Bloody Crappy Old Electronics!!! Part 2 – Bloody Crappy Old Mechanics!!

It would seem that Omnibot 2000’s mechanised tray is making a nasty terminal sounding grind whilst operating…. 

This Nerdyness is not going smoothly!

After a strip down (Complete tray strip down….Goddam how many parts does a mechanised tray need???) it appears that the DC motor itself is the cause of the sound… 30 odd year old bearings are probably the cause.

Have also found one of the main drive gears cracked and slipping round its shaft.

1) DC motor soaked in WD40. Leave it to soak in over night.

2) Gear fixed with superglue and then glued onto shaft and drying over night.

Lets see if we can get something operational tomorrow??

So far:

The tray not working correctly. Stripped down in pieces at present.

The remote, I think, is working correctly, although its almost impossible to tell without a working one to compare. Currently stripped down in pieces.

Omnibot 2000 doesn’t do much apart from erratic moves when his battery gets low… Tapedeck works, speech from remote to speaker works…. no remote functions. He’s currently in one piece but I think he’s gonna be stripped down before long….

Bloody Crappy Old Electronics!!!!!!!

So after stripping Omnibot 2000 down completely, scrubbing, repairing, replacing and reassembling… and then spending a very hot sweaty hour and a half finding the remote control…. The bloody thing doesn’t work!!!!

All the light come on on Omnibot. Light comes on on remote. But one just ain’t controlling the other.

I popped a scope on the antenna of the remote control and was surprised to find that it appears to be permanently transmitting.

It transmits a sequence of pulses and when you push a button, the sequence changes/pulses get faster/PW gets narrower…. Not sure which but you can see changes. Its just very suprising from a battery life point of view, that it permanently transmits.

I’m not really sure if this is a fault or just the way it works….

The only part that does work is the voice over remote function. Push the button, talk onto the remote and voice comes out of robot. And I’m sure that bit DIDN’T function when I first got him…although all the other functions did work….and now don’t…

I also found the tray for Omnibot 2000 so have tested it with a 6 volt supply and have now stripped it down ready for cleaning and reassembly.

Looks like Omnibot is coming apart again so that I can try and figure out whats up with him. BLURGH!!!!

Not All MP3 / CD to Cassette Adapters Are The Same

Cassette adapters that allow you to plug your mp3 player into your car cassette deck are a cheap and viable alternative to buying a new sound deck with a media port included however I couldn’t believe the difference in sound quality between some of these units!

I started off with a cheap unbranded universal adapter that I picked up from Asda (I say cheap….It was actually £7 and have since found the same ones on line for like £1.50).

I thought that these devices were pretty simple and therefore there wouldn’t be much difference between one manufacturer and the next. Was I totally wrong!

The cheap adapter suffered from several issues:

1. An annoying background hiss even at the lowest volumes
2. The Bass would completely disappear at higher volumes leaving tinny treble sound
3. the sound output was biased towards the left hand side of the stereo output meaning I had to offset the car stereo balance to compensate.

So I decided to do some research on whether I could get a better adapter.

I found this helpful review http://www.ilounge.com/index.php/reviews/entry/fall-2005-cassette-tape-adapter-shootout/ from back in 2005 which named the Sony CPA-9C adapter as the best of the bunch.

I then found a later review on the same website http://www.ilounge.com/index.php/reviews/entry/philips-ph2050w-mp3-cd-cassette-adapter/ which named the Philips PH2050W as an even better adapter.

A quick google and I found that the price of these was around £12 except for one seller who was selling two brand new ones for £6??!! (Cheaper than the “Cheap” one I owned and a spare one included!).

I ordered and plugged in and WOW, what a difference! No background hum, No left right balance offset, big deep booming bass and immediately noticeable sound quality improvement.

The Philips PH2050W cassette adapter is by far the best adapter to use. This technology is getting old now and is no longer being developed but if you do have cause to require one, get on google and track a Philips unit down. Its well worth it!

Why is diagonal movement faster than straight movement in old arcade games / 8 bit computer games

I am talking bout real old skool games here, like early 80’s arcade stuff and old 8 bit computer games, but on a lot of them if you had a guy on the screen and you ran straight up, down, left or right you’d move slower than if you moved diagonally.

The issue sounds pretty odd but it’s easily answered and can be proved using Pythagoras Theorem.

If you push the left button, your guy on the screen moves 1 pixel to the left say, and if you push the up button your guy moves 1 pixel up the screen. Pretty straight forward yes.

Now if you push left and up at the same time then your guy moves up-left diagonally. This means he’s moved one pixel left and one pixel up in one move. The actual diagonal distance he’s travelled isn’t 1 pixel though, it’s actually just over 1.4 pixels, just like if you had a right angled triangle and the two shorter sides were 1 metre each then the hypotenuse would be just over 1.4 metres.

This means distance wise that every three straight the guy has travelled 3 pixels, but every three diagonal movements the guy has travelled over 4 pixels, hence why running diagonally gives you an advantage in old computer and arcade games, although usually the enemies had the same diagonal advantage too.

How to fix it? Well when you move diagonally, instead of shifting the guy one to the left and one up, shift him 0.7 to the left and 0.7 up and this will make the hypotenuse about 1. Of course ths screen itself can only display in whole pixels and will round up but as long as you don’t round up the actual x and y co-ordinates of the guy then he’ll skip a move every so often which slows him down to normal pace.

So why wasn’t this built into old arcade and computer games….Well there are three possible reasons:

1. It just wasn’t noticed to start with. (Unlikely)
2. It was noticed but people couldn’t be arsed to add the extra code to make it right.
3. Due to limited memory, there wasn’t enough space to add the additional code so programers just lived with it.