Building an IOT Notification Device From Scratch

Posted3 months agoActive3 months ago

bertwagner

86 points

18 comments

bertwagner.comTechstory

supportivepositive

Debate

20/100

IOTEsp32Home Automation

Key topics

IOT

Esp32

Home Automation

The author shares their project of building an IoT notification device from scratch to notify them when their kids need to get out of the pool, sparking discussion on the ESP ecosystem and potential improvements.

Snapshot generated from the HN discussion

Discussion Activity

Moderate engagement

First comment

23s

Peak period

0-3h

Avg / period

3.6

Comment distribution18 data points

Loading chart...

Based on 18 loaded comments

Key moments

01Story posted
Oct 1, 2025 at 8:43 AM EDT
3 months ago
Step 01
02First comment
Oct 1, 2025 at 8:44 AM EDT
23s after posting
Step 02
03Peak activity
9 comments in 0-3h
Hottest window of the conversation
Step 03
04Latest activity
Oct 3, 2025 at 11:42 AM EDT
3 months ago
Step 04

Generating AI Summary...

Analyzing up to 500 comments to identify key contributors and discussion patterns

Discussion (18 comments)

Showing 18 comments

bertwagnerAuthor

3 months ago

2 replies

Author here. Thanks for reading. This was a massive learning project for me, I'm happy to answer questions or feedback.

cstuder

3 months ago

1 reply

FYI: A couple of the images down in the article are not loading (And later some seem to be incorrectly formatted). I'm especially looking forward to the exploded button.

bertwagnerAuthor

3 months ago

1 reply

D'oh. Thank you for letting me know. All fixed now. Hopefully "exploded button" wasn't too misleading (more of an exploded view of the design).

auspiv

3 months ago

2 replies

bro your images are giant. every load of the page is transferring 40ish MB. back_panel_back_render.png is 11.3 MB. replace those with smaller versions and click to link to the larger.. but I do see both cloudfront and cloudflare headers so not sure why these aren't being cached by them

bertwagnerAuthor

3 months ago

1 reply

Thanks for letting me know, I will have to fix this soon. This was the first post as part of a new blogging setup I'm using and clearly I'm missing some of my old processes (like image resizing).

hnuser123456

3 months ago

They are photographic images saved as PNG, which is lossless and intended for digitally created images with large areas of pixels with the exact same value. Please use a format intended for photographic images. Splashflag.png is 4.5 MB, it's 10.5 MB as an uncompressed BMP file, but only 600 KB as a JPEG with indistinguishable quality loss.

01HNNWZ0MV43FF

3 months ago

They probably need the origin server to set the right cache headers, otherwise the cdn would get blamed for stale images

sleepybrett

3 months ago

Almost Name Twin here (brett wagner) just saying hey.

Havoc

3 months ago

2 replies

The entire ESP ecosystem is quite accessible for people of modest technical ability.

HomeAssistant+ ESPHome + ESP32 in particular is a good stack because it takes away most of the complexity. Common sensors have ESPHome code available with a quick google so just need to connect the wires right basically

NoiseBert69

3 months ago

1 reply

Problem is that ESP32s are super power hungry once you start using BLE or Wifi.

For BLE you can use STM32s and Nordics. But Wifi-on-Chip is ESP32-only.

aksss

3 months ago

BLE and WiFi are power hungry on any platform. LoRaWAN or zigbee are better for low power, low bw comms. Kinda sacrifice simplicity & ubiquity of support in that you need a gateway/router of some sort, but they are solid solutions with long range and high penetration.

mlhpdx

3 months ago

Indeed about ESP32 being approachable. I particularly enjoyed finding and messing about with the Cheap Yellow Display. It’s a fun little platform and with LVGL making it pretty is a joy.

Would have been a nicer fit (smaller bevel) than the LCD in this project at about the same cost.

mlhpdx

3 months ago

2 replies

If you want to avoid “long polling” then MQTT isn’t the answer (it’s still a long held TCP connection waiting for messages). UDP would be the way to go, and with WireGuard as a carrier you don’t have to worry about NAT traversal issues (and get privacy as a bonus).

Love the project - would have been great when my kiddos were that age.

bertwagnerAuthor

3 months ago

Thank you and I'm glad you enjoy the project. I'll have to look more into UDP for this type of solution.

jkscm

3 months ago

MQTT is not the same as long polling

petesoper

3 months ago

When I got to auto[ssid, etc in main.c it became clear the sophistication/excursion from the typical Esp32 code centerline is at many levels. Thanks for sharing!

mxuribe

3 months ago

This is wonderful! Thanks for sharing!!

9029

3 months ago

Very cool project, I feel inspired to try something like this myself!

I noticed there seems to be a use-after-return with the creds returned from CredentialManager::retrieveCredentials (C-arrays can't be passed/returned by value). One solution could be to return Arduino Strings instead

View full discussion on Hacker News

ID: 45437027Type: storyLast synced: 11/20/2025, 12:47:39 PM

Want the full context?

Jump to the original sources

Read the primary article or dive into the live Hacker News thread when you're ready.

Open link View on HN