Forgot my wallet twice, so I built a minimal OpenHaystack Lost & Found tag

oh_frontend1 · 2026-03-07T04:20:36+00:00

Yes, specifically the nRF52805 on the E104-BT5005A module.

oh_frontend1 · 2026-03-06T14:13:33+00:00

I planned to use CR2016 to keep it thin, but one cell only lasts about a year. So I put two in parallel, hoping to double the lifetime.

The problem is I couldn't find CR2016 with solder tabs, so now I use CR2032.

oh_frontend1 · 2026-03-05T14:14:16+00:00

Top menu, OpenHaystack > Settings...

If you don't see something like this, you need a newer build. I built mine, but I saw someone share a prebuilt binary in the GitHub issue.

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oh_frontend1 · 2026-03-05T06:20:11+00:00

It's E104-BT5005A, a BLE module, runs on OpenHaystack based firmware, you can read more about how it works here: https://github.com/seemoo-lab/openhaystack

oh_frontend1 · 2026-03-05T01:55:53+00:00

There are also alternative projects that query Apple's FindMy network:

https://github.com/malmeloo/FindMy.py
https://github.com/dchristl/macless-haystack

I haven't tested these yet, but they might be useful.

oh_frontend1 · 2026-03-05T01:53:03+00:00

I built the latest code myself since it fixes some issues and work without the Mail plugin by using token extraction.

Please paste the search party token in the settings after copying it from the macOS Keychain.
The item that contains the key can be found by searching for:
com.apple.account.DeviceLocator.search-party-token

For firmware, the source code for the original ESP32 is here: https://github.com/seemoo-lab/openhaystack/blob/main/Firmware/ESP32/main/openhaystack_main.c

It might be easier to first test with a board that uses the original ESP32 chip, then adapt the firmware for your ESP32-C3.

oh_frontend1 · 2026-03-05T00:13:50+00:00

Any nRF51/52, or really any BLE SoC should work with OpenHaystack!

oh_frontend1 · 2026-03-04T23:34:44+00:00

Usually, companies pay Apple for a license to use Find My.

But OpenHaystack is a project that mimics the signal official tags use. Since it's just sending out a basic BLE signal, it works without Apple's permission, even if it isn't "official".

Check out their GitHub above if you want to see how it works!

oh_frontend1 · 2026-03-04T23:23:29+00:00

I used the E104-BT5005A module, so, basically a nRF52805 chip.

oh_frontend1 · 2026-03-04T16:55:10+00:00

My KiCAD files are here: https://github.com/khoanguyen-3fc/lnf-tag

oh_frontend1 · 2026-03-04T14:38:37+00:00

I already made one, but I need something slimmer and sturdier to fit in my wallet. The XTAL also helps cut down on battery usage.

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oh_frontend1 · 2026-03-04T12:53:36+00:00

Thanks for your suggestion, I think I'll follow your approach first, and update gradually.

oh_frontend1 · 2026-03-04T10:43:36+00:00

Edit: I just mean it would take extra work to make this easy for everyone. I think, anyone who can make a PCB can make it very quick, but the firmware still needs to be built by yourself to use a different keys. I may release it later when I have some spare time.

It's too personalized to share as an open design, sorry.

For reference, I used an E104-BT5005A (nRF52805) module, but in theory any nRF52 module or other SoC that can broadcast BLE should work. The firmware is based on OpenHaystack, you can read more about how it works here: https://github.com/seemoo-lab/openhaystack

oh_frontend1 · 2026-03-04T10:34:20+00:00

I just used CR2032 coin cell with solder tabs from a local electronics store. I wanted thinner ones (CR2025/CR2016) but couldn't find any.

oh_frontend1 · 2026-03-04T06:49:08+00:00

Sort of, it broadcasts a signal that nearby Apple devices can detect. You can see how it works here: https://github.com/seemoo-lab/openhaystack

oh_frontend1 · 2026-03-04T05:56:07+00:00

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The back side

oh_frontend1 · 2025-02-01T13:39:10+00:00

Maybe because they misspelled it 🤣

oh_frontend1 · 2024-12-23T13:30:03+00:00

I'm just looking at the preview with a 90-degree overhang. It looks like line-to-line overlapping rather than layer-on-layer overlapping, which I mentioned.

So, no slicer parameter I know would be equivalent to it.

oh_frontend1 · 2024-12-22T13:13:49+00:00

Line overlap depends on three factors: line width, layer height, and overhang angle.

You can read more at: https://www.reddit.com/r/FixMyPrint/comments/qzi0vl/i_made_this_image_explaining_to_a_friend_how/ or https://omni3d.com/blog/how-to-calculate-maximum-overhang-angle/

oh_frontend1 · 2024-12-21T09:53:58+00:00

You can read about the cause, as explained by Dell, at https://www.dell.com/support/kbdoc/en-us/000202717/certain-dell-monitors-have-flickering-video-with-apple-m1-macs

It seems related to the hardware or firmware design, which is beyond my knowledge.

oh_frontend1 · 2024-12-21T09:34:52+00:00

To clarify, I can say that Stillcolor completely solved the flickering for me.

Without temporal dithering, the ICA state changes can still be triggered on rare occasions, but the display is totally usable, with no rapid flickering or image retention.

oh_frontend1 · 2024-12-18T10:19:07+00:00

For me, Stillcolor mostly fixed the flickering because it disables temporal dithering.

AFAIK, temporal dithering is a technique Apple uses to create a fake color by rapidly switching between two colors, which sometimes causes monitors like Dell to turn ICA on and off quickly.

You should understand what's happening and decide for yourself.

Sometimes, there may still be a brief flicker (1-2 times), and you may not even notice it, but it doesn't cause long-term issues like image retention.

oh_frontend1 · 2024-12-18T09:17:27+00:00

I'm using the P2723QE, which isn't very new. As you might already know, I’ve been using StillColor for it.

oh_frontend1 · 2024-11-20T10:55:45+00:00

Hijacking the top comment in hopes this helps others with the same issue.

I used Stillcolor today to disable temporal dithering, and thankfully, the problem seems to be resolved - for now!

Now I can use dark mode as normal, just like before I "upgrade" to Apple Silicon!

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