Tuesday, 27 October 2015

HDMI Converter Upgrade

One minor problem with working with the Raspeberry Pi is the lack of a VGA display output. I say minor because most of the time the Pi is being used with a TV with an HDMI input or in 'headless' mode where I am logging in from elsewhere on the network.

Over the years I have acquired a small number of LCD VGA displays and I have a couple of these in the workshop along with a 32-inch LCD TV I picked up. Being able to use one of these displays with the Raspberry Pi was always going to be handy so I needed an HDMI-to-VGA adapter. These aren't overly expensive (£15 will buy a good one from CPC), but always on the lookout for a bargain I purchased the one below on eBay for £2.50 (direct from China).

The problem is that the Raspberry Pi HDMI output has very limited current on the 5-volt line, not enough to successfully run the adapter. Also, the Pi checks the HDMI output very quickly for a display and the adapter needs time to boot up so being able to run it from a separate supply would be an advantage. The Pi can be programmed to lock to HDMI and also to delay in checking for a display, but I wanted to avoid that for the time being.

Cheap HDMI to VGA adapterThe adapter came apart very easily by simply prising the bezel out from around the VGA socket. The HDMI specification gave me pin 18 as the 5-volt line so I was able to identify that on my adapter this was a purple wire which went to a pad on the PCB marked '18' (Doh, but it is always a good idea to check!). An old lightweight USB cable did the job for power and after cutting the purple HDMI wire, I soldered the red USB wire in its place on the PCB and the black USB wire to a spare ground point. Interestingly this PCB had pads for both a micro-USB socket and a small DC power socket (maybe 1.7mm or so) so a more sophisticated upgrade would be possible.

I tested the set-up to check it was working and have now bored a hole and re-soldered the power cable to neaten the whole thing up. It looks pretty professional now and the picture quality on a Panasonic VGA monitor is excellent.

I'm thinking of buying another of these and hard-wiring it into another VGA monitor I have to give the monitor an HDMI input.

Tuesday, 7 July 2015

Netbook TV on Linux Mint 17

Got around to testing this little Pinnacle Nano Stick TV dongle which came with a Freegle box of obsolete electronic items. I wasn't sure if it would work easily on Linux, but as usual, just plug and play. I downloaded the Me-TV package and off it went. The software can record to the netbook's hard drive, DVD copies can be made and interestingly the video codec can be selected so the RTE stations in MPEG-4 HD can be viewed. Not bad for, well nothing really.

Sunday, 22 March 2015

Strike a Light!

I bought a couple of these Light Strike rifles for my son for Christmas 2013 when they were being sold in Home Bargains, but it turned out that they were an end of line item which amazed me because they are one of the best toys we've ever come across.  So good that I've bought up any final stock that's appeared reasonably priced on eBay.  There are some cool attachments for the rifles, my favourite being an underslung grenade launcher.  We had one of these with the first rifle, but I got another for £4 on eBay last week.  Only difference was that this new one vibrated and the old one didn't.  Mysterious, so I opened the older one up and discovered it indeed had a motor with a small eccentric weight attached.  This worked with 5 volts applied so I carefully re-soldered the connections and the tiny surface-mount transistor which drives the motor.  Reassembled and connected to the rifle it now vibrates. Result and an easy repair.

Thursday, 1 January 2015

Linux just... works

I love Linux. I mean take this example of an old netbook I got on Freegle. The hard drive was toast so I swapped in one from another netbook with a smaller screen. This already had Ubuntu on it, but everything just worked first time, nothing more to do. I connected it to the network and it asked if I wanted to upgrade to Ubuntu 14.10 and update software. Sure, go ahead. So it did. No worries.