Connecting a RAPT Pill

The RAPT Pill (KegLand) is a floating hydrometer that reports gravity and temperature over WiFi. RAPT Pill support in MakeWine is currently in beta — the Tilt is the fully supported device. It is a good sensor, and the setup is genuinely fiddly — several accounts, several screens, and two steps that will stop you dead if nobody warns you first. This is the whole thing in order, with what you should see at each step so you know it worked before moving on.

About 30 minutes the first time. You will need: the Pill, a charged battery, a 2.4 GHz WiFi network, a phone or laptop, and a hydrometer for the calibration at the end.

The single most useful fact up front: the RAPT setup hotspot password is kegland1. It is not obvious on the box. Write it down.

We set one up end to end before writing this, so every value below is what a real Pill sent, not what a datasheet says it sends.

Step 1 — Power the Pill

The Pill runs on a single 18650 battery inside the sealed housing, charged through a USB-C port on the circuit board. Two options:

• Just charge it. Sit it on its dock or plug in USB-C. KegLand recommends 24 hours before first use for a clean calibration. You should see a charge light.
• Swap in a charged 18650. Faster, but you have to open the housing.

⚠️ Opening the housing drifts the gravity calibration. That is recoverable — we re-calibrate at Step 9 — but it is why KegLand sells a wireless charger. If you do swap the battery, make sure the new cell seats fully and the housing closes without force. If it will not close, it is the wrong length or top.

You should see: the Pill wake. It wakes when taken off charge or inverted — check the sticker in the box.

Step 2 — Join the Pill's own WiFi hotspot

The Pill broadcasts a temporary network so you can configure it. On your phone's WiFi list, find the RAPT… network and join it.

• Password: kegland1

You should see: your phone connect, and a configuration page open. If it does not open by itself, browse to 192.168.4.1.

Step 3 — Give it your own WiFi

In that page, hand the Pill your home WiFi — this is where you enter your own password.

• It must be a 2.4 GHz network. The Pill does not do 5 GHz. If your router broadcasts one combined name for both, it usually still works; if pairing fails, that is the first thing to suspect.

You should see: the Pill reboot and join your network, and its setup hotspot disappear.

Step 4 — Let it update its firmware

On first connection the Pill will usually download and install a firmware update.

• Let it finish, and do not cut power mid-update. That is the one moment you can genuinely damage it.
• Newer firmware sometimes adds features, so it is worth doing before the next steps.

You should see: it report an update, then settle and come online.

Step 5 — Create a RAPT account and add the device

RAPT's own system lives in the cloud. Create an account at app.rapt.io (or in the RAPT mobile app), then add your Pill to it.

You should see: the Pill listed as online, with a live temperature and a recent "last seen".

Why WiFi and not Bluetooth? The Pill can run in Bluetooth mode for longer battery life, but Bluetooth only reaches a nearby phone — it never reaches RAPT's cloud, and MakeWine gets its data from RAPT's cloud. So the Pill has to be on WiFi for readings to reach us. (A Tilt has no WiFi at all, which is why a Tilt needs a phone or a Raspberry Pi nearby. The RAPT bridges itself — no extra hardware.)

Step 6 — Get the batch's token from MakeWine

Every fermentation batch in MakeWine has its own private ingest token. Open the batch → 📡 Hardware tab → the RAPT Pill card. Under Parameters you will find the token with a Copy button beside it.

Keep it private: anyone with it can post readings to this batch.

Step 7 — Create the webhook in the RAPT portal

This is the step that catches people out, and it is worth understanding why. A RAPT is not set up by pasting a URL. It is configured through a Custom Webhook form, and that form insists on a URL without a query string. If you paste a …?token=… URL into it, the token is quietly dropped and every reading comes back 401 while your setup looks perfectly correct.

So in the RAPT portal go to Webhooks → Create and fill it in exactly like this:

Payload:

{
    "temperature": "@temperature",
    "gravity": "@gravity",
    "battery": "@battery"
}

Those @ names are RAPT's own variables — it substitutes the real values when it sends. RAPT reports temperature in Celsius, gravity in SG and battery as a percentage, which is exactly what MakeWine stores, so nothing is converted anywhere in the chain. Keep @battery in: it is what makes the low-battery alert fire.

Parameters — where the token goes. Add a parameter:

• Type: Query String
• Key: token
• Value: the token you copied in Step 6

(A header called X-Ingest-Token with the same value works just as well, if you prefer.)

Devices tab: tick the Pill this webhook should use. Only the devices you tick will fire it.

Then Save.

Step 8 — Test it

Do not wait 15 minutes for the next scheduled send. Force one:

• In the RAPT portal, press Submit telemetry now. (Picking the Pill up and inverting it also triggers a send.)

Check two places:

• RAPT's Logs tab on the webhook shows every attempt. A 200 with the body {"status":"ok"} means RAPT sent it and MakeWine accepted it.
• Your batch in MakeWine — a new reading appears with temperature and gravity.

If it did not work, the Logs tab tells you where:

• 401 — the token is wrong or missing. Re-check the Query String parameter, and that you copied the token itself and not a whole URL.
• 410 Gone — recording is stopped on that batch. That is a deliberate "this batch is over" answer, not a setup error; press Start recording on the batch's card in the Hardware tab.
• No attempts listed at all — the Pill is not ticked in the webhook's Devices tab, the webhook was not saved, or the Pill has not sent yet.
• 5xx — a problem at our end. Rare, and worth telling us about.

Step 9 — Calibrate against your hydrometer

Straight out of setup, and especially if you opened the housing, the Pill's gravity needs calibrating. Temperature does not — it arrives correct.

1. Float the Pill in a tall container of plain water; a hydrometer test jar is ideal. It must float freely, not touching the sides or bottom. Tap it to knock off air bubbles.
2. Let it settle for a few minutes, until the reading stops moving.
3. Read your hydrometer in the same water and note the exact value. On a warm day it may read slightly under 1.000 — say 0.999. That is normal: hydrometers are calibrated to 20 °C and warm water is less dense.
4. Run the Pill's calibration in the RAPT portal and enter your hydrometer's actual reading as the known gravity — not a textbook 1.000.
5. You should see: the next reading match your hydrometer within a point or two.

Why match the hydrometer rather than aim for a perfect 1.000? Because what matters in fermentation is the trend — must at ~1.090 falling to ~0.995 — and you will be spot-checking with the hydrometer anyway. If the two instruments agree in the water, they agree in the wine. Ours went from reading 1.0134 in water the hydrometer called 0.999, to 0.9992 after calibration: a 15-point error down to a third of a point.

Step 10 — Set it up for real use

• Put the send interval back to something sensible. 15 minutes is the minimum and is plenty — a short interval is for testing and costs battery.
• Drop the Pill into your fermenter. Readings chart themselves in MakeWine from here.

Moving the Pill to a different batch

You do not rebuild the webhook. Change one thing:

1. In MakeWine, open the new batch → 📡 Hardware → copy its token.
2. In the RAPT webhook's Parameters, change the token value to the new one.
3. Leave the Url, Method and Payload exactly as they are. Save, then Submit telemetry now to confirm.

Quick reference

Related: Connecting fermentation sensors for the Tilt, and for what happens when a batch finishes.