Choosing hardware for a walk-in health centre check-in

Annual energy = watts × 12 h × 365 / 1000 × £0.28. Refurbished PC: 120 W gives 525.6 kWh, £147.17 per kiosk, £883.02 for six, £4,415 over five years; purchase 6 × £180 = £1,080; five-year total £5,495. Raspberry Pi: 12 W gives 52.56 kWh, £14.72 per kiosk, £88.30 for six, £441.50 over five years; purchase £660; total £1,101.50. Thin client: 10 W gives 43.8 kWh, £12.26 per kiosk, £73.60 for six, £368 over five years; purchase £1,320 + £3,800 server = £5,120; total £5,488. The Pi is by far the cheapest to buy and run, but cost is not the only criterion. The thin-client total is almost the same as refurbished PCs, and its server is a single point of failure: if the VDI server or network fails, all six kiosks fail, which conflicts with the 15-minute-per-week downtime limit. Refurbished PCs run locally and support USB wristband printers directly; adding a 240 GB SSD (£35 each, £210 total) gives a five-year total of £5,705. Recommendation: buy refurbished PCs with SSDs, clean them monthly, and replace hard disks before deployment. If the centre already has a resilient server room and a managed network with redundant links, thin clients become the better choice because they produce less heat and are centrally updated.

First, the microSD card is the boot disk and is repeatedly written by logs, PDF forms and browser caches. MicroSD cards have limited write endurance and can corrupt on sudden power loss, which is likely in a health centre; one corrupted card means a kiosk is down until someone reimages it, likely more than 15 minutes. Second, the Pi 5 throttles when its system-on-chip reaches high temperatures. At 32 °C ambient, with dust and a sealed kiosk enclosure, sustained browser and PDF work can push it into thermal throttling, making the touch interface slow and increasing support calls. Third, USB wristband printing may need proprietary drivers that are not available for the Pi's ARM build; a workaround through a print server adds a network dependency. These are not fatal in a hobby project, but they are reliability risks against a 15-minute target. A fan, industrial-grade SD card or SSD, and a managed print queue would reduce the risk, but they add cost and support effort.

RAM affects how many things the kiosk can hold in memory at once: browser, PDF viewer, print spooler, and the check-in web app. With 4 GB, opening a large PDF while the browser has several tabs can force paging to disk; on a hard disk, paging is slow and the touchscreen appears frozen during check-in. 8 GB reduces paging and allows the OS to cache the app, so the first check-in after boot is faster. Storage type affects both boot time and failure mode. A hard disk takes tens of seconds to spin up and seeks randomly; an SSD boots in seconds and has no moving parts, so it tolerates the dust and vibration of a kiosk. A microSD card is cheap but has poor random-write endurance and no power-loss protection. For a five-year, 12-hour-a-day kiosk, an SSD with wear monitoring is the safer choice; RAM should be at least 8 GB if the PDF forms are large, but 4 GB can work if the browser is locked to one page and the PDFs are kept small.