Things I'm Planning for my A600

[LuMan]

I had a bit of an idea today for a new project. As I've managed to blag myself another A600 off the interweb tat bazaar that is eBay (for a winkle over 16 quid ) I thought of putting my old, beaten up A600 into some sort of laptop type thing. I know this has been done before, but I'd like to make my own mark on something a little unique.

Here's the (rather long) plan:

1. Mobo - Self explanatory. I'll simply remove this from the A600 and use it as the motherboard
2. Power - 12V Li-Po laptop battery (or equivalent) from another laptop. This means I can use the bespoke charger and plugs. I'll knock up a boost/trickle circuit to keep things juiced up.
3. FDD - This will be removed (see #4)
4. CF drive - This will be placed towards the edge of the case so it can be formatted and loaded with OS, WHDLoad and other stuff. The idea is that I put the environment together using my other A600 and just pop the CF card over.
5. Keyboard - The existing one is too bulky so I'll re-etch a smaller membrane and cross-map it to an old laptop KB. Obviously some of the keys will be redundant (such as the keypad keys on the Fn extensions) but all the Amiga keys will be represented in some way.
6. Mouse - I'll either use a touchpad or use an old Amiga mouse innards to make a trackball device. This will be auto-switched and piggy-backed onto the existing port so I can plug in two joysticks if necessary.
7. Sound - I'll drop in a very small 5V amp circuit - probably powered by the FDD header - and feed a couple of small speakers either side of the screen.
8. Screen - 10"-12" LCD TVs are cheap as chips now, so I'll butcher one and use the panel and associated composite (or RGB if available) circuitry. The screen should be narrower than the mobo so I'll have a couple of inches for the screen-mounted speakers.
9. Case - The tricky bit! I intend to build a sheet aluminium sub-chassis to keep everything stiff and then build a box out of high impact perspex or some form of sheet modelling plastic. Either way, the plastic is just to absorb shocks and cover blemishes (it's easier to form than aluminium!!). The chassis will be connected to the aluminium screen frame via hinges (again, to keep it stiff). Obviously insulation will be the order of the day!!
10. Future - If I get this far, not only will I be amazed, but I'll see how much power it draws and then look at adding USB or 030/xx and RAM.

I'm putting together a workbench in my playroom this week, so I'll be even more keen to get to work on this. Of course, I'll add photos as I go along

If anyone has any advice or ideas they want to chip in, then please feel free. Beer will be given up to any good ideas that I use

[fitzsteve]

Look forward to seeing the pics, sounds like a very involved and complex project.

Good luck!

Steve.

[LuMan]

Hi Steve - Thanks for the interest. Looks like my post was moved - I was hoping to keep it hidden away in OT, but now it's in a more popular area I'll REALLY have to pull the stops out in case it goes pear-shaped HAHAHA

The future Mrs LuMan has sanctioned the project (including the enhancement to my playroom) so the project is a definite GO! I'll document all work and post an archive on LuWeb (if I remember ) and I'll keep it as simple and modular as possible. The A600 is perfect for potable Amiging so I hope others will join he bandwagon!!

[8bitbubsy]

Keep in mind that you need not only +12v, but also +5v and -12v. You can generate this with some resistors, diodes and capacitors I think, and a voltage regulator for +5v.
But I'm unsure if you can deliver enough ampere, especially on the +5v after the voltage regulator....

[Stedy]

Hi,

One of these will probably work well for the power supply:
http://www.mini-box.com/M3-ATX-DC-DC...C-Power-Supply. It operates over a wider range than a picoPSU and will supply all the power rails you need for the A600. You should be able to hook it up to a Laptop type battery, after the Low voltage lock out circuit.

Please be careful with LiPo batteries, only use the correct charger otherwise you will have flames (look on youtube for LiPo overcharging).

A number of trackpads, even on more modern laptops use the PS2 interface. Never tried it but one of the PC to Amiga mice adapters may work, if you can decipher the pinout.

For the screen, take care with the LCD backlight circuit and power arrangement. It is easy to get interference on the video signals.

Hope the above helps.

Ian

[LuMan]

Thanks for the advice, guys. Much appreciated.

After doing some initial planning I've decided on a 2-phase approach. Firstly I'll make a portable device powered from the mains and then work out the battery side of things after I've established current draw for the computer and the screen.

@Stedy - You're right. LiPo can be a bit dangerous in the wrong hands - or even with the wrong voltage!! - but batteries are small and light. I'm looking into charging solutions while carrying on with the main build, but as it's 'phase-2' I can kick back on it a while.

I've already started the tear-down of the a600 and started retr0briting the keyboard (for another project). I'll stick the progress in another, dedicated thread.

[jimbob]

Hi Luman, did you make any progress with this? I'm contemplating some hackery and was wondering if you could elaborate on how you plan to etch a new membrane?

I'd also like to hear what you found in the way of suitable LCDs, though I think I'm looking for a smaller size than you.

[LuMan]

Hi Jimbob - I haven't actually forgotten about this, but it took a back seat due to another major project (getting married!! ). However, the long Winter nights mean more hackery and a couple of transactions off eBay and some bloke at work have given me a lot to do to fill the void.

So far I've got a skeletal A600 running with a 2.5" drive, connected to an even more skeletal 9" LCD TV. The electronics in the TV are so minimal it was easier to hardwire a SCART solution and not bother with any complicated video-porting. I've even used the TV's speakers for the sound

Another lucky thing was the TV running off 12v. I've seen a number of TVs that do this, so I ran a feed from the A600's PSU. The TV has a very low draw and the system runs nice and stable. The downside is that I did this some months ago and the whole lot's up in the loft

The 'to-do' list is to get a decent briefcase to house the finished article and get a smaller PSU that I can shoe-horn into the casing and have just a kettle-lead input for power on the side of the case. Oh yes, I need to post pictures.....

WRT etching my own kb membrane - I found a complete keyboard and a new membrane on eBay, so I'll probably go with those. However, a quick bit of Googling led me to some services that can 'print' circuit boards onto acrylic for flexible solutions. It's not particularly cheap, though. Having said that, it may be worth getting a quote for a couple of hundred and teaming up with other board members to get a realistic price... Hmmm....

Thanks for the interest - it's inspired me to finish the project again

[jimbob]

Congrats Luman, now you have a ring on her finger you can reveal your amiga habit

Good to know there are small screens available that require minimum adjustment to work with amiga RGB.

I had a quick search for flexible pcb makers, much of what came up were those sites with contact details & pictures of jet pilots and warships etc, not hobbyist scale stuff! I did find this though -

http://www.instructables.com/id/DIY-...nted-Circuits/

Not sure how you go about doing those graphite contacts though?
I thought you had in mind mapping a non amiga keyboard into the A600 keyboard controller. That's why I asked as I'm also thinking of wiring something different into the keyoard controller.

Look forward to seeing your finished A600 laptop

[LuMan]

Thanks, jimbob. Luckily she was already aware of my 'habit' before I proposed. A case of 'love me - love my Amiga'!!

The instructibles site is pretty good, but it's worth bearing in mind that there are a couple of 2-layer tracks on the membrane for a couple of the keys. Not tricky to do, but an extra bit of work.

WRT connecting another keyboard, I reckon the simplest way is to use a PIC processor and re-code for the input/output. I bought one ages ago for my A1200T which uses the old AT (DIN5) style of PC keyboard. At the same time Amiga Format were running an article on PIC programming and I toyed with upgrading the AT connector to a PS/2 type. In the end I didn't bother and have recently bought a Lyra USB adapter. Much better

PICs are dead easy to code for and you can get a full kit, including PIC, from Maplin for about £50. Careful, though - once you get started you'll be making all manner of custom IC chips!!

I've managed to get my hands on a Samsonite briefcase which looks just right for the project. I'm getting a new Dremmel for Christmas, so I think the New Year will be ripe for a prototype build.