How NeutroTV works

The player is a Raspberry Pi (the Zero 2 W is the standard pilot unit) with an SD card flashed with the NeutroTV image, an official power supply and an HDMI cable to the TV. It boots in about a minute and a half. We ask installers to power it from a wall supply, never from the TV's USB port, because many TVs cut USB power in standby.

Two TV settings matter and are on the install checklist: turn off the TV's overscan ("Fit to Screen", "Just Scan", "Dot by Dot" depending on the brand) so the edges of your signs are not cropped, and set the TV's sleep and eco timers so it does not switch itself off during store hours.

When the box finds no internet at boot it shows a WiFi Setup screen and opens a temporary open hotspot called NeutroTV-Setup. Join it from a phone, scan the QR code on the TV (it points at the box's own setup page), pick the store network from the list and enter the password. The box drops the hotspot, joins the network and waits for internet. If the password was wrong, the hotspot simply comes back so you can try again. The saved network is kept on the data partition and survives reboots and updates. A 2.4 GHz network is required.

Once online, the TV shows Pair This Device with a six-character code and a QR code. Scanning it opens app.neutrotv.com/activate with the code filled in. Sign in, name the screen, and within seconds the TV shows your store logo and the screen appears on your dashboard. If that Pi was paired before — say you replaced its SD card — it re-pairs to the same screen automatically.

On the Content page, either upload pictures, videos and PDFs, or pick a template and type in the text and prices; your logo and colours are already applied. Put signs into a group (a loop) and set how long each shows. On the Schedule page add a time block: which group, which days, from when until when. The fastest path is the Home page button Put something on a screen.

An online player asks the cloud every 30 seconds whether its schedule ("manifest") has changed. When it has, the player downloads any new files first, then switches to the new schedule in one step and keeps the previous one on disk. Because files are addressed by content hash, a sign used in three groups is downloaded once.

Nothing on the TV changes. The player keeps evaluating its local schedule in the store's time zone, so time blocks still switch at the right hour. It retries the connection with increasing intervals and returns to normal the moment one attempt works, downloading whatever changed in the meantime. On the dashboard the screen shows "hasn't checked in" after two minutes and is marked offline after five, with an optional email alert. Customers keep seeing signs the whole time.

There is a detailed runbook for store managers covering what to check, what not to do (for example, do not pull the power during an update), and how to re-provision Wi-Fi if the store's network or password changes.

Player software updates are small and applied in place with a backup. Full system updates use two root partitions: the new image is written to the inactive one and booted exactly once as a trial. About two minutes in, a health check on the box confirms networking, the display engine, the player and the API are all working; only then is the new slot made permanent. If the trial does not boot, the firmware falls back to the proven slot on its own; if the health check fails, the box reboots into the proven slot. In either case the screen comes back on the version that was working before.