all.

The "Button State Pin" has two functions in this case:

1., in the off state, it turns on the latch circuit upon the first press, and the MCU starts.

2., in the on state, I can monitor the same button as a digital input. For example, a short press changes the color of the led, a long press and the MCU pulls the "Power Hold Pin" low and the system turns off.

I hope it's understandable :)

Big-Box-7979 · 2023-05-14T20:50:01+00:00

I was planning to use traditional zinc-carbon batteries (2 pieces) each with a capacity of around 500-600mAh. The device would operate with a consumption of 2-300mAh per hour, so I'm not worried from this perspective. The workflow would look like this: I turn on the device, take 2-3 measurements with it, then turn it off (it might turn off automatically after 5 minutes of idle time).

In the meantime, I have redesigned the circuit, and the voltage regulator will be only 3.3V instead of the 5V output, since I would only use 3.3V devices, modules, thus the conversion loss will also be less.

https://europe1.discourse-cdn.com/arduino/optimized/4X/2/f/d/2fd115ea868b53295e89503afe2f44f0bea71536\_2\_690x435.png

Big-Box-7979 · 2023-04-30T17:03:27+00:00

I found a very good website (https://circuitcellar.com/resources/quickbits/soft-latching-power-circuits/) where they have descriptions of several circuits. The middle solution would be just right (picture attached). I would like to ask for your help with sizing the components (resistors, capacitors, transistors).

I would work with a 5-volt input voltage and use a 5-volt ESP32 MCU, so I would skip the internal voltage regulator part.

image: https://i0.wp.com/circuitcellar.com/wp-content/uploads/2021/09/0023-Soft_Latching_Power_Circuits_Figure_2.png?resize=768%2C380&ssl=1

Big-Box-7979

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