A survey of low-cost Linux boards for home automation, robotics, and DIY hardware — and why a ~$35 TP-Link MR3220 Wi-Fi router running OpenWrt turned out to be the sweet spot in 2011.
TP-Link MR3220 — a cheap Wi-Fi router capable of running OpenWrt Linux.
The hardware landscape
Over the past few years I studied several low-cost open-source hardware platforms for home automation:
| Board | Price |
| Beagleboard | $150 |
| Beagleboard xM | $150 |
| Beaglebone | $89 |
| Sheevaplug | $85 |
| Seagate Dockstar | $50 |
| Buffalo Linkstation Live | ~$150 |
| Linksys WRT-54GL | $50 |
| Asus RT-N16 | $90 |
| TP-Link MR3220 | $35 |
| Raspberry Pi | $35 |
Only a few of these are truly open in terms of hardware and software. The rest are commercial products with an option to run open-source Linux.
Requirements
- Decent processor, RAM, and flash — under $40 (2000 INR)
- Off-the-shelf product available locally (India)
- Open-source Linux support (OpenWrt / DD-WRT / Tomato)
- Lightweight with low power consumption
- Easy option to extend I/O peripheral access
Why a Wi-Fi router?
With these requirements, I narrowed down to the TP-Link MR3220. While the Raspberry Pi was the ideal solution on paper, it was extremely hard to get in 2011 due to heavy demand.
A Wi-Fi router makes practical sense: everyone already needs one for home connectivity. Adding basic home automation capabilities with little added cost — while saving you from running a 24/7 power-hungry desktop — is a good bargain at ~$35.
For enthusiasts, hobbyists, and students interested in embedded Linux, robotics, home automation, and DIY hardware, a router with USB + OpenWrt lets you skip hardware development and jump straight into firmware and software.
Demo: Android app controlling LEDs over Wi-Fi
No warranty void: You don't need to open your router. The openUI hardware is a USB add-on board that plugs into the router's USB port.
Hardware photos
My hardware collection — various Linux boards evaluated for home automation.
MR3220 router with the openUI USB add-on board connected.
Android app controlling LEDs via Wi-Fi through the MR3220 + openUI setup.
Close-up of the openUI USB board.
openUI hardware specs
openUI board featuring LCD, IR receiver, RTC, and I2C connector.
- AVR ATtiny2313 — acting as a USB HID device
- LCD display — for status output
- RC5 IR receiver — for remote control input
- PCF8563 RTC — I2C real-time clock with battery backup
- I2C connector — for extending with additional peripherals
- ISP header — in-circuit programming for ATtiny2313
Find the schematic, PCB layout, and source code for the openUI hardware and software in this follow-up post.
6 comments:
Nice solution...
Is it possible to put voice instructions in video presentation. This will help to understand it quickly.
Is kinda hard to understand with this kind of presentation. Better have a video tutorial.
Nice article, nice video, nice pictures, i liked everything about the article and really appreciate the way you have presented me the information it is really helpful for me..
If we should not hand a router with USB port .how can we use that for automation
If we should not hand a router with USB port .how can we use that for automation
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