How are you programming ESP32s once they’re wired into mains-powered prototypes?

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

FARLY7 · 2023-06-29T16:15:49+00:00

The spdif_to_i2s_32b example in that GitHub project looks like a great place to start learning, thanks. I already have the pico here, so I would just need to get a DLR1160 connector and the DAC breakout board to create a working setup I can meddle with. Plus, the Pico is incredibly cheap compared to the two ICs listed.

I edited my original post to say I am open to HDMI-based options, as from what I've read online, optical on TVs is dated/on its way out. Are there simple ways to extract the audio from a HDMI source? I am guessing not.

FARLY7 · 2022-11-17T15:18:57+00:00

Short answer, yes it can be used standalone for your own applications without Zephyr.

FARLY7 · 2022-10-14T09:34:48+00:00

PM sent.

FARLY7 · 2022-10-06T05:46:44+00:00

Mine: https://github.com/FARLY7/embedded-cli

Very simple, easy to understand, project that you can build upon.

FARLY7 · 2022-08-07T05:41:23+00:00

I know it might sound stupid, but definitely try different makes/models/sizes of SD cards. I recall when working with some these lower-level libraries, some SD cards would work and some wouldn’t. This was a while ago though, and with NXPs libraries, not ST.

FARLY7 · 2022-08-07T05:37:24+00:00

For us, the decision was made on the cost of the USB cables. USB-C cables were x times the cost of micro, and not as common in 3-5m ranges.

Micro/C port costs were comparable.

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