I turned an old Android phone into a DIY smart home hub — here's how it works

Building a cost-effective, entry-level smart home is an experiment that should come with careful planning and an emphasis on simplicity. Overengineering can cause frustration, particularly when your devices suddenly turn on or off out of nowhere, leaving you confused with a screen full of buttons and no idea where to tap.

I only put my setup together with an IR blaster, two Android phones (you only need one if you don’t want a DIY home hub), a smart plug, and a couple of apps. Before configuring anything, I anticipated the project might become convoluted rather than convenient, so optimizing the control interface and day-to-day interactions was my priority throughout.

After all, this project turned out to be a huge success: I now have a budget-friendly, self-built smart home that is well-suited to my needs and lets me retain a certain level of control over the system.

Can’t find your TV remote? Use your phone instead

My first step was setting up an IR blaster to control my home appliances, and Tuya offered me one of the cheapest hardware options in my area. While I expected to use MacroDroid for automation right away, Tuya’s built-in Geofence Entry and Exit routines could effectively handle my home arrival and departure triggers.

To add a device for phone control via IR, connect the blaster to a 5V-1A power supply, open the app, select “Add device” from the top-right menu, and pair the remote with your phone. In the Smart IR interface, most basic household appliances can be configured using Quick Match, and teaching them to learn the commands from original remotes is simple with on-screen instructions. Your phone is now a multifunctional controller in your pocket, replacing all the physical remotes scattered across your home for ACs, fans, and TVs, with an interface that seamlessly simulates their functionality.

As long as my IR blaster stays plugged in, it runs buttery-smooth and works exactly as intended. To take convenience further, I linked Tuya to Google Home and created a Google Home Favorites widget on my home screen for quick access (note that you can only pin a device to your Google Home favorites after assigning it to a specific room). I know laziness is a sin, but I don’t want to keep getting up while focused on work. After all, isn’t that the whole point of a smart home?

That said, after testing various automation routines, I kept only one location-based trigger that turns on the AC right before I arrive home from work. Once inside, I adjust the AC temperature or toggle the TV on my phone based on real-time weather and personal comfort. This way, I seize manual control over my system rather than having it act on predetermined patterns or consistently predict my next move, which I don’t even know myself most of the time. A rigid schedule often fails to accommodate real-world variables and our ever-changing needs. If you want to automate more aggressively, you can experiment with the Automation and Tap-to-Run sections, or try Tasker or MacroDroid (I’ll get back to it shortly).

As for the downsides, I sometimes need to be in the same room with the target device since IR signals don’t penetrate walls. Other glitches occasionally occur, especially when I use my physical remote to toggle a device on or off, yet resyncing it is pretty straightforward.

I think advanced devices like presence sensors, smart door locks, smart thermostats, or motorized curtains aren’t necessary for an entry-level setup, as basic solutions can address most of my everyday hassles. Building a smart home is a gradual upgrade journey rather than throwing money at a bunch of smart devices and overautomating them, only to forget what does what.

Can a DIY smart hub help you go totally hands-free?

This is the most optional yet rewarding part of the project: converting my old Pixel into a hands-free, voice-controlled home hub. I started by navigating to Settings → Google → Settings for Google apps → Search, Assistant and Voice → Gemini → Talk to Gemini hands-free, then toggling on ‘Hey Google’.

I quickly encountered Gemini‘s biggest UX friction point in home automation compared with Google Assistant: Gemini Live requires a manual trigger to initiate a new session. The ‘Hey Google‘ prompt worked for individual queries, but it couldn’t sustain an ongoing conversation. I love Gemini’s conversational versatility, so I needed a way to activate Gemini Live remotely using my Galaxy phone — without having to reach over or get up to hit a tiny icon on my plugged-in Pixel.

I solved this friction point using a MacroDroid trigger. Before anything else, a quick word on why I chose MacroDroid over Tasker: it offers a 7-day free trial, so you can ditch it if it’s not for you, and its price remains reasonable after the trial ends. It doesn’t mean that Tasker is inferior in any way.

Back to the project, here’s how I configured distant Gemini Live activation on my Pixel 3 XL (the receiver unit):

1. Set up a new macro: In MacroDroid, add a new macro and select Webhook Trigger under Connectivity. This generates a URL that acts as a remote switch.
2. Wake the screen: Add Screen On to wake the Pixel when it’s activated.
3. Launch Gemini: Add Launch Application → Gemini, then select Force new to initiate a fresh session each time.
4. Add a brief pause: Add a two-second Wait Before Next Action to give the receiver enough time to render the UI.
5. Simulate the tap: Add UI Interaction → Click → X, Y Location. (Tip: enable Pointer Location in Developer Options to identify the exact coordinates of the Gemini Live icon).
6. Save and export: Save the macro and send the generated Webhook URL to the sender unit (a Galaxy Phone in my case).

And the corresponding steps on the sender unit (my Galaxy phone):

1. Create a trigger button: In MacroDroid, create a new Widget Button macro and give it a distinct color.
2. Send the signal: Add an HTTP Request action, set the method to GET, and paste the Webhook URL from the receiver.
3. Bring it to the home screen: Place a MacroDroid Custom Widget on the sender’s home screen, matching the color you set. 

The ‘Hey Google’ hotword frequently failed during my time using it as the primary activation method, because loud music or ambient noise often overpowered my voice. Meanwhile, the MacroDroid trigger instantly paused Spotify, activated Gemini Live, let me handle my request through a full conversation, and seamlessly resumed the music playback after I finished.

I also tried some third-party kiosk launchers to replicate a Nest Hub UI. Yet later, I realized that the Pixel launcher with native widget support could be a real, practical option for its responsiveness and resource efficiency. My Pixel hub isn’t locked to kiosk mode, offers quick app shortcuts, and still receives notifications. Plugging it into my laptop also enables constant charging and screen mirroring, a nice add-on in many situations, and I can use this hub in both portrait and landscape modes. To avoid battery degradation, I paired it with a smart plug programmed for a two-hour charge/four-hour break cycle.

Ultimately, it doesn’t look much like a retail Nest Hub display, but it’s always within reach by both voice and touch.

Is a ‘set and forget’ setup even realistic?

Simply put, no. If you’ve gone that far to set up various devices, chances are you won’t forget what you’ve built. Instead, you know exactly what happens, and when — you might even find yourself anticipating those automated routines. 

And that’s a good thing. Venturing into smart home building at any level would make tweaking and system fine-tuning second nature. A true “Set and Forget” setup is a far more expensive, complicated game to play — and I honestly think most casual users don’t even need it.

Overall, my setup is cost-effective, simple, and well worth the effort (at least for my needs). The lack of dedicated sensors hasn’t undermined the experience in the slightest. I rarely give out advice, but if you don’t have a basic smart home setup yet, giving it a try certainly won’t hurt.