hardware on irq5 test

Custom Firmware for the Xiaomi AX3600 Wireless Router

Mon, 10 Aug 2020 23:53:00 +0000

As I have mentioned in the review, the stock firmware on the Xiaomi AX3600 wireless router is extremely limiting. On top of that, the firmware is also locked to install only authorized updates from the manufacturer. If you have been following the blog, you will know that I like the flexibility that ASUSWRT provides for customizing my router.

While there is currently an on-going effort to try and port vanilla OpenWRT for this router, I suspect that might take some time. In this post, I describe how to workaround the lousy firmware and configure the router with the advanced features I need.

Router Disassembly

It is recommended to have UART access handy, in case something bad happens and you need to recover your router, or if you want access to U-Boot, the bootloader. This would require you to crack open your router, so you might only want to do this if necessary. Feel free to skip this section if you are not interested in the hardware, or don’t need low-level access.

You need to unscrew 5 screws, 4 of which are hidden under the rubber feet, and one under the center sticker label. In the disassembled top view photo here, you can see the screw holes at the corners, as well as a missing chunk in the center of the heatsink for the mating screw post, directly aligned with the AIoT antenna and indicator LEDs.

Extending ASUSWRT Functionality, Part 2

Fri, 28 Dec 2018 00:11:00 +0000

Following up from my earlier post, Asus has released faster and beefier routers. But perhaps the more important change here is that they have moved from MIPS in the RT-N56U to ARM in newer routers. I have also upgraded to the RT-AC68U for better reception and hopefully to fix the poor battery life experienced by my Android tablet.

After upgrading, I noticed that the method I described back then no longer works. Someone also noticed this, as they translated key portions of my post into Chinese, while pointing out some of the steps that didn’t work.

In this post, I’ll summarize the key changes required to get it working again.

CXG 936d Temperature-Controlled Soldering Iron

Mon, 28 Dec 2015 00:09:00 +0000

A few weeks ago, I watched a Mike’s Electric Stuff video in which he was talking about options for portable soldering irons:

[youtube https://www.youtube.com/watch?v=sDMhh3p2nuM]

The first soldering iron he talked about seems to be interesting. It’s a soldering iron with temperature control, but everything is built into the form factor of a regular soldering iron. He also showed the insides of the iron, which uses a triac to control the supply, hence eliminating the need for the bulky 24V transformer found in most soldering stations.

Ever since my temperature-controlled soldering station died, I was left without one and fell back to using my cheap 20W iron. I was previously using the Duratool D00673 from element14, which is actually just a re-branded Zhongdi ZD-916. It was really expensive (S$120), so when it died after very infrequent use, I didn’t think it was worth it to get a replacement unit.

The 24V transformer is quite heavy and accounts for most of the weight of this unit, so trying to ship it from overseas was also not worth it. After it died, I tore it down and found that its construction was pretty crappy:

[tweet https://twitter.com/zxcvgm/status/468787841204375552]

If you want to see more teardown photos and a review of sorts, check out this EEVBlog forum thread. Of course I have verified that this crappy connector job wasn’t the cause of failure. My preliminary troubleshooting found that the power supply seemed to be working, but there was nothing on the LCD display nor was it responding (no beeps on keypresses).

Thanks to this video, I realized that there are alternative products that combine the best of both worlds.

Hacking Functionality into ASUSWRT Routers

Mon, 10 Dec 2012 00:10:00 +0000

This weekend, I spent some time to replace my aged Linksys WRT54G wireless router, which is running DD-WRT. The WRT54G is slow by today’s wireless standards and since I sync my iOS devices wirelessly, the speed was getting quite unbearable. When I bought my Macbook Pro in 2007, it already has draft 802.11n support and fast-forward to 2012, my iPad (1st generation) and iPhone 5 both support the 5GHz band.

The ASUS RT-N56U wireless router ranks up there on wireless performance, and the “feature” I was really after was a router that can run an alternative firmware such as Tomato or DD-WRT. The really good news is, I figured out how to get the functionality I wanted while still using the official ASUS firmware.

For proper reviews and better photos, you might want to check out these other reviews:

SmallNetBuilder: ASUS RT-N56U Black Diamond Dual-Band Gigabit Wireless-N Router Reviewed
FoxNetwork: ASUS RT-N56U or hardware NAT acceleration
(I quite like their professionally taken product photos and their reverse-engineering work)

Read on to find my short review, as well as how you can run your own programs on the router without using a third-party firmware.

SFF Server Build (Part 1): Short Cables

Mon, 01 Aug 2011 01:07:00 +0000

After 10 years, I decided to replace my 633MHz home server with something more modern. The fans on the system were making a lot of noise, especially the Slot-1 CPU cooler fan, which I don’t think I can find a replacement for. Also, the motherboard was very choosy about the power supply, meaning I could not use the newer, more energy efficient supplies; the voltage monitors claim the voltage is out of the acceptable range and refuses to continue beyond the POST screen.

I chose the MicroATX form factor, and the most compact case is the Silverstone SG02F because it places the power supply on top of the board. Most other cases I’ve seen have a similar layout to an ATX tower, but with a height reduction.

The wires are long and unwieldy because they assume you are using a normal ATX case, in which case you need relatively long cables depending on how the case is laid out. However when building a SFF machine like this, it gets really untidy. I decided to reduce the length of the cables.

Here’s the before photo of the wiring - the worst offenders are the SATA cables, the case front panel wires, and the SATA power connector.

Wiring (before)

Dissecting the SoundGraph iMON MM

Sat, 22 Jan 2011 17:01:00 +0000

Correction: The device is actually an iMON Multi-Median (MM), which includes an IR receiver and a remote control. My friend recently passed me a brand new unopened SoundGraph iMON IR receiver device. Here’s how it looks like: As you can see from the box, it supports up till Windows XP. If you’re thinking how the terms “Windows XP” and “brand new unopened” go together, it’s because he’s kept it for 4 years.

BenQ DW1640 drive tray (part 2)

Sun, 08 Aug 2010 21:05:00 +0000

Previously I wrote about trying to fix my BenQ DW1640 drive tray, but without replacing the belt. Of course it didn’t work. This time I went to Sim Lim Tower, where I know this particular shop called Space Electronics in the basement has a very wide selection of drive belts. Since I didn’t take the original belt out for comparison, I had to buy a few based on my memory. It turns out the smallest belt I bought worked very nicely as a replacement.

BenQ DW1640 drive tray

Sat, 05 Jun 2010 17:21:00 +0000

I own a BenQ DW1640 DVD drive and like many other people, the drive tray will no longer eject and retract properly. Following advice from a blog, I took apart my drive and indeed the tray mechanism is driven by a rubber belt. Although it seems to run properly by manually spinning it, it still doesn’t work after I’ve oiled some gears. I have no rubber band of such a small size lying around, so I either have to go out and buy another rubber belt to fix the drive for the next few months (maybe years), or I can go out to get a new drive that doesn’t use rubber belts.