Problems with Samsung Series 5 Ultrabook and USBTinyISP

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Well, this is somewhat disappointing… I recently acquired a Samsung Series 5 530U3B Ultrabook which is really nice and was going to make my main laptop for on the work on the go. Unfortunately it supplies insufficient power to my USBTinyISP programmer. The effect is that when I try to program ATTiny45, I get this error:

Binary sketch size: 2,752 bytes (of a 4,096 byte maximum)
avrdude: verification error, first mismatch at byte 0x0040
 0x02 != 0x36
avrdude: verification error; content mismatch

The verification fails on random memory addresses. This means that I will need to add an external power supply to my custom programmer or find a USB hub with external power supply. I think that the latter will be the easiest.

Repairing Syma S031G helicopter

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A few weeks ago I found this boxed Syma S031G helicopter in a ModelZone store on a special shelf where they are selling broken or otherwise non working gadgets. There were more of those broken helicopters for sale, but they were in a range of £30 and were listed as having RC transmitter problems or other faulty parts. It wouldn’t have made sense buying one without investigating if repairs wouldn’t even cost more than a new heli retailing for £59.99 at the same store (or 30% cheaper on eBay). Mine only had a handwritten sticker “broken” stuck to it and a price of £9.99. A quick inspection through the box didn’t show any signs of significant damage and shop assistant was kind enough to let me open the box and check if it had all parts. Transmitter, charger, heli, instructions and even spare rear propeller was in the box so I decided to take the risk and bough it.

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A world of free IC samples

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The world is full of free integrated circuit samples, you just need to know where to look for them. Today I got a very nicely packaged batch of samples from Maxim Integrated. All I had to do was ask nicely :)

I filled all relevant information four days ago and today I have 2 x MAX7219CNG and 2 x MAX7221CNG LED display drivers. They retail at about £8 and £13 without shipping so it’s about £42 of free stuff! Will be using them to control 8×8 LED matrices I got a while back from Rapid Online.

Thanks Maxim Integrated!

Repairing Alba CR305IP FM clock radio alarm

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I bought this Alba FM clock radio a very long time ago at a car boot sale for £2. Seller was selling a bunch of them. It had everything in the box: power supply, cables, various iPod dock plastic bits and even AV cable. Took it home, plugged it in and… it was working, but no audio at all. I could control the iPod, set the clock and etc, but it just did not make any sound. Well, you know… it was just £2 :) So it was left in a cupboard for a very long time until today I decided to take it out and have a look at what’s inside.

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Using USBTinyISP to program ATTiny45 and ATTiny85

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There are a few different ways how to program ATTiny microcontrollers – lovely little chip with so much potential. I tried programming with Arduino Uno, but the solution was too clumsy with lots of wires connected to the breadboard from Arduino. Then I remembered that I have USBTinyISP and apparently it is one of the best ways to program these chips.

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Arduino touch sensor ky036

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I received a few Arduino touch sensors from DealExtreme just because they were dirty cheap and I have a few ideas where I could use them as device power switches. There is probably an easier way to build a touch sensor for Arduino without that many additional components, but let’s see what we can do with this cheap sensor for just $2.6 or less than £1.7.

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Forwarding Arduino serial port from Windows host to Linux guest using VirtualBox

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Forwarding Arduino from Windows host to Linux guest is straightforward, just select it from the list of available devices:

Once that’s done, the device will appear as /dev/ttyUSB0. The only problem is that file permissions for the device are 660 so you won’t be able to access the device unless you are root or set the permissions to 666 with

sudo chmod 666 /dev/usbTTY0

Note, that you would have to do this every time you forward the device or start the guest VM.

A more elegant solution exists (at least in Ubuntu). Just add yourself the the dialout group:

sudo adduser your-user-name dialout

Reboot your PC and you will be able to access the serial port without anything extra just by forwarding it to the guest Linux OS.

Mute/Unmute sound in Ubuntu 12.04 using command line

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Stumbled over this strange problem with Ubuntu and sound muting using command line interface (CLI). Everywhere on the internet I found that it can be done with amixer:

amixer sset Master mute

amixer sset Master unmute

amixer sset Master toggle

For some reason, muting works fine, but unumuting or toggle has no effect. Upon further investigation I noticed that by muting Master channel, “PCM” and “Master Mono” channels are muted too. Unmuting Master does not unmute those two channels. I could have solved this issue by running a bash script that mutes the sound with

amixer sset Master mute

… and unmutes all channels with 

amixer sset Master unmute
amixer sset PCM unmute
amixer sset "Master Mono" unmute

… but what fun is that? You can however mute and unmute with pactl. This requires just a single command line per action:

pactl set-sink-mute 0 1
pactl set-sink-mute 0 0