Used Laptops as a Computer Brain


Dear friends,

I’m an architect who think about my project called “Building as a Capsule - BaaC” which is a building that occupants produce most of their needs inside the building.
I think in the future we will work less than 4-5 hours a day inside our buildings.

So, is it possible we use old laptops (and/or mobile phones) as a computer brain and control sesors and everything with them?


Your question is very hypothetical and broad in scope. It would be difficult for someone to give you a meaningful answer.

It sounds like you want to learn how to automate a building. Perhaps you could try reading about building automation controls:

You might also want to try looking for a forum that is more about architecture and buildings. There may be some architects here, but mostly people use this forum to talk about hydroponics and aeroponics.


Thank you @wsnook, this is my mistake, didn’t clarify well.

I thought myself maybe it be possible we develop agricultural computer brains with used laptops/mobile phones.


Yes, it might be possible. But, that doesn’t mean it would be practical, reliable, or cost effective. It might. It might not. A lot would depend upon the skills of the people who built and maintained the control systems, what kind of access they had to tools and spare parts, and so on.


maybe also check out Angelo Vermeulen’s BIOMODD projects across the world.


Wow, thank you @thiemehennis


A used laptop could be used to run the logic, but you still have the need for GPIO pins. There are custom boards that break out this functionality, but when they cost more than a Raspberry, I am not sure what is gained.


Good point. I agree.

Old laptops with real RS232 serial ports and parallel printer ports can be interfaced to a variety of useful external hardware with cheap discrete components like resistors, diodes, transistors, and capacitors. But, if you have more modern laptop that relies on USB, the lack of GPIO pins is an obstacle.

Another problem is that old laptops often have the hard drives removed (destroyed for security purposes), and the batteries are too old to hold a proper charge. The battery problem is important because it can prevent the real time clock module from maintaining the correct time and date. Knowing the time and date is essential for controlling irrigation and lighting. Refurbishing old computers to the point of being useable is often not cost effective. I’ve spent a lot of time on eBay browsing for things I might buy as a starting point for projects of this nature. But, the math usually doesn’t work out. By the time I acquired all the parts I would need for a working system, I would be better off using new stuff with better specifications. If you had access to boatloads of free surplus equipment or e-waste, it might be a different story.

For phones, people have done interesting work to interface sensors using audio signals into the microphone jacks. But, bluetooth is much more common as a way of connecting phone peripherals. Building bluetooth peripherals to work with old phones would probably be a lot more hassle and expense compared to just building a device based on Arduino, Raspberry Pi, or whatever, that did the irrigation or light control tasks directly.

If I were to attempt a project like this, I would probably ignore the phones and look for old laptops or PCs that had the old style serial and parallel ports and a good reputation for being easy to service. I would plan on needing to replace the clock batteries and add new hard drives. For PCs, I would plan on needing to add battery backup power supplies (UPS), and for laptops I would plan on adding new power adapters and battery packs. That said, I would be a lot more inclined to just use a microcontroller with a real-time clock module because it would use a lot less power, be more reliable, and generally be less of a hassle. That’s basically why Arduino has become so incredibly popular.


Thank you @webbhm and @wsnook.
I just thought myself maybe we can use used laptopes, and mobile phones as brain computer and reduce waste, as part of Circular Economy - CE projects.

I think with collaboration with Arduino, Raspberry Pi, or whatever, hardware developers would be able use used devices for hardware development in the future.


Yeah, old laptops would probably work great for programming Arduinos or setting up Raspberry Pi.


All about this.

Random: old desktops are a great source of fans, heatsinks for LEDs, 12V power supplies.

I like the idea of using these devices as a gateway to access the device. This would eliminate the need for HDMI cord, HDMI Compatible screen, keyboard, mouse, etc.

People could just access the device locally (like when you set up an IoT device and you access it locally to connect it to home network) all the time and the MVP could allow for optional replication through that UI. That’s where companies could then plug in and provide hosted services and remote access to data.


What you’re describing sounds close to the model I used last year for my experiments with headless Raspberry Pi stuff that I controlled over SSH. I was very happy with that arrangement. NTP gave me a little trouble at first, but I got around that by wiring up an I2C RTC module to the GPIO pins, changing the kernel boot options to use the hardware clock, and then turning off NTP.


Awesome to hear this Peter, so hope for used new laptops and mobile phones even be a way to use them in computer brain projects and us their GPU and CPU power.