Set up the Presto

The Presto ships with MicroPython and a launcher already on it. You add one app to it, tell the app where your daemon is, and give it your Wi-Fi credentials.

The guided setup

This is the normal route, and it needs no copy of this repository. The daemon's admin page prepares the exact app its running build expects, so a Presto installed this way matches the daemon from the first poll.

You need:

• the daemon installed and running, from PyPI/pipx or Docker, anywhere on your network;
• the Presto, plugged into a Windows, macOS or Linux computer by a data-capable USB cable;
• Python 3 on that computer. The setup script needs two packages (cryptography and mpremote). If they are missing, it offers to install them into a private, temporary environment, which it deletes when it finishes; answer Y. pipx run presto_setup.py and uv run presto_setup.py do the same without asking.

One process for every case

Setting up, re-initialising, changing the Wi-Fi and moving a Presto to another daemon all use the same two steps: prepare a download on the admin page of the daemon the Presto should use, then run the script it gives you on the USB computer. The script looks at the Presto and does what is needed.

You want to	What to do
Set up a new Presto	The steps below
Re-initialise a Presto	The same steps. A re-initialised Presto gets a new device identifier, so the old record stays listed as offline in Presto devices on the daemon's Status tab: open it and press Remove this record
Change the Wi-Fi network or password	The same steps, with Set the Wi-Fi network on the Presto ticked
Move a Presto to a new daemon (the database and settings stay where they are)	The same steps on the new daemon's admin page; the script changes only the daemon address and token

Every run leaves the Presto updating its app over the air. The script installs the app twice, in two app slots, with a small bootstrap that starts one and falls back to the other if a new version fails. It also gives the Presto the daemon's update certificate, so later app updates arrive from the daemon with no cable. USB is only needed again to recover a Presto, to move it to another daemon, or after a firmware update (see If something goes wrong).

• A new Presto gets the app, its settings and the update certificate.
• A Presto set up before over-the-air updates existed (the app as /ai_dash.py and /ai_dash_files) is moved to the new layout. Its settings, name and device identifier stay; the old app files are removed only after the new ones have verified.
• A Presto that already updates over the air is reinstalled, which is also how one is repaired, and its settings stay.

The app takes about 650 KiB, a minute or two to copy over USB.

1. Open the admin page and choose Set up a Presto

Open the daemon's admin page and unlock it with the admin token. On the Settings tab, open Set up a Presto.

2. Confirm the address the Presto can reach

The page suggests addresses it knows about. Use the daemon computer's LAN address, such as 192.168.1.50, and the daemon's device port (8787 by default).

• Never localhost or 127.0.0.1: that is the Presto's own address, not the daemon's.
• Docker: do not use a container-internal address. Use the host's LAN address and the port the Compose file publishes.
• A container on a remote server: the Presto contacts the server over your network. Nothing about the container is involved in the USB setup.

Set the Wi-Fi network on the Presto is ticked by default, and should stay ticked: without a Wi-Fi network the Presto cannot reach the daemon, show anything or be updated. Untick it only for a Presto that already joins your network (it was set up before, or another Pimoroni app uses it). The page then shows an amber Wi-Fi is needed note, and the setup script keeps the Wi-Fi already on the Presto and never asks for a password. If the Presto turns out to have none, the script stops before writing anything and tells you to prepare the download again with the box ticked.

Press Prepare download. The button goes away, your browser downloads both files by itself, and the page shows:

• a setup unlock code with a Copy button;
• links to presto_setup.py, the standalone installer with this build's app files, and presto_setup.enc, the encrypted configuration for this handoff, in case your browser blocked one. A browser may ask once whether to allow several downloads: allow it.

Your browser may warn about presto_setup.py. Edge, Chrome and others say something like "presto_setup.py could harm your device. Do you want to keep it anyway?", because it is a program file. That is expected: choose Keep. The file is plain Python text you can open and read before you run it. It holds no password or token, because those are in presto_setup.enc, which only the unlock code opens. Keep it only if you pressed Prepare download a moment ago; if you did not, delete it.

To prepare another download, press Prepare another download. It uses the settings in the form above it, so change them there first if you want different ones. The new unlock code replaces the old one.

The code is deliberately not inside either file. It is shown once; if you lose it, prepare a new download. The encrypted file holds the daemon address, the app revision and the persistent shared device token, so treat it as sensitive and delete it when setup is done.

3. Run the setup script on the USB computer

Put both files in one folder on the computer the Presto is plugged into, open a terminal there, and run:

python presto_setup.py

On macOS or Linux, use python3 if that is how Python 3 is named. The script:

1. asks for the unlock code and decrypts the setup file in memory. The code is not shown as you type: each character, including each one of a paste, appears as a *, so you can tell the paste worked. Nothing is written to the device, and no temporary plaintext file is created on the computer; then it checks that the daemon answers at the address in the file from this computer, before opening the USB device. A typo, a daemon that is not running or a wrong port stops it here with nothing touched;
2. finds the USB serial device. If exactly one is connected it uses that one and says so; if there are several it lists them and asks you to choose by number, because it never guesses between boards;
3. checks that the device is a Pimoroni Presto before writing anything, and stops if it is not;
4. asks for your Wi-Fi network name and password locally (hidden) when you left Set the Wi-Fi network on the Presto ticked, even if the Presto already has some, and tells you what will change. It only goes to the Presto's own /secrets.py, where an existing file keeps its other lines and only the two Wi-Fi lines change. The password is shown as * too. If you unticked the box, it keeps the Wi-Fi already on the Presto and asks nothing. It then has the Presto check that it can reach the daemon with those Wi-Fi settings, which can take up to a minute. This catches a wrong Wi-Fi password, a Presto that cannot look up the daemon's name, or a Presto on a network that cannot reach the daemon, before anything is replaced. Nothing is written, and an app that was running on the Presto is started again if this check fails;
5. shows a summary of exactly what will change, and asks one question, Continue? [Y/n]. Press Enter to go ahead, or n to stop with nothing written and AI Dash started again. (A Presto that is already running AI Dash goes dark just before this question, because setup has to stop the app to read it; answering n brings it back.) It then installs the app, verifies every file by SHA-256, and puts the previous app back if a write fails;
6. starts AI Dash and checks from the device that it can reach the daemon.

Both early checks ask only the daemon's /healthz answer, which needs no token, so the device token is not sent to an address that has not proved to be the daemon. If this computer is on a different network from the Presto and you are sure the address is right, run python presto_setup.py --skip-daemon-check to skip both checks. The admin page also looks for the daemon at the address you prepare and warns under the download if it cannot find it; that warning never blocks the download, because the daemon may be in a container or behind an address it cannot use itself.

On success it deletes presto_setup.enc and says so. On any failure it keeps the file, explains what to check, and lets you run the same command again.

4. What it keeps

• Firmware and Pimoroni's stock launcher are never touched.
• Existing device settings are kept. On a Presto that already has /ai_dash_files/config.py, the script changes only the daemon address and the device token in it. Every other setting, comment, the device name and the random device identifier stay, so there is nothing to ask. A new device gets a new file, with a new identifier. If the existing file is not in the usual shape (it does not parse, or sets the daemon twice), the summary says it will write a new one instead. The Wi-Fi is the exception, and follows the box you ticked or unticked on the admin page.
• Other files on the device are left alone. On a device that already runs AI Dash, app modules from an older build are retired.

If something goes wrong

What you see	What to do
unexpected error (RuntimeError in ..., line 123)	The script names the kind of error and where it happened, never its text, so nothing secret is printed. The setup file was kept: run the script again, and include that line if you report it.
needs two Python packages	You declined the private environment, or it could not be built (it needs the internet and Python's venv module). Run the pip install line the script prints, then run it again.
No USB serial device was found	Use a data cable, not a charge-only one. Press RESET on the Presto. List ports with python -m mpremote connect list.
not a Pimoroni Presto	The chosen port is another board. Run the script again and choose the Presto.
unlock code did not open	Copy the code again from the admin page (all 32 letters and digits), or prepare a new download.
different Presto app build	The daemon was upgraded between the two downloads. Prepare both files again.
could not join the Wi-Fi network	The settings are saved and the Presto keeps trying on its own. If you entered a new network, check its name and password (2.4 GHz only). A weak signal can also cause this: run the script again to retry.
has no Wi-Fi settings	You unticked Set the Wi-Fi network on the Presto, but this Presto has none. Nothing was written. Prepare the download again with the box ticked
did not come back after a restart	A Presto that updates over the air is restarted first. Unplug and replug it, then run the script again
KiB free and the app needs	The Presto's storage is nearly full. Remove files you do not need from it, then run the script again
app updates over the air stay off	The daemon could not make its update certificate. Check the daemon log for "update certificate", fix it, then run the script again
reached the daemon, but the daemon refused the device token	Set daemon.shared_token to a fixed value, restart the daemon, and prepare a new download.
could not reach the daemon	Check the address and port, and that the daemon is running and reachable from the Presto's network.

Deleting the encrypted file, losing the code or preparing another handoff does not revoke the shared device token. To revoke it, change daemon.shared_token, restart the daemon, and set the same value on every device that uses it.

A note on updates

A Presto set up this way updates its own app. When the daemon is upgraded to a release with a different app, the Presto is offered that app on its next poll, downloads it over TLS from the daemon, installs it into its spare app slot and switches to it. If the new app does not start properly, the Presto goes back to the app it had. The Status tab's Presto devices row shows each update and how it ended. Nothing is downloaded from the internet by the Presto: it only ever fetches the app of the daemon it was set up with.

Run Set up a Presto again over USB only to recover a Presto, to move it to another daemon, to change its Wi-Fi, or after flashing new Presto firmware: updates over the air are tied to the firmware the Presto had at setup, and switch themselves off until setup runs again. The admin page says so on the device's row.

Moving a Presto to a different daemon

A Presto learns where its daemon is from /ai_dash_files/config.py. When the daemon moves - a new server, a new address, or a copy on your laptop for testing - use the same two steps as a first setup, on the admin page of the daemon the Presto should use:

1. Open Set up a Presto, enter the address the Presto can reach and the daemon's device port, and leave Set the Wi-Fi network on the Presto unticked, because it already has its network. Prepare the download.
2. Run the script on the USB computer. It finds the Presto, changes only the daemon address and the device token in its settings, keeps every other setting including the name and the device identifier, checks that the Presto can reach the new daemon, and starts AI Dash. It also gives the Presto the new daemon's update certificate, so app updates then come from the new daemon.

The new token arrives inside the download, so you never copy it from the old daemon. The old daemon lists the Presto as not connected and forgets the row after a day; the new one lists it on its next poll. Moving back is the same two steps on the old daemon's page.

If the Presto cannot reach the new daemon, the script says why and keeps the download. Its settings are already written, so fix the cause (is the daemon running, is the address one the Presto can reach, is the device port open in the firewall?) and run the same script again. The table under If something goes wrong above lists what each message means.

Changing the Wi-Fi network

A Presto remembers one Wi-Fi network, in /secrets.py. If the router, the network name or the password changes, or you move the Presto to another building, it keeps trying the old one and shows Daemon offline; it cannot learn the new settings by itself. They have to go over USB, with the same two steps as before:

1. Open Set up a Presto on the admin page, enter the daemon's address as usual, and leave Set the Wi-Fi network on the Presto ticked. Prepare the download.
2. Run the script and type the new network name and password when it asks. The password is shown as *, one for each character, and it is written only to the Presto's own /secrets.py, replacing just the two Wi-Fi lines there. The script joins the new network, and tries several times with the radio switched off and on between tries, because a weak signal sometimes needs it.

A name of 1 to 32 printable ASCII characters and a password of 8 to 63 are what Wi-Fi allows. If the Presto cannot join, the script says so and keeps the download. The new settings are already saved and the Presto keeps trying on its own, so check the name and the password (and that the network has a 2.4 GHz band) and run the script again.

Firmware

If the Presto already shows its launcher carousel when you press RESET, the firmware is fine and setup needs nothing else.

Otherwise, download the latest with-filesystem .uf2 from the Presto releases page, hold BOOT while tapping RESET, and drag the .uf2 onto the RP2350 drive that appears. Then run Set up a Presto as above. After flashing new firmware on a Presto that is already set up, run setup once again: updates over the air switch themselves off when the firmware changes.

There is no manual install. Set up a Presto is the one way onto a Presto, because only the setup download carries the daemon's update certificate.

For developers: the repository sync tool

In a checkout, the sync tool installs the current presto/ sources into the spare app slot of a USB-connected Presto, verifies every file by its SHA-256 and switches to it. A Presto still on the single-folder layout is moved to the slots first. It never writes your settings, secrets, the update certificate or the firmware, so set a Presto up with Set up a Presto before using it.

.venv/Scripts/python tools/presto_device.py sync --port COM3
.venv/Scripts/python tools/presto_device.py check --port COM3

On macOS or Linux use .venv/bin/python. The tool refuses to pick a board automatically: you name the port. List the ports with python -m mpremote connect list.

In VS Code the same two actions are Terminal -> Run Task -> Sync Presto and Check Presto sync.

Start it

Press RESET on the Presto, find Presto AI Dash in the firmware carousel and tap it.

The entry uses the tagline Always in view. Never in your way. Older app installations may still be labelled AI Dash. The stock carousel supports only its built-in icons, so it retains the chart icon; the app's startup screen shows the Watchful Meter product icon. Routine app updates preserve the stock launcher and firmware.

The app joins the Wi-Fi network, then polls the daemon every POLL_INTERVAL seconds (15 by default). The first screen is Home, listing your accounts.

If the daemon is not reachable yet, the screen says Daemon offline and keeps trying. See Daemon offline and Wi-Fi drops.

The demo first

To see the screens without any account, turn on demo mode in the daemon's admin page (Settings, Demo mode), or start the daemon with DASH_DEMO=1. The Presto then shows a scripted set of sample accounts, each screen marked with a purple DEMO - SAMPLE DATA chip, and the daemon makes no provider request for it. That is also the quickest way to check the screen, the touch and the LEDs. Turn it off to see your real accounts.

You can also try the same screens in a browser, without a Presto: see it running.

If no service is set up and demo mode is off, the Presto shows No services set up / Open the admin page, with an amber bar and LED. That is the first screen on a new install: it means the Presto reached the daemon, which has nothing to show yet.

Polling and failure behaviour

Setting	Default	What it does
POLL_INTERVAL	15	Seconds between polls
RETRY_INTERVAL	12	Seconds between retries after a failure
WIFI_TIMEOUT	10	Seconds before a Wi-Fi attempt is given up
HTTP_TIMEOUT	8	Seconds before an HTTP request is given up
OFFLINE_AFTER_S	30	Seconds without a good poll before the offline screen

After an interruption the last good screens stay visible, marked STALE - retrying. Once OFFLINE_AFTER_S has passed and at least two polls in a row have failed, the app shows the error screen instead. A single failed poll that the next retry recovers never takes the screen away. A successful poll brings the selected card back on its own.

Next

• Add the first source
• Home display and the overflow strip