QR Generator — How-To Guide

Prerequisites: Setup complete (see SETUP.md). qrcode[pil] installed.

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Table of Contents

1. How to Create a URL QR Code
2. How to Create a WiFi QR Code for Guests
3. How to Create a Contact (vCard) QR Code
4. How to Create a Phone or SMS QR Code
5. How to Create an Email QR Code
6. Automating with Cron
7. Combining with Other Skills
8. Troubleshooting Common Issues
9. Tips & Best Practices

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1. How to Create a URL QR Code

What this does: Generates a PNG image containing a QR code that opens a URL when scanned.

When to use it: Adding a QR code to a flyer, business card, poster, or email that links to your website, event page, or any URL.

Steps

Step 1 — Navigate to the skill directory.

cd ~/smfworks-skills/skills/qr-generator

Step 2 — Run the url command with your URL and desired output filename.

python3 main.py url https://mycompany.com ~/Desktop/website-qr.png

Output:

✅ QR code generated: /home/user/Desktop/website-qr.png
   Data: https://mycompany.com
   Size: 25x25

Step 3 — Verify by scanning.
Open ~/Desktop/website-qr.png in an image viewer, then scan it with your phone's camera. It should navigate to your URL.

Step 4 — Include in your design.
The PNG file is ready to insert into Canva, Word, Photoshop, or any design tool.

Result: A website-qr.png file at ~/Desktop ready to use in any design or printout.

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2. How to Create a WiFi QR Code for Guests

What this does: Encodes your WiFi credentials into a QR code. When a guest scans it, their phone connects to your network immediately — no typing required.

When to use it: Home, Airbnb, cafe, office, or any location where you want guests to connect quickly without reading out a password.

Steps

Step 1 — Navigate to the skill directory.

cd ~/smfworks-skills/skills/qr-generator

Step 2 — Create the WiFi QR code.
Replace GuestNetwork with your network name and welcome2024 with your actual password.

python3 main.py wifi 'GuestNetwork' 'welcome2024' ~/Desktop/guest-wifi.png

Output:

✅ WiFi QR code generated: /home/user/Desktop/guest-wifi.png
   Network: GuestNetwork
   Size: 33x33

Step 3 — Test it yourself.
Scan the PNG with your own phone to verify it connects to the right network.

Step 4 — Print and display it.
Print the PNG at any standard size (4x4 inches is easy to scan). Frame it or laminate it near your router.

Result: A printable WiFi QR code that guests can scan to connect without you spelling out your password.

Security note: Only put WiFi QR codes in private or semi-private locations. Anyone who photographs the printed code can use it to connect.

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3. How to Create a Contact (vCard) QR Code

What this does: Encodes a contact card — name, phone number, and optionally email — into a QR code. Scanning it prompts the phone to add the contact directly.

When to use it: Business cards, name badges, conference booths, or email signatures where you want people to save your contact with one scan.

Steps

Step 1 — Navigate to the skill directory.

cd ~/smfworks-skills/skills/qr-generator

Step 2 — Generate the vCard QR code.

python3 main.py vcard 'Jane Smith' '+1 415 555 0001' 'jane@mycompany.com' ~/Desktop/jane-contact.png

Output:

✅ vCard QR code generated: /home/user/Desktop/jane-contact.png
   Name: Jane Smith

Step 3 — Test the contact scan.
Open the PNG and scan it with your phone. You should see a contact prompt with Jane's name, phone, and email.

Step 4 — Add to your business card or email signature.
Include the PNG in your business card design, or embed it in a Canva/Word template.

Result: Anyone who scans your QR code immediately gets a prompt to save your contact info — no typing, no typos.

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4. How to Create a Phone or SMS QR Code

What this does: phone creates a QR that initiates a call. sms creates a QR that opens a pre-addressed text message (with optional pre-filled text).

When to use it: Customer service signs, storefront displays, or any place where you want people to reach you with one scan.

Steps — Phone QR

Step 1 — Navigate to the skill directory.

cd ~/smfworks-skills/skills/qr-generator

Step 2 — Generate a call QR code.

python3 main.py phone '+12125550001' ~/Desktop/call-us.png

Output:

✅ Phone QR code generated: /home/user/Desktop/call-us.png
   Phone: +12125550001

Scanning this opens the phone dialer with your number pre-entered.

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Steps — SMS QR

Step 1 — Generate an SMS QR code with a pre-filled message.

python3 main.py sms '+12125550001' 'Hi, I have a question about your product.' ~/Desktop/text-us.png

Output:

✅ SMS QR code generated: /home/user/Desktop/text-us.png
   Phone: +12125550001

Step 2 — Test it.
Scan with your phone — it should open Messages (or your default SMS app) with the number pre-filled and the message already typed.

Result: A QR code for instant phone or SMS contact.

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5. How to Create an Email QR Code

What this does: Generates a QR code that opens a new email pre-addressed to a specific email address.

When to use it: Conference badges, contact forms on printed materials, "email us" QR codes on packaging.

Steps

Step 1 — Navigate to the skill directory.

cd ~/smfworks-skills/skills/qr-generator

Step 2 — Generate the email QR.

python3 main.py email support@mycompany.com ~/Desktop/email-us.png

Output:

✅ Email QR code generated: /home/user/Desktop/email-us.png
   Email: support@mycompany.com

Step 3 — Verify by scanning.
Should open your phone's email app with support@mycompany.com in the To field.

Result: A QR code that lets anyone send you an email with a single scan.

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6. Automating with Cron

You can schedule QR code generation automatically — for example, regenerating a QR code each month if your URL changes (like a monthly calendar link).

Open the cron editor

crontab -e

Example: Regenerate a monthly link QR code on the 1st

0 8 1 * * python3 /home/yourname/smfworks-skills/skills/qr-generator/main.py url "https://mycompany.com/calendar/$(date +\%Y-\%m)" /home/yourname/Desktop/monthly-qr.png >> /home/yourname/logs/qr-generator.log 2>&1

Cron Expression Reference

Expression	Meaning
0 8 1 * *	First day of each month at 8 AM
0 9 * * 1	Every Monday at 9 AM
0 7 * * *	Every day at 7 AM

Create the log directory

mkdir -p ~/logs

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7. Combining with Other Skills

QR Generator + File Organizer: Generate multiple QR codes and then organize them by date:

python3 ~/smfworks-skills/skills/qr-generator/main.py url https://event1.com ~/QR-codes/event1.png
python3 ~/smfworks-skills/skills/qr-generator/main.py url https://event2.com ~/QR-codes/event2.png
python3 ~/smfworks-skills/skills/file-organizer/main.py organize-date ~/QR-codes/

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8. Troubleshooting Common Issues

qrcode not installed. Run: pip install qrcode[pil]

The package is missing.
Fix: pip install "qrcode[pil]" (quotes are important in some shells).

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Error: Data too long (max 2000 characters)

Your URL or data exceeds 2,000 characters.
Fix: Use a URL shortener (bit.ly, tinyurl.com) to shorten the URL before passing it to the command.

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Error: Data contains invalid characters

Your input contains shell special characters (;, |, &, $, newlines).
Fix: Use single quotes around arguments: python3 main.py wifi 'My;Network' 'pass&word'

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Error: Only http, https, mailto, and tel URLs are allowed

You used a URL scheme other than the four supported ones.
Fix: Only http://, https://, mailto:, and tel: are accepted. For other schemes, use the url command with the data as text.

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Error: Phone number contains invalid characters

The phone number has letters or symbols other than +, -, spaces, and parentheses.
Fix: Strip non-numeric characters: +1 (212) 555-1234 is fine; extension:4 is not.

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The QR code won't scan

Possible causes: the image is too small when printed, or the error correction level isn't enough for the print quality.
Fix: Print at least 2×2 cm. Ensure good contrast (black on white). If scanning from a screen, try zooming in on the image.

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9. Tips & Best Practices

Use single quotes for arguments with spaces or special characters. python3 main.py wifi 'My Network' 'p@ssw0rd' — double quotes work too, but single quotes are safer for special characters.

Always test by scanning before printing. Generate the QR, scan it on your phone, confirm it does what you expect. Printing and distributing an untested QR code is a common mistake.

For WiFi QR codes, print large enough to scan from a comfortable distance. 3–4 inches square is ideal for wall-mounted use.

For business card QR codes, use vcard not url. The vCard format prompts the phone to add a contact, which is more useful than just opening a website.

For URL QR codes, prefer short URLs. Shorter URLs produce smaller QR codes with fewer dots, making them easier to scan at small sizes. Use a URL shortener for long links.

PNG works for most uses; SVG is better for print design. PNGs can get pixelated when scaled up. If you're inserting the QR code into a design that might be resized, use .svg output:

python3 main.py url https://mysite.com mysite-qr.svg

Store your QR codes in a named folder. If you generate QR codes regularly, keep them organized:

mkdir -p ~/QR-codes
python3 main.py wifi 'HomeNet' 'pass123' ~/QR-codes/home-wifi.png