Hack the Holidays Forum - Recent Threads

Bipolar White LEDs - It's a Christmas Miracle

scottiebabe — Fri, 30 Dec 2022 02:28:20 GMT

Soft 404

RE: Bipolar White LEDs - It's a Christmas Miracle

dougw — Sat, 31 Dec 2022 20:07:45 GMT

One advantage is that when driving from AC there is less flicker and better load distribution.

It also means you don't need to worry about reverse breakdown - only current limiting.

RE: Bipolar White LEDs - It's a Christmas Miracle

guillengap — Sat, 31 Dec 2022 17:54:41 GMT

What advantages does it have over Bi-color LED and RGB LED?

RE: Bipolar White LEDs - It's a Christmas Miracle

wolfgangfriedrich — Fri, 30 Dec 2022 02:40:20 GMT

That is really interesting. I knew of bipolar LEDs that were red and green, but those same colour one's seem to be made for string lights in particular.

Indecisiveness Before Christmas

DeltaPi — Thu, 22 Dec 2022 23:49:34 GMT

Have you ever had more than one project to work on and didn't know which one do to?

I do, as this happens to me a lot! This year I have three projects That I could try for the Hack-The-Holidays competition, but I don't know which one to go with, as I only have till January 11th. [emoticon:4b473fb4671244b2a5887318abe9e44a] So, I will leave it up to you guys. Please let me know which one you like the most and why, and any constructive criticism you have for me. Thanks, and merry Christmas!

Descriptions of the projects:

For Most Original I would make a "Naughty or Nice" sign that lights up one with LEDs depending on the emotion the Jetson Nano sees using AI.
For Most Festive I would make a Christmas light controller for Christmas lights you never have to take down, as they change color depending on the season.
For Most Artistic I would make a custom Christmas Countdown clock, that would get the date and time via Wi-Fi and display the day, also maybe telling a fun fact about the day.

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RE: Indecisiveness Before Christmas

DeltaPi — Fri, 23 Dec 2022 22:07:03 GMT

So everyone knows, the voting of the poll will end tonight at 10:00.

RE: Indecisiveness Before Christmas

DeltaPi — Fri, 23 Dec 2022 19:02:28 GMT

Hah! Sounds like an interesting idea. A nice way to burn off the holiday weight. 😁

RE: Indecisiveness Before Christmas

robogary — Fri, 23 Dec 2022 18:43:06 GMT

Naughty or nice could be really fun, gotta include corrective actions......:-) example: you've been nice, have a cookie, you've been naughty, do 10 pushups.

RE: Indecisiveness Before Christmas

DeltaPi — Fri, 23 Dec 2022 15:24:42 GMT

Good idea for the sign. I considered it having some sort of candy dispenser, so that might be able to be used on both occasions.

I really like the idea of modular lighting that can be set to patterns by the user. I have some extra small wifi modules that can directly connect to an esp8266, so with some relays it could easily control normal plugin things as well. The user interface reminds me of the lighting studio on some laptops for controlling rgb keyboards, so I might be able to get some inspiration there.

Sounds like a good way to make the clock useful throughout the year.

Thank you for the help!

RE: Indecisiveness Before Christmas

DeltaPi — Fri, 23 Dec 2022 15:01:49 GMT

Thank you.

RE: Indecisiveness Before Christmas

beacon_dave — Fri, 23 Dec 2022 12:36:51 GMT

The AI "Naughty or Nice" sign sounds like fun, and perhaps could be adapted into some sort of "Trick or Treat" for Halloween.

The Christmas Light controller could be expanded into a more generic room scenic lighting controller which allows you to add in the Xmas tree in December; Halloween pumpkins in October etc. into the overall lighting design and control then as part of one scene. Imagine a chase light effect that starts off running along the ceiling but then appears to drop down to the top of the Xmas tree where it then wraps around the tree in a spiral to the base before continuing along a floor level lighting strip. Remove the tree and the chase effect continues along the ceiling to the corner. A large portion of the design however will be the user interface in order to be able to easily program the scenes and effects if you move away from standard lighting protocols.

The Christmas Countdown clock could be expanded into a more generic countdown clock which counts down or notifies you of other calendar-based events (birthdays, holidays, etc.) as well as the fact of the day as suggested.

RE: Indecisiveness Before Christmas

dougw — Fri, 23 Dec 2022 07:08:25 GMT

All great ideas. I like the countdown clock idea - it is like the 12 days of Christmas....

RE: Have you ever made a 9V battery topper circuit?

ntewinkel — Thu, 08 Dec 2022 19:45:12 GMT

Very interesting!

I guess a dual led setup would be a cheap way to reduce flicker from 60hz to 120hz. The spikes make it seem like there’s no buffering.

I’m curious to see what you find out 😃

Also interesting for me to see how you used an oscilloscope in a direct useful application like this.

Have you ever made a 9V battery topper circuit?

scottiebabe — Wed, 07 Dec 2022 20:51:58 GMT

I never have!

I wanted to measure the optical flicker of some new decorative lights that are advertised as being "constant lit".

Naturally, I thought I would just use a reverse biased photodiode and current sense resistor on top of a 9V battery. Then combined with my handheld portable scopemeter I could measure the brightness of these LEDs versus time.

I sacrificed a new 9V battery snap for the endeavor. Perhaps one could salvage the snaps of an expired 9V battery.

So far things look okay. Time will tell if I end up breaking the 9V snaps off... lol

My First 9V Topper Circuit

If I make a second topper circuit I could make a much more luxurious version of this circuit which includes a dual op-amp in a DIP package.

Testing in the Garden

Finally I get to the point of why I built the circuit in the first place! I was curious to see if these product claims were even remotely true:

They claim to be shimmer-free:

At first glance there dosen't appear any addition circuitry in the string lights aside from the LEDs themselves. The plugs look ordinary

(This isn't a blog post or content for competition so excuse the blurry photos for now :) )

Are the LEDs constant-lit?

No, but interestingly they LEDs are active on both halves of a line cycle:

I am still think about this one, it isn't obvious there is a bridge rectifier nestled away in the strand or plug. Perhaps each "LED" has two LEDs in opposing polarities?

Old skool LED Christmas lights are only active one half of the 60 Hz line cycle

Interesting...

RE: Have you ever made a 9V battery topper circuit?

scottiebabe — Thu, 08 Dec 2022 18:48:22 GMT

Thanks, I'm still looking into how the full wave magic happens :)

This is wonderful! Its a fun low cost (I think I had 99 cents invested) and low time effort project theme. And its always fun to try new things 🙂.

That is one fancy topper!

I might try making a second topper which is a noise generator with an SMA output.

Not quite a topper but when I was a child I spent way too many hours using one of these:

For all I know my parents were damaging bulbs as a way to keep me occupied lol

RE: Have you ever made a 9V battery topper circuit?

dougw — Thu, 08 Dec 2022 18:32:52 GMT

That is a cute topper...👍🏽

RE: Have you ever made a 9V battery topper circuit?

ralphjy — Thu, 08 Dec 2022 17:24:18 GMT

Interesting discovery of "full wave" performance of the string lights..

I think you have inspired me to build some of my own 9V "toppers" using the Digikey contacts and 3D printed housings. Would be nice to have interchangeable modules for various functions.

I have a 6 LED 9V flashlight that I use for traveling (has a 2 LED and 6 LED mode). Getting a little dim, but I realized the expiration date was Mar 2016 😄.

RE: Have you ever made a 9V battery topper circuit?

wolfgangfriedrich — Thu, 08 Dec 2022 15:46:46 GMT

I use them for 5V circuits with rechargeables. But they also come as 6 AA holders.

PS: How do I insert a nice shopping link, like @dougw is able to do?

Maybe this?

6x AA

Looks different in the editor.

RE: Have you ever made a 9V battery topper circuit?

scottiebabe — Thu, 08 Dec 2022 14:55:57 GMT

LOL I have never seen these before! That's too bad they didn't use 6 AAs then it really would be a super 9V battery. I believe that's all that's inside a 9V battery 6 tiny (don't remember the size code) cells in series

RE: Have you ever made a 9V battery topper circuit?

wolfgangfriedrich — Thu, 08 Dec 2022 12:07:13 GMT

And then you can really confuse the circuit with battery holders like this:

Typical 9V terminals with only 4 AA cells giving ~6V. 😞

RE: Have you ever made a 9V battery topper circuit?

beacon_dave — Thu, 08 Dec 2022 09:55:58 GMT

"...Are you suggesting I use the bolts to make electrical contact as well? or only hold the battery..."

The bolts/rivets just passed through the holes in the centre of the battery snaps and through the PCB with a star washer onto the copper pad. I think some snaps have larger holes than others and some will take a countersink machine screw head without interfering with the battery terminal.

The battery then clipped on perpendicular to the PCB. Similar to Ralph's suggestion but with bolts/rivets instead of through-hole solder pins.

If I recall correctly, mechanical support to the battery was just provided by the enclosure. But I guess it could be easily provided by a 3D-printed plastic clip over the battery and into a couple of holes in the PCB.

RE: Have you ever made a 9V battery topper circuit?

scottiebabe — Thu, 08 Dec 2022 01:42:12 GMT

Those are neat too! And they have a version where the battery can sit on top of the pcb

I suppose if you snapped them to a battery before soldering it wouldn't be too difficult to get the alignment correct on a perfboard bare copper clad proto boards.

RE: Have you ever made a 9V battery topper circuit?

scottiebabe — Thu, 08 Dec 2022 01:36:33 GMT

Those look great! Thank-you 🙂 my previous experiences with 9V batteries were just like this:

The battery dangling/rattling around, sometimes I would drill a hole for strain relief. But then when the battery dies I never had fresh ones in stock.

Now that I have rechargeable that's not really an issue. They are handy when you want a low noise supply rail for a small circuit.

RE: Have you ever made a 9V battery topper circuit?

scottiebabe — Thu, 08 Dec 2022 01:31:06 GMT

O hello there little bond wire 🙂

I used a TEFD4300 photodiode because I had them.

If you were interested in measuring the flicker of a larger light source like an E26 lamp I think a small solar panel would be just fine too at 50/60 Hz.

RE: Have you ever made a 9V battery topper circuit?

dougw — Thu, 08 Dec 2022 01:02:16 GMT

Right angle PCB terminals....

Keystone 594 Keystone 593

These allow the PCB to support the battery.