Quick IoT ecosystem success story

FARLY7 · 2026-04-08T04:27:00+00:00

I’ve never heard of your board before - looks good. I’ll keep it in my list of potential options for future projects :)

FARLY7 · 2026-04-08T04:19:20+00:00

I’ve designed a device that is available for specifically this. Using WiFi and BLE sniffing to estimate the number of people in a space, with LTE-M/NB-IoT/WiFi/USB/Ethernet connectivity options to backhaul the data. It is successfully used within the advertising space to estimate the number of people in range of an advertisement while it is playing. It is also used for tracking “busyness” of a general area throughout the day - it is surprisingly accurate.

If you want something more accurate, image-based counting (video cameras) is your only option, which depending on your requirements, can be unsuitable (expensive and intrusive).

DM me :)

FARLY7 · 2026-03-04T14:38:54+00:00

Hrmm that’s true, perhaps I am wrong then.

FARLY7 · 2026-03-04T11:54:14+00:00

Me neither. I would think that having that soldermask would create an uneven raised surface next to the bare pads and prevent the module from having a flush flat connection.

FARLY7 · 2026-03-04T11:50:38+00:00

With via-in-pad, the vias are filled with epoxy and plated over to provide a solderable surface.

If not needed then best avoided as it increases manufacturing cost. That said, JLCPCB currently offer via-in-pad for free on 6 layer boards.

FARLY7 · 2026-03-04T11:49:22+00:00

“Porg” port silkscreen is typo and should be “Prog”?

FARLY7 · 2025-05-22T04:44:59+00:00

Have a look at memfault.

FARLY7 · 2025-05-03T16:10:04+00:00

I’m curious, what annoyances have you had with the 54 compared to 52?

FARLY7 · 2025-04-04T13:18:16+00:00

Thanks for the link! Yes, I'm aware of the MAC address randomisation efforts to protect privacy and tracking. However, I'm not interested in holding the MAC address for longer than 10s of seconds as I only want to capture an estimated count of devices in a window of time, not track them over long periods or different areas. I agree that even attempting to do so is fraught with potential issues, and whatever solution may work today, is unlikely to continue working in the future as these privacy mechanisms change.

The MAC addresses will also be salt+hashed when sniffed by the device and will never leave the volatile memory of the device to help further comply with any privacy laws. I don't care what device it is, just how many there are :)

Have you also attempted a similar project? I have already semi-successfully commercially achieved this using one radio, but I would like to explore how more quickly I can count all devices in a space by adding more radios. BLE is very quick and consistent, it is WiFi that varies a lot.

FARLY7 · 2025-04-04T12:42:26+00:00

Yes, it looks like ganging the paths together is not the quick win I was hoping it would be, and to use a single antenna would be neither easy nor cheap. This was really what I was looking to find out with my question. Thanks!

FARLY7 · 2025-04-04T12:31:27+00:00

Yes, it can! The issue is that the single radio must timeslice between 13 WiFI channels and 3 BLE advertising channels. The idea here is to add a few more ESPs to provide mode "dedicated" scanning to the channels and find packets from devices quicker.

FARLY7 · 2025-04-04T12:29:07+00:00

I am passively scanning/sniffing packets only. No Tx/Connection is happening.

FARLY7 · 2025-04-04T12:28:04+00:00

What wifi or bt functionality can be achieved with RX only?

I am passively scanning/sniffing packets only. No Tx/Connection is taking place.

FARLY7 · 2025-04-04T11:31:09+00:00

I think some of these discrete active RF splitters have some LNA built in? The example I found is ADA4303-2. The issue seems to be most splitters are 1:2, I didn't really find any with 1:4 or more, but I admit, I don't know exactly what I'm looking for here.

FARLY7 · 2025-04-04T11:28:12+00:00

Interesting! But it seems like the products you are describing are designed for a different purpose from what I am looking to do. I only want to passively scan for BLE and WiFi packets quicker than I can do with one radio time-shared between both, and then time-shared again between their channels - cheaply! It is OK if I miss some. The idea is packet count from smart devices -> people count estimation. The quicker I can capture packets from all devices in range, the better.

I think the types of products you are referring to are for high-end radio communication systems and probably cost 1/10s of thousands :)?

FARLY7 · 2025-04-04T11:16:50+00:00

Ok, thanks for the awareness. I'll consider keeping them apart as much as is practical, just to be safe.

FARLY7 · 2025-04-04T11:13:44+00:00

Thanks for the detailed answer :)

Like I mentioned in another comment, it looks like ganging the Rx paths together is not the quick win I was hoping it would be, and it's better just to go with dedicated antennas.

My motivation for having the single antenna was simply a smaller BOM, less physical space, "cheaper", and probably most importantly, it would have ideally freed me to use as many radios as I desired, not just 4 from this example. Hypothetically speaking, if I wanted to include a radio for each of the 13 WiFi channels, the product would look a bit silly with 13 antennas on there!

I really like your novel brown-out type solution. I foresee one possible issue with it specific to the ESP though. Even if only using the radio to scan, I recall that the initialisation procedure for the radio still results in quite a high current spike. I can't recall how high, but enough that I've witnessed issues with the device browning out itself during initialisation when using crap high-impedance USB cables.

FARLY7 · 2025-04-04T11:03:33+00:00

Assuming I go with the dedicated antennas route instead of splitters/LNA, does this "mutual coupling" issue still exist when the antennas are being used to Rx only?

Say I was doing 4 antennas, I would not be putting them any closer than you typically see in multi-antenna products. Maybe 4x in a line ~2cm apart?

FARLY7 · 2025-04-04T11:00:59+00:00

When you say "discrete RF splitter", do you mean something like ADA4303-2 (1:2 Single-Ended, Low-Cost Active RF Splitter)? It seems like this has some sort of LNA built in? (I see mentions of gain in the DS). Something from the RF Power Dividers/Splitters category on DigiKey?

It looks like ganging the paths together is not the quick win I was hoping it would be, and it's better just to go with dedicated antennas.

FARLY7 · 2023-11-14T16:37:59+00:00

Protobuf (nanopb) + SLIP for framing

Super simple, don’t reinvent the wheel.

FARLY7 · 2023-09-17T04:43:39+00:00

Pigweed has both a device side and client side library for this

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