Rugged Metal Buttons with LED Rings on Raspberry Pi

How to interface rugged metal pushbuttons with LED rings to a headless Raspberry Pi — using the built-in triggerhappy daemon to invoke scripts on button press and provide LED feedback, with no display or keyboard needed.

Connection diagram — two pushbuttons wired to Raspberry Pi GPIO pins.

How it works

Instead of userspace I/O libraries, this approach uses the triggerhappy daemon (built into Raspbian) to map standard key codes from /dev/input/eventX to scripts via /etc/triggerhappy/triggers.d/actions.conf.

Overview of the steps:

1. Connect pushbuttons to Raspberry Pi GPIOs as shown in the connection diagram
2. Prepare a Raspberry Pi OS Lite SD card using Raspberry Pi Imager
3. SSH into the Raspberry Pi
4. Add dtoverlay config lines to /boot/config
5. Create push-buttons.conf under /etc/triggerhappy/triggers.d/
6. Modify /lib/systemd/system/triggerhappy.service to run as the pi user
7. Create action scripts configured in push-buttons.conf
8. Reboot and press a button to see the configured action invoked

Prepare the SD card

1. Download the Raspberry Pi Imager
2. Open the app → CHOOSE OS → Raspberry Pi OS (Other) → Raspberry Pi OS Lite (32-bit)
3. Insert the SD card and click CHOOSE STORAGE
4. Press Ctrl + Shift + X to open advanced options
5. Set hostname, enable SSH, username/password, and local time settings as shown below, then click SAVE
6. Click WRITE to create the bootable SD card

Raspberry Pi Imager — advanced options for headless setup.

Setup and demo

1. Connect two pushbuttons to Raspberry Pi GPIO pins as shown in the connection diagram
2. Insert the SD card, connect the Pi to your local DHCP network, and power on
3. SSH in: ssh pi@my-raspi-001 (use the password from the Imager advanced options)
4. Run the following commands:

sudo apt-get install -y git esptool
git clone https://github.com/hackboxguy/pi-pushbtn-demo.git
cd pi-pushbtn-demo
sudo ./setup.sh
sudo reboot

Running the setup commands on the Raspberry Pi.

Wait ~40 seconds for the Pi to reboot. Press one pushbutton — its LED ring blinks at ~2 Hz. Press the other button — its LED starts blinking and the first one stops.

Extending the demo

Instead of just blinking LEDs, the buttons can invoke real tasks. For example, to flash different firmware binaries to an ESP8266 (e.g. Wemos D1 Mini) on button press, replace the action scripts:

cp /home/pi/pi-pushbtn-demo/flash-esp-1hz.sh /home/pi/pi-pushbtn-demo/key-pressed-down.sh
cp /home/pi/pi-pushbtn-demo/flash-esp-4hz.sh /home/pi/pi-pushbtn-demo/key-pressed-up.sh

After this change, pressing a button blinks the LED ring for ~30 seconds (indicating the Wemos D1 Mini is being flashed), then stops when flashing completes. See the 1 Hz flash script and 4 Hz flash script for details.

Complete setup — rugged metal pushbuttons connected to the Raspberry Pi.

SOURCE CODE

github.com/hackboxguy/pi-pushbtn-demo — scripts and setup instructions

Related posts

• OpenUI: IR Remote, LCD & I2C for Headless Linux
• YARMP: Lightweight Raspberry Pi Media Player
• DIY Passive PoE for Raspberry Pi Under $2

Bridge SMS to XMPP: Receive 2FA Codes Abroad

Bridge your mobile SMS with XMPP instant messaging so you can read and send text messages from anywhere over the internet. The primary use case: receiving 2FA verification codes while travelling internationally, without roaming or asking someone at home to read them out for you.

Setup overview — a Raspberry Pi with a USB 3G modem bridges SMS to XMPP via a public Jabber server.

The setup uses a Raspberry Pi with a Huawei E173 (or E303) USB 3G dongle and an encrypted XMPP connection to deliver SMS securely to your phone's chat app. All code is open source, and you can use any public Jabber server (or host your own with Prosody).

Preparing the SD card

1. Download the Raspberry Pi Imager
2. Open it and select: CHOOSE OS → Raspberry Pi OS (Other) → Raspberry Pi OS Lite (32-bit)
3. Select your SD card via CHOOSE STORAGE
4. Press Ctrl + Shift + X to open the advanced options
5. Set hostname, enable SSH, username, password, and timezone as shown below, then click SAVE
6. Click WRITE to create the bootable SD card

Raspberry Pi Imager — advanced options for hostname, SSH, and credentials.

Setting up the Raspberry Pi

1. Insert your SIM card (PIN lock must be disabled) into the Huawei E173/E303 dongle and connect it to the Raspberry Pi
2. Keep the Pi powered on and connected to your home internet 24/7
3. Once booted, SSH in:

ssh pi@my-raspi-001

4. Install the XMPP remote agent:

sudo apt-get install -y git
git clone --recursive https://github.com/hackboxguy/xmpp-remote-agent.git
cd xmpp-remote-agent
./setup.sh -u raspi-sim-1@jabber.de -p my-raspi-xmpp-secret-pw
sudo reboot; exit

Replace the example XMPP username and password with your own credentials.

The setup.sh script may take 10–15 minutes on a Raspberry Pi 1.

On your phone's Xabber app (Android or iOS), log in with your XMPP account (e.g. john.doe@jabber.de). The Raspberry Pi should appear online — send help to get the list of available commands.

Reading SMS

smsupdate       # fetch SMS from SIM to cache (wait for Success response)
smstotal        # show number of cached messages
smsget 0        # read the first message

Sending SMS

smssend +919876543210 this is a test message

Deleting SMS

When the SIM memory is full, new messages stop arriving. Delete all stored messages with:

smsdeleteall

Voice dialling and USSD codes

Ring a GSM phone (caller ID shows as SIM-1's number, no audio — ringing only):

dialvoice +919876543210

Check prepaid balance or send other USSD codes:

dialussd *100#     # send USSD code (wait for Success response)
readussd           # read the carrier's response

How it works internally

Two services run on the Raspberry Pi:

• bboxsmsrv — based on libgammu, handles SMS read/write/delete via the USB 3G modem
• xmproxysrv — based on libgloox, acts as a headless XMPP client that logs into the Jabber server and maintains an always-on connection

When a 2FA SMS arrives, it is stored in the SIM memory by the 3G modem. On your phone's Xabber app, you send smsupdate → xmproxysrv parses the command and asks bboxsmsrv to fetch messages from the SIM → once complete, a Success response is sent back → you then read the messages with smsget.

For sending, the flow reverses: your chat message travels through the XMPP server to xmproxysrv, which hands it to bboxsmsrv, which sends the SMS via the 3G modem — delivering an SMS to any phone number without roaming charges.

SOURCE CODE

github.com/hackboxguy/xmpp-remote-agent — setup scripts and configuration

github.com/hackboxguy/brbox — bboxsmsrv and xmproxysrv sources

Related posts

• Remote GSM SIM Management with Raspberry Pi
• XMPP Account Setup Guide for IoT Remote Control
• Access Your Raspberry Pi Remotely via XMPP Chat

$30 Pocket Router as an AWS IoT Edge Device

How to flash a ~$30 GL.iNet MT300N-V2 pocket router with a custom OpenWrt image that includes the AWS IoT Device SDK and an aws-iot-pubsub-demo application — turning it into an AWS IoT Edge device that can feed local sensor data to the cloud.

GL.iNet MT300N-V2 pocket router — ready to become an AWS IoT Edge device.

Quick overview

Three steps to turn your pocket router into an AWS IoT Edge device:

1. Flash the OEM firmware with the custom gl-mt300nv2-awsiot-demo.bin
2. Upload your AWS-generated device certificate and private key via the web UI
3. Reboot and watch Hello World messages published to your AWS IoT Core

Flashing the firmware

Step 1 — Connect your PC to the pocket router via Ethernet and power it on. Wait for the LED to stop blinking.

Setup: PC connected to the pocket router via Ethernet cable.

Step 2 — Open http://192.168.8.1/cgi-bin/luci/admin/system/flashops in your browser (or follow GL.iNet's onboarding process).

Step 3 — Find the firmware upgrade menu and flash with gl-mt300nv2-awsiot-demo.bin.

Important: Disable "Keep settings" — you want to start with default settings.

Step 4 — Wait about 2 minutes until the LEDs stop blinking.

Step 5 — Disconnect and reconnect the Ethernet cable on your PC so it gets a new IP in the 192.168.20.x range.

Step 6 — Navigate to http://192.168.20.1 — you should see the new web UI:

Custom firmware web UI after successful flash.

AWS IoT configuration

Step 7 — Upload your device certificate and private key files through the web UI:

Upload your AWS-generated device certificate and private key.

Step 8 — Go to AWS-IoT → Service Settings, enter your endpoint, and click Save & Apply.

Before clicking Save & Apply, ensure your security policies on console.aws.amazon.com are set up correctly (see Step 10 below).

Service Settings — enter your AWS IoT endpoint here.

Step 9 — Check the Service Log. If everything is configured correctly, you should see a "connection success" message:

Service Log — "connection success" confirms the router is connected to AWS IoT Core.

Step 10 — On console.aws.amazon.com, ensure your security policies are set correctly:

AWS IoT security policies — required permissions for the device.

Testing publish and subscribe

Step 11 — On console.aws.amazon.com, subscribe to topic test/topic to see Hello World messages published from your pocket router. By default, the demo publishes 10 messages at 5-second intervals. To publish continuously, increase the Publish Count in the Service Settings page.

AWS IoT Core — Hello World messages arriving from the pocket router.

Step 12 — To test the subscribe action, publish a JSON message to topic test/topic_led from the AWS console to control the router's LED:

{"powerstate" : "on"}
{"powerstate" : "off"}

Publishing LED control commands from the AWS IoT console.

Other use cases

The pocket router can act as a gateway between AWS IoT Core and local Wi-Fi or USB-connected devices:

Possible use cases — the pocket router bridges local devices to AWS IoT Core.

SOURCE CODE

github.com/hackboxguy/openwrt-wrapper — build instructions and sources

gl-mt300nv2-awsiot-demo.bin — pre-built firmware image

Related posts

• Getting Started with AWS IoT on OpenWrt Routers
• Remote-Kit: Pocket Router for Remote Hardware Bring-up
• AWS IoT on Raspberry Pi with 25 MB Buildroot Linux