{"product_id":"qr-code-participant-check-in-with-n8n-google-sheets-slack","title":"QR Code Participant Check-In with n8n, Google Sheets \u0026 Slack","description":"\u003ch3\u003eInstant QR check-in that logs attendance to Google Sheets—and prevents duplicate scans\u003c\/h3\u003e\n\u003cp\u003eThis n8n workflow turns a QR code into a fast participant check-in kiosk. It records attendance in \u003cstrong\u003eGoogle Sheets\u003c\/strong\u003e, stops the same person from scanning twice using an \u003cstrong\u003en8n Data Table\u003c\/strong\u003e, calculates progress toward a required attendance threshold, and sends \u003cstrong\u003eSlack alerts\u003c\/strong\u003e when certification becomes mathematically unreachable.\u003c\/p\u003e\n\n\u003ch3\u003eWhat this workflow does\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eQR-driven submission via n8n Form:\u003c\/strong\u003e Participants enter their email while the \u003cem\u003esession code\u003c\/em\u003e is automatically prefilled from the QR link.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNormalize + build a composite check-in key:\u003c\/strong\u003e The workflow normalizes the email, reads workflow settings (Sheet ID, tab names, Slack channel, threshold), and combines \u003cstrong\u003eemail + session code\u003c\/strong\u003e into a unique key.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDeduplicate with n8n Data Table:\u003c\/strong\u003e Before logging, it checks the Data Table for the composite key. If it already exists, the participant sees an \u003cstrong\u003e“Already checked in”\u003c\/strong\u003e completion screen and no duplicate is recorded.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLog to Google Sheets:\u003c\/strong\u003e For first-time scans, it looks up the participant in a Google Sheets roster and appends a timestamped check-in to the \u003cstrong\u003eCheck-Ins\u003c\/strong\u003e tab. Unregistered attendees are tagged as \u003cstrong\u003eWALK_IN\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTrack progress and compute attendance %:\u003c\/strong\u003e It reads required sessions from a schedule tab, pulls historical check-ins from the Data Table, and calculates both \u003cstrong\u003ecurrent\u003c\/strong\u003e and \u003cstrong\u003ebest-case\u003c\/strong\u003e attendance percentages against the threshold.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSlack at-risk alert + participant confirmation:\u003c\/strong\u003e If the threshold is unreachable even with perfect future attendance, it posts an at-risk alert to a Slack channel, then shows the participant a completion screen.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eUse cases\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eTraining cohorts that require a minimum attendance percentage for certification.\u003c\/li\u003e\n  \u003cli\u003eEvent staff want QR kiosk check-in with automatic walk-in detection.\u003c\/li\u003e\n  \u003cli\u003eOrganizations need duplicate scan prevention and real-time coordinator notifications.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical details\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003en8n nodes:\u003c\/strong\u003e if, set, code, form, slack, data table\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIntegrations:\u003c\/strong\u003e n8n Form (check-in submission), \u003cstrong\u003eGoogle Sheets\u003c\/strong\u003e (roster, Check-Ins, schedule), \u003cstrong\u003eSlack\u003c\/strong\u003e (at-risk alerts)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCore logic:\u003c\/strong\u003e composite key (email + session code) + Data Table deduplication + threshold reachability calculation\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"N8N Commerce","offers":[{"title":"Default Title","offer_id":45814429679795,"sku":"N8N-17985","price":39.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0749\/6279\/6723\/files\/ilEd95fU7hg7P0icPzK_w2hdXRhb.png?v=1786439893","url":"https:\/\/buyflowscripts.com\/products\/qr-code-participant-check-in-with-n8n-google-sheets-slack","provider":"N8N Commerce","version":"1.0","type":"link"}