BabyPod

This repository is for the hardware and initial setup. For the CircuitPython code that runs on the hardware, see the babypod-software repository. This documentation assumes you're using the latest commit of main from the software repository.

What is it?

BabyPod is a remote control for Baby Buddy. It's named that because it connects to Baby Buddy and has a click wheel like an old iPod.

Why use BabyPod instead of just your phone or something else, or even Baby Buddy in general?

• Simplicity: instead of finding your phone and keeping it charged, launching an app (and there's no iOS app), etc., just use a dedicated device that you can make whatever color you want to find easily and that stays charged a long time. It does one thing only. Deliberately, not all features of Baby Buddy exist in BabyPod, just the most commonly used ones.
• Full control of your data: you have total privacy over your data because BabyPod talks directly to your Baby Buddy instance's API.
• Quick access: the most commonly used things are shown first, and extra data can be added later. For example, if you record a diaper change, you can log if it was wet and/or dry, but it doesn't ask for color because usually it'll be the same and you can just add it later directly in Baby Buddy if not. Print and build multiple BabyPods if you want and leave them in places you frequent, like your baby's nursery, a place where you feed, etc. For multiple children, you can print and build multiple BabyPods and assign each one to a specific child.
• Open source: change it to do what you want. As long as you don't sell it, I don't care what you do with it. Contributing back would be nice!

Because this is just a remote control, you need to install Baby Buddy somewhere beforehand, like to your computer if it's on 24/7, a home server, a Raspberry Pi, AWS/GCP/Digital Ocean/Clever Cloud, or something else. This guide assumes you've already got Baby Buddy running and now you want a remote control for it.

Hardware

To build a BabyPod, you 3D print some parts, stuff it with some electronics with easy soldering, and load the software.

Parts, tools, and supplies needed

Here's what you need to build a BabyPod. Prices are USD at the time of authoring and you can possibly find parts cheaper elsewhere, but this is to give you a nominal idea of how much the project costs.

Note that you can get most of these parts from the manufacturer directly like Adafruit and Sparkfun, and also resellers like Digikey, Mouser, and if you're lucky, Micro Center locally. The prices on Amazon are usually inflated.

Deviate from the parts list at your own risk, but do not get a different battery! Adafruit batteries have polarities that match their own boards, and using a battery off Amazon or elsewhere may not match and destroy your board or even start a fire!

Part	Quantity	Price
Adafruit ESP32-S3 Feather with 4MB Flash 2MB PSRAM	1	$17.50
Sparkfun 20x4 SerLCD	1	$26.95
Adafruit ANO Rotary Navigation Encoder to I2C Stemma QT Adapter	1	$4.95
ANO Directional Navigation and Scroll Wheel Rotary Encoder	1	$8.95
Lithium Ion Polymer Battery - 3.7v 2500mAh	1	$14.95
STEMMA QT / Qwiic JST SH 4-pin Cable - 100mm Long	2	$0.95
STEMMA QT / Qwiic JST SH 4-pin Cable - 50mm Long	1	$0.95
Small Enclosed Piezo w/Wires	1	$0.95
Adafruit SPI Flash SD Card - XTSD 512 MB	1	$9.50
Adafruit PCF8523 Real Time Clock Breakout Board - STEMMA QT / Qwiic	1	$4.95
Total		$91.55

You will also need the following supplies. The manufacturer doesn't matter but some examples are linked below:

• A CR1220 button cell battery
• Screws:
  • M2x4, quantity 2
  • M2.5x6, quantity 4
  • M2.5x4, quantity 8
  • M3x4, quantity 4
  • Self-tapping countersunk M2x4, quantity 6
• 22AWG solid core hookup wire
• 3D printing filament of your choice; PETG works nicely
• A USB C cable capable of both data and charging
• Solder
• 1.75mm transparent 3D printing filament, ~6mm worth; this acts as a light pipe and you won't actually print using it

And lastly, tools:

• Small screwdriver
• Wire cutters/strippers
• Soldering iron
• A 3D printer
• A computer with a USB C port

Printing the enclosure

You can print the enclosure in either one or two colors. Whichever you choose:

• Infill amount and style doesn't matter much because there isn't much to infill.
• Don't use supports.
• 0.2mm layer height is best. Avoid variable height layers because it'll make the LCD and rotary encoder insets look weird.
• If you set the bottom infill pattern to "Archimedian Chords" on both parts, it'll look prettier. Same if you use PETG and print on a textured plate.

If you're editing BabyPod.scad, your system needs the font "SignPainter" installed.

One color

Print Case.stl upside-down and Baseplate.stl as-is.

Two colors

Printing in two colors requires a printer that supports multiple filaments or clever use of GCODE.

Print Case.stl and Faceplate inlays.stl as a multipart object upside-down (top of the faceplate and inlays facing the bed) and Bottom case.stl as-is.

Layout

Here is where everything fits in the enclosure. The perimeter of each part has holes for self-tapping countersunk M2x4 screws and line up once you press the two parts together. If they don't line up, something between the two parts is in the way, like a wire.

Case.stl

• The red board is the LCD module. It is held in place to its standoffs with four M2.5x6 screws.
• The rotary encoder is obvious. It uses four M2.5x4 screws. Note the position of the pins on the left side.
• The hole for the USB C port on the Feather is visible. Next to it is a hole for the 1.75mm transparent filament to act as a light pipe to the charge LED on the Feather.

Baseplate.stl

• The blue rectangle is the battery. The cable will exit by the bottom-left. It is press fit.
• The green board is the RTC. The vertical orientation doesn't matter. It uses four M3x4 screws. The battery faces up and the STEMMA QT ports face down.
• The yellow board is the Flash SD board. The components face up and the flat surface faces down. It uses two M2.5x4 screws.
• The white board is the Feather. It is screwed in using two M2.5x4 screws in the front near the USB C port, and in the back the smaller holes of the Feather use two M2x4 screws.
• The piezo isn't visible. It is under the yellow Flash SD board. It is press fit like the battery. The hole in the piezo faces down and the wires exit through the hole in the circle.

Assembly

You want to install CircuitPython and set up the software before assembling the hardware. Remember you also already need a running instance of Baby Buddy!

CircuitPython setup

Install the latest stable release of CircuitPython 9 onto the Feather, even though it was probably preinstalled. You want to get the right version and erase any unnecessary files.

1. Download CircuitPython 9 for your specific board. Get the .bin version, not .uf2.
2. Connect the Feather to your computer via USB C.
3. Press and hold the Boot button, briefly press Reset, and then release the Boot button. This puts the board in a bootloader mode.
4. In Google Chrome, go to Adafruit's ESPTool. Firefox and some other browsers don't work because the tool needs WebSerial support.
5. Click "Connect" and select the Feather. The device's name will vary, but ultimately you should see a successful connection message.
6. Click Erase and wait about 15 seconds until you get a success message.
7. Click the first "Choose a file..." button and select the .bin CircuitPython image you downloaded, then click "Program."
8. When prompted to do so, press the Reset button on the Feather. A few moments later, a drive named CIRCUITPY should show up on your computer.

Keep the Feather plugged in for the next steps.

Load the BabyPod software

1. Download the latest release of the BabyPod software and extract the zip file to a new folder somewhere.
2. In the extracted files, rename settings.toml.example to settings.toml. Make sure your OS doesn't sneak a .txt extension onto it.
3. Create a free account on adafruit.io. You'll need your username and API key in the next step. You can get those when you're logged in by clicking the yellow key icon at the top-right of the page.
4. Open settings.toml in a text editor and modify it as comments in the file show, then save it.
5. Copy everything inside the new folder (not the folder itself) including your renamed settings.toml file to the CIRCUITPY drive. Overwrite anything already on the drive.

Even though there isn't much to copy, it might take a few minutes. At this point, all the software is ready to go, and once you've assembled the hardware, it should connect to your Wi-Fi, log into Baby Buddy, and run normally.

Soldering

Overview

Here is a logical diagram of how everything connects. This isn't physically how everything is laid out in the enclosure but just shows what pins go where. Don't start soldering yet!

• Blue wires are STEMMA QT cables (I2C). These don't get soldered. On boards with two STEMMA QT connectors, the connections are interchangeable. The LCD's connector is labeled "QWIIC" which is just Sparkfun's name for the same connector.
• The yellow wire is the only soldered wire on the rotary encoder and connects its INT pin to the Feather's 11.
• Black wires are all GND and red wires are all +3.3V. The black wire is the only soldered wire on the RTC.
• The orange wire on the piezo goes to A3.
• The green wires are all used for SPI communication for the Flash SD card.
• The battery plugs directly into the Feather's battery terminal.
• The rotary encoder dial itself isn't shown, but it gets soldered to its respective board directly.

Before soldering, orient yourself to where everything mounts to the 3D printed parts. You want to use just enough wire to reach each connection point, but not too much excess or you won't be able to fit everything inside the enclosure. It may help to keep Adafruit's pinout documentation of the Feather open while you're soldering. Triple check which pin you're soldering to before you actually do it!

Many of the boards ship with a strip of headers included. You won't use them.

Soldering

Solder the rotary encoder dial to its breakout board. It only fits one way. Be careful not to skip any connections.

Then solder the following connections from the respective devices to their targets:

Device	Pin/Wire	To
Piezo	Black wire	GND on the RTC
Piezo	Red wire	A3 on the Feather
Flash SD card	VIN	3V on the Feather
Flash SD card	GND	GND on the Feather
Flash SD card	SCK	SCK on the Feather
Flash SD card	MISO	MI on the Feather
Flash SD card	MOSI	MO on the Feather
Flash SD card	CS	10 on the Feather
Rotary encoder board	INT	11 on the Feather

The piezo wires are very thin, so be careful. Less solder is best.

Note that all the soldered wires are between the Feather and the Flash SD card with two exceptions:

• The rotary encoder's INT pin goes to the Feather.
• The piezo's black ground wire goes to the RTC.

Mount components

When screwing in components, use just enough force to keep things in place. Don't over-tighten the screws or you'll strip the non-existent threads in the 3D printed parts and need to print them again. Repeatedly screwing into the same standoff may also strip it, even if it's not over-tightened, and you'll need to reprint.

The plugs on STEMMA QT cables only fit one way. Don't use a lot of force or you can easily bend one of the thin pins in their ports.

If you need to, you can change the order of the steps below if shoving everything into the enclosure is finicky.

1. Connect the LCD to the rotary encoder using one of the 100mm STEMMA QT cables. It doesn't matter which port on the rotary encoder you use. On the other STEMMA QT port on the rotary encoder, plug in another 100mm STEMMA QT cable. It'll later connect to other components, but not yet.
2. Screw the rotary encoder into place with four M2.5x4 screws. The set of pins on it, including where you soldered the INT wire, should face towards the cutout for the LCD and the star with the Adafruit logo by the outer edge of the case with the STEMMA QT connectors pointing to the top and bottom of the case.
3. Use four M2.5x6 screws to screw the LCD into place into the case. The "QWIIC" connector (what Adafruit calls "STEMMA QT") should point towards the rotary encoder and the LCD screen faces out towards the cutout for it.
4. Set aside the case for now.
5. Press the piezo into place in its circle on the baseplate with the hole facing down and the wire protruding through the cutout in the circle. You can keep the white bit of tape on.
6. Screw the Flash SD board into place above the piezo with two M2.5x4 screws with the components facing up.
7. Put the CR1220 battery into the RTC; note the polarity. Screw the RTC into place with four M3x4 screws with the battery facing up. The direction doesn't matter.
8. Screw the Feather into place with the USB C port facing towards the cutout in the case and the board's components facing up. Use two M2.5x4 screws for the larger holes and two M2x4 screws for the smaller ones.
9. Plug the 50mm STEMMA QT cable into the Feather's port and into the nearest port on the RTC, then connect the STEMMA QT cable from the assembled case with the rotary encoder into the other port on the RTC.
10. Press the battery into its retainer with the cable by the bottom-left, assuming the Feather's USB C port is facing you. Don't plug in the battery's cable into the Feather yet.

Testing before final assembly

At this point, you should have all the connections made except the battery. You can test the BabyPod by plugging in the USB C cable and seeing if it starts up. If you hear a beep and the main menu shows up then your connections are likely good.

If you don't hear a beep but everything else seems to work, make sure the piezo is soldered properly per the connections above and that the RTC's STEMMA QT connections are solid.

Final assembly

If the test passed, continue on:

1. Unplug the USB C cable from the Feather.
2. Plug the battery into the Feather. The BabyPod will boot up.
3. Carefully press together the two 3D printed parts, being sure to align the USB C hole to the Feather. Make sure the reset hole guide is unobstructed and there are no wires stuck underneath it.
4. Screw the backplate and the enclosure together with the countersunk self-tapping M2 screws. Be especially careful not to over-tighten!
5. Shove the little bit of transparent 1.75mm filament into the hole next to the USB C connector until it is flush with the outside of the case. It acts as a light pipe for the Feather's charge LED. You might want to use pliers. If you want, carefully apply a tiny drop of superglue to hold it in place, but friction alone is probably sufficient.

Basic usage

Head over to the babypod-software repository for how to use the BabyPod.

Troubleshooting

Shove a paperclip in the hole under the rotary encoder to press the Feather's reset button. This is a hardware reset that will always work as long as the Feather has power. Additionally you can reset the BabyPod by pressing and holding the Down button, but this only works if the BabyPod is ready and waiting for user input.

Hint: to take apart the BabyPod, there are tiny divots on the left and right of the enclosure. You can hook your fingernails in there for leverage.

Power and wiring-related

• Most obviously, check all your solder connections. It's easy to accidentally solder the wrong pin, or common mistakes like too little or too much solder.
• Is the battery charged? The battery is 2500mAh and the Feather's slow charging speed means it can take a long time to fully charge from 0%. Even with a dead or even disconnected battery, the BabyPod should still function when powered by USB. If you don't see the orange charge LED illuminated by the USB C port then the board isn't getting power.
• Is the battery plugged into the Feather completely? Be careful removing the battery connector; it's an extremely tight fit, so gently work it out with pliers or a screwdriver and never pull on the battery wires! The battery percentage on the screen is nonsensical without a battery plugged in: it often shows 100% despite no battery being present.
• Did you use an Adafruit-brand battery and did you buy it from Adafruit, Digikey, or Mouser directly? If you didn't, then your battery probably has the wrong polarity and would have destroyed the Feather and possibly other components the moment it got plugged in.
• Are all the relevant STEMMA QT connections in use? Every available STEMMA QT port (or QWIIC in the case of the LCD) should be in use. Technically speaking the order of the connections doesn't matter, but do be sure everything is connected in a chain and there are no empty STEMMA QT ports.
• Is the screen completely blank? Assuming of course everything else is wired correctly, the battery might be fully discharged. During soft shutdown, the screen should still show the charge percent and "⊙ Power". If the LCD fails to initialize in software, it may appear blank too even if the backlight is on; see below for troubleshooting that.
• Is the charge LED flickering? The battery is probably not connected properly or needs replacing. The charge LED flickers when the Feather believes no battery is connected.
• Is pressing and holding the Center button not turning off the BabyPod, or does pressing it when the BabyPod is off not wake it back up? Make sure USE_SOFT_POWER_CONTROL is set to 1 in settings.toml.
• Similarly, is the BabyPod shutting off automatically after a few minutes, but you have a physical power switch so it won't wake back up? Set USE_SOFT_POWER_CONTROL to 0 in settings.toml.
• Is the BabyPod waking up spontaneously without you touching it? Make sure the INT pin is wired properly to the Feather's 11 pin. A loose connection could trigger false interrupts. Also make sure there's no moisture in the rotary encoder that could be causing a short and that the center button isn't stuck down. Additionally, pressing and holding the center button turns off the BabyPod but continuing to hold it can cause it to wake back up immediately.

Software-related

• Do you have at least one child in Baby Buddy? The BabyPod auto-selects the first child it sees, and if you have none, will crash.
• Does your API user have enough access in Baby Buddy?
• Did you install CircuitPython 9 and load all the code, including the relevant libraries? Have you tried an older version of CircuitPython (still 9.x.x) in case there was a breaking change?
• Is the code crashing? Connect to a serial console and watch the output. Note the code disables the auto-reload when you write a file which is different from CircuitPython's default operation. In a serial console, you can press Ctrl-C to stop the code and then Ctrl-D to reboot which will capture all the output from the moment it boots up. If you're using macOS, then tio makes it easy to use serial consoles in the terminal; the device is /dev/tty.usbmodem*. In the console do you get errors about I2C problems or missing pullup resistors? Make sure all the STEMMA QT connections are good. Swap the cables with new ones if need be.
• Does random crap like corrupted characters show up on the screen? Check that all the STEMMA QT connections are secure, not just to the LCD but to the Feather, RTC, and rotary encoder too.
• Does the menu show up but you get various errors when you actually try to do something, like recording a feeding or changing? Your settings.toml is probably wrong, either for the Wi-Fi credentials, Wi-Fi channel if you specified one, or Baby Buddy's URL or authorization token. The serial console should help you here.
• Are you using a recent version of Baby Buddy for your server? Or perhaps your version is too new and there's an API-breaking change?
• Are you getting errors about incompatible .mpy files? You need to install the right version of CircuitPython (9.x.x).
• Does setting the clock fail? You omitted the adafruit.io credentials or got them wrong in settings.toml. If you rotated your key on adafruit.io, you need to update it in settings.toml too.
• Maybe there's a bug. Let me rephrase that: there are most definitely bugs and maybe you ran into one. Check the GitHub issues for the software and submit a new issue if you don't see yours covered. Pull requests are greatly welcomed if you see a problem and have a fix!

Other things to check

• Is the BabyPod booting up normally, getting to the main menu, but then after a few seconds says "Rebooting" and does so? The Down button is being held. Assuming you aren't touching it, the tolerance between the rotary encoder and the enclosure might be too tight. Try to adjust it by putting thin washers on the standoffs that hold the rotary encoder.
• Is the LCD contrast adjusted? The Sparkfun LCD contrast, used in current BabyPod builds, is adjusted through code so you'll need to poke around in the CircuitPython REPL to adjust it. The code supports an Adafruit LCD backpack too, and that uses a potentiometer to adjust the contrast.
• When plugging in a USB C cable, is it snapping fully into the port on the Feather, or is the enclosure preventing it from going all the way in?
• Does your USB C cable support both data and power? Test it with another device to be sure. Avoid USB A to USB cables and try to use USB C-to-C, assuming your computer has a USB C port too.
• Is the rotary encoder acting erratically, like "up" is acting like "down"? Make sure it's oriented properly: the row of pins is towards the center of the case, not the outside edge, as pictured above.
• Is the RTC failing to initialize or acting weird? Make sure the CR1220 button cell battery is installed and that the polarity is correct.
• If the clock keeps drifting or getting set every time you start up, the battery in the RTC is probably dead.
• If the RTC's timezone is consistently off by an hour or a multiple of 60 minutes precisely, then adafruit.io might be getting your timezone wrong.