Jul
09
2014
0

AVR – Detecting loss of power and writing to EEPROM

As part of a recent AVR project, I wanted a way to increment a counter and store it even if the power was lost. This could be done with an external flash memory device, but I wanted to use the internal EEPROM of the AVR.

The internal EEPROM is limited to around 100,000 writes. Independent tests have shown this can be doubled, but 100k writes is only about 27 hours if saved once every second, so not practical for a device I wanted to last at least five years.

It takes a maximum of 34ms (8448us per byte) to write a 32 bit (4 byte) integer to EEPROM. Due to the low power requirements of an AVR, I was confident that a decent sized (say 2200uF) capacitor would allow an AVR plenty of running time to complete EEPROM writes/saves before power is totally lost.
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Written by John in: AVR,Embedded Systems,Weather Station |
Jun
22
2014
0

Huawei HG630B. Inspecting the firmware

My previous posts on hacking the HG630B didn’t result in me getting root/console access to the router, so it’s time to look into the firmware.

I downloaded the latest version of the firmware. These are the details of the firmware I used:

Name: HG630bV100R001C55B017_upgrade_main.bin
Date: 25/06/2014
Size: 11 MB (12,322,608 bytes)
SHA-1: 375dbe5bc212840fbf7bf4216c76dc7dc08f571c
MD5: 62950060e08d4a357ea946f29dded3e5
CRC32: 5b4c5e27
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Written by John in: Embedded Systems,General Randomness | Tags:
Jun
11
2014
0

Huawei HG630B. Connecting to the UART

In my previous post I guessed that a five pad header on the rear of the PCB could be a UART of some type.

I quickly soldered a header to the pads, connected my Saleae logic analyzer up, switched on the router and started my snooping.

After a few attempts at finding a suitable ground pin, it wasn’t long before I had data that looked like this.

There's definitely some data there

There’s definitely some data there


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Written by John in: Embedded Systems,General Randomness | Tags:
Jun
09
2014
0

Huawei HG630B. Peeking inside

Let me be the first to say, it is really hard to open up the HG630B without breaking anything. You have to get the foot off first, this can be done with a small flathead screwdriver and a lot of patience.

Once this is done, there are four screws to undo and a myriad of plastic clips holding the front and back together.

You need to be careful of the antenna as it is partially attached to the case – It’s held in place by some slots inside the case.

Rear side of the HG630B board - Click to zoom

Rear side of the HG630B board – Click to zoom

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Written by John in: Embedded Systems,General Randomness | Tags:
Jun
08
2014
5

Huawei HG630B. Got Root?

Huawei HG630B. Got Root?

Telecom New Zealand are distributing the Huawei HG630B router as their ‘Home Gateway’ for residential customers. These routers are particularly interesting as they are Tri-Purpose. They have three WAN interfaces: an RJ11 socket for ADSL/VDSL, Ethernet for Fibre and USB for a USB cellular modem.
Telecom have been distributing these routers since at least the start of 2014, so a number of them are out in the wild.

The Telecom (Huawei) HG630B

The Telecom (Huawei) HG630B


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Written by John in: Embedded Systems,General Randomness | Tags:
Jun
01
2014
0

Yes, I’m still alive!

Wow, It’s June already!

Yes, I’m still alive, I’ve been busy, but I intend to start posting again soon.

Written by John in: General Randomness |
Feb
21
2014
0

Migrating to new server – again…

I’m in the middle of migrating to a new server.

If you have any problems on my site, please send an email to

Written by John in: Uncategorized |
Nov
01
2013
0

Now available in SSL

My website is now available over SSL by using the https:// prefix.

You will need to have the CAcert Root certificate installed – Follow the instructions here.

Once you’ve installed the CAcert Root certificate, click here to access the site securely.

Written by John in: General Randomness |
Jun
12
2013
0

Soldering ESCs

I’m using 30 Amp hobby King ESCs in my Quad Copter.

They each come with five bare ends which need connectors soldered to them.

Here’s a picture showing the result of about two hours of soldering and heat shrinking.

qc_escs

I’ve cut the DC power supply leads a little shorter so their length is perfect for my application.

Jun
10
2013
0

Fun with Loctite and Brushless Motors

It turns out four motors is four times the work of one… and four times the Loctite.

I’ve attached the spinners to the motors and the motors to the motor mounts using Loctite Threadlocker Red 271. This should stop any chance of the screws vibrating loose, but also has the downside of being very difficult to undo.

Overall, everything is starting to come together.

qc_motor

qc_arm