Handheld ZX Spectrum

[DanielBull]

It seems this project is now far enough along that I actually have some things to show you, so here we go

I'd been wanting to build a hand held ZX spectrum for a while and was thinking of using a Raspberry Pi running FUSE (Free Unix Spectrum Emulator) but the Pi was just too big, so when the Odroid W was announced complete with LiPo circuits I decided now was the time, and started making layouts using just colour printouts of the Odroid as it wasn't yet available (this was also before Ben Heck had the idea and started his Spectrum).

If you look at the photo below I have a PiTFT screen (actually running from a Raspberry Pi at this point) with some custom PCB's either side and below, followed by two DECT portable phone batterys some old Dell laptop speakers, the printout of the Odroid and a USB sound card dongle which was to power the speakers (eventually I ditched this as I wanted to use the USB for WiFi).

Ironically one of the things which took the longest was working out a set of keys which could make up the controls and work on the maximum number of games. This is because early Spectrum games rarely used the same keys and joysticks were not common and came in a few different types.

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[DanielBull]

Next I did some designs using 123D Design for my 3D printer. Its in two pieces a front and back both as compact as possible to keep it small and light.
Those of you that know the spectrum will recognise the space for the stripe on the front...

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[DanielBull]

Next I printed the back piece and started to layout the components, thankfully they all fitted!
It did actually take me two attempts as I had problems with warpage on the first try, however this gave me a chance to tweak the layout to perfection.
The small PCB above the right speaker is actually for a power/reset button which is rear facing.

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[DanielBull]

Next I started wiring and quickly realised that due to the large number of buttons (all the GPIO's are used!) this thing wasn't going to come apart very easy. And since my original plan for upgrading the software was to remove the SD card and stick it in a Pi it was obvious this wasn't going to be practical. Thats when I decided to ditch the idea of the USB soundcard (to free up the USB) and instead use a small amp for the speakers (the original reason for the soundcard was the output from the broadcom wasn't enough to drive the speakers directly). Freeing up the USB meant I could then install a WiFi dongle and access the project remotely for upgrades.

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[DanielBull]

Next I took a standard Edimax WiFi dongle and dismantled it, preparing for it to be mounted on the Odroid.

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[DanielBull]

Finally I wrapped it in Kapton tape (something those with 3D printers will likely have lying around as we use it on the print beds) and mounted it on the Odroid, hooking it up to the USB, then put the whole lot together.

It works perfectly by the way

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[DanielBull]

My final pictures for today are of the inside of the front.
Unfortunately the front like the rear had terrible problems with warping (which I've now solved so I will print it again soon) but it was good enough to test out the inside and make sure the components fit. In here you can see the screen, the back of the control boards and the top microswitches.

Anyway I hope you like my project, there's been a LOT of hours so far but it seems to be worth it, the Odroid W is a fantastic piece of kit!

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[odroid]

Great project!
I love the stereo speakers and stereo batteries.
I think you can play tons of ZX games for 2~3 days without sleep.

BTW, can you tell me the part number of shoulder switches?
It seems to be very durable and reliable.

[DanielBull]

The shoulder switches are from ebay:
http://www.ebay.co.uk/itm/5x-Microswitc ... OC:GB:3160
Looks like the part number might be V5 SW052 MS-118, there is nothing written on them. I got the heavy force version to make sure they spring back properly.

Yes I'm getting really good life out of the batteries, they are two packs of 2x950mAh which totals 3800mAh. I've actually measured them at 3400mAh in real life. So if we say 3400mAh at ~4v thats 13600mWh which works out at 2720mAh at 5v. Not sure what the Odroid will draw running the emulator but the WiFi is 40mA and the screen the screen is 100mA, so if we say ~150mA for the Odroid that means we are looking at ~9 hours which is very good. I would be happy with 3 hours

[odroid]

Thank you for the valuable information of that switches.

When I played a few GBA games with HDMI out, it consumes about 160~170mA.
So you estimation seems to be very close to the real world.

[fpp]

Very impressive indeed !
I like the trick with the USB dongle, but what I really dream of is to be able to create a custom case like yours for my digital audio player (described in the "Success story" thread) !
Unfortunately I haven't even seen an actual 3D printer in real life, and the current prices make it hard to justify for such a hobbyist use...
Also, I suspect that for someone who has never used CAD software & concepts (much less 3D CAD), the learning curve to create something usable much be quite daunting.

[DanielBull]

I got a 3D printer kit because although I have quite good mechanical and electronic skills I didn't know much about 3D printing. The kit was a Mendel 90 by NopHead and cost £500+VAT (UK). I don't regret it at all, it was a fantastic kit, really well designed and worked first time. Also the building process taught me lots about how they work and now I have even learnt enough to make my own changes and improvements.

I had never used CAD before either and I have to say it did take me quite a bit of free time to learn. A lot of it was wasted as well as I changed packages 3 or 4 times before I settled on 123D Design. It was all worth it in the end though as you can see

[DanielBull]

I liked your digital audio player by the way, it actually looked pretty cool

[fpp]

Thanks for the compliment and the feedback on your own 3D printing experience Daniel !

I'm sure I'll get around to it eventually, but I just have too much stuff on my hands these days.
I realize the best way to get started would be to find a hacker space nearby and learn the ropes there, but I lack the time even for that

[DanielBull]

Quick update on this, its a shot of the front and the buttons fitted (but the screen not fitted).
I moved the controls slightly higher up than in the original CAD drawings to increase the comfort whilst holding.

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[snah]

Very cool stuff Daniel. The 3D print looks brilliant. What printer are you using? Are you using the touch screen PI TFT?

[DanielBull]

Yes its the PiTFT touch screen.
For the printer see above, its a RepRap design called a Mendel90. I bought a kit made by NopHead who is well known in the 3D printing community.
More pics of the printer, the build process, some prints and my various modifications here:
https://plus.google.com/u/0/photos/+Dan ... 545?sort=1
Theres even an old Odroid X case I printed in there

[DanielBull]

Still in rough/fast 3D print mode but its working and playable

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[odroid]

I love the 10 small buttons !

[DanielBull]

Yes thats the number buttons along the top of a Spectrum keyboard. This is because lots of Spectrum games used these on the options screen.

[car.cuevas]

So cool

Congratulations for such a nice project )) !!!

[DanielBull]

Cheers

[fpp]

Really neat ! I wish I could design a custom case like this for my DAP...

[DanielBull]

I just used 123D Design which is free software:
http://www.123dapp.com/design-alt

If you don't own a printer lots of places will print it for you, such as Shapeways.
http://www.shapeways.com/

Although admittedly if you do own one its cheaper and easier to get it right.

[fpp]

Yes, there are ways without a personal printer.
I also found this interesting site : http://www.3dhubs.com/
It shows quite a few people who own one in my close neighbourhood, and are willing to print for others.

I guess the main problem for newbies is to learn to use the software, and then to get the design right without too many iterations

[DanielBull]

Yeah learning CAD took some time. I watched a video by Ben Heck which helped me get started with 123D:
https://www.youtube.com/watch?v=03Ju_LJlU3U

[fpp]

Will do the same, thanks for the pointer !

[SpearUK]

Awesome project!
I am in awe

Really wish I had a 3d Printer but I am finding it hard to work out the differences between them and they seem to range in price from £250 to £3000. Plus I hear some force you to use their own proprietary cartridges which they sell for double or triple the normal price....

[DanielBull]

What are you looking for a self build kit or something that works off the shelf?
Self build kits are the cheapest; if you are in the UK get the NopHead Mendel90 its a no brainer almost everyone recommends it. The other one that's popular is the Printrbot Metal. Its not as good as the Mendel but its cheaper. If you want prebuilt get an Ultimaker2. Thats my opinion anyway and lots of people agree.

[DanielBull]

Hey guys, thanks for putting me in the Odroid Magazine. You should have said you were going to do that and I would have done some better photos and text

[Tronic]

Thank you

[tiyaray]

Exceptionally amazing undoubtedly!

I like the trap with the USB dongle, yet what I truly dream of is to most likely make a custom case like yours for my computerized sound player portrayed in the "Example of overcoming adversity" string.