Page 2 – Hermetry

Posted April 28, 2026 at 7:41 pm · in 300 substation monitors: do I really need a separate MQTT topic per device? #6

ah ok, so custom topics are the legacy-firmware escape hatch. I’d mixed those up, thanks.

Measure twice, poll once.

Posted April 22, 2026 at 4:11 pm · in 300 substation monitors: do I really need a separate MQTT topic per device? #2

I think you set custom topics in the device profile for that? I saw a “Custom topics” option somewhere when I was setting up mine.

Measure twice, poll once.

Posted March 29, 2026 at 4:55 am · in My own ESP32 board needs the BOOT button for every upload – how do dev boards use DTR/RTS? #2

Maybe try a lower upload speed in the IDE? That fixed some upload errors for me.

Measure twice, poll once.

Posted March 25, 2026 at 12:39 am · in Wiring a MAX31855 to a Pi 3: the guide says MOSI, my board has no MOSI pin #4

Wired as you wrote, reads 21.75 C at room temp and 287 C with the oven on. Megan’s guess was my first guess too, nothing came back except zeros, so that would have been a long evening.

Measure twice, poll once.

Posted March 20, 2026 at 6:10 pm · in First project: Zigbee or Wi-Fi for eight office sensors? #6

Did the Wi-Fi temperature ones this week, all 4 on the board. Zigbee sticks and contacts arriving Monday. The “battery end devices don’t route” bit saved me from buying 4 more contacts to “build the mesh”, which was my actual plan.

Measure twice, poll once.

Posted March 20, 2026 at 12:18 am · in First project: Zigbee or Wi-Fi for eight office sensors? #4

The temperature ones can be on USB power, there are sockets nearby. The door contacts have to be battery, nobody will run cables to fire exits.

Measure twice, poll once.

Posted March 5, 2026 at 1:22 pm · in Pi gateway that moves between home WiFi and a phone hotspot at the allotment #2

Bookworm uses NetworkManager now, so wpa_supplicant.conf isn’t read anymore. nmcli is the way.

Measure twice, poll once.

Posted February 25, 2026 at 2:22 pm · in Putting my ESP32 sensors on their own network: what do they need to reach? #4

I think you’ll need to forward 8883 on the router to the ESPs, since the broker has to get to them through the guest network?

Measure twice, poll once.

Posted February 2, 2026 at 2:09 pm · in JSN-SR04T waterproof ultrasonic on a Pi 3 gives 0 cm or timeouts for our hostel water tank #6

Maybe add a time.sleep(0.5) between readings? I read they need time to settle.

Measure twice, poll once.

Posted February 1, 2026 at 3:57 pm · in What are the empty holes next to the GPIO header on an old Pi model B? #2

I think those are for the camera?

Measure twice, poll once.

Posted January 15, 2026 at 10:01 pm · in Old 8-bit PIC with no SPI peripheral: can it drive an SX1276 for LoRaWAN? #2

Could you use a LoRa module that runs the stack itself and just talk to it over UART with AT commands?

Measure twice, poll once.

Posted December 15, 2025 at 2:50 am · in Uploading to a Nano through an HC-05 fails with stk500_getsync not in sync #5

Did you pick the right board and processor? Old Nanos need “ATmega328P (Old Bootloader)”.

Measure twice, poll once.

Posted November 30, 2025 at 12:32 am · in STM32 with a MAX3485 gets my own echo and loses the start of the Modbus reply #3

Maybe a baud rate mismatch between the two?

Measure twice, poll once.

Posted October 28, 2025 at 2:58 am · in Vendor quote says ‘Bluetooth 4.0’ sensors, another one says ‘BLE’. Same thing? Will either work with Hermetry? #3

I think 4.0 is the version number and BLE is part of it? Not sure though.

Measure twice, poll once.

Posted October 26, 2025 at 1:51 pm · in Live view of a camera 180 m from the building on our dashboard #2

Couldn’t you use Wi-Fi for the camera? 180 m is far but with a good antenna maybe.

Measure twice, poll once.

dev_kevin

Forum Replies Created