Major Psion Surgery

[Ed_Ca22]

I work largely in robotics and hence have a lot of experience with embedded systems development. Its gradually been dawning on me over the years that the only way I will ever have the perfect PDA is if I make it myself. This sounds like madness, but my perfect PDA would basically be an updated 5mx or Revo, as I imagine most of this sites readers would agree. Check out the gumstix - its a tiny embedded Xscale ARM processor at 200 or 400 MHz. I've been working with these recently and am beginning to seriously consider designing a custom PCB for a gumstix that would fit inside a 5mx case and give us everything we could want - compact flash, USB host and client, built in charging circuit, bluetooth, irda, serial, reliable internet and high quality sound and you could even add a colour screen (this still requires research to find one the correct size). You'd get the gorgeous 5mx form factor, keyboard etc, but with an updated internal system. The OS would be linux (apparently windows CE is possible - but I'd rather load all my psions into a car crusher and then launch them into space than run THAT OS).

I've also been working behind the scenes to create a new lightweight linux UI that takes the best parts of EPOC and advances on them, as well as finding Linux replacements for EPOC programs. I was at the alpha-beta stage with this when I lost almost all my belongings (including all the work for my MEng) in a theft a couple of months ago, so unfortunately lost almost all this work (I've had the most stressful time of my life!) - but I have begun to pick up the pieces and start work again. The software is C++ in X window using fltk.

Interested? This is a fairly big project - I'm no one man miracle worker (and I'm an completely broke student) but it can be done. If anyone has relevant experience in embedded hardware or linux C++ I'd like volunteers to set up a project to get this done and really keep the psion alive. It may be easier to start with the netBook and then advance to the 5mx later. Other expertise will also be needed if it works out - web site development, testers, ideas people etc - all are welcome.

Thoughts?

Ed.

[ohsix]

For what it's worth - I'm just a simple Psion user - love it, but have never gotten into e-mail or web use. Although most of my friends do, I've never felt the need to be connected 24/7 when traveling.

My main concern with your description is the battery thing. I had such bad luck with the Mako battery charging that I'm very down on rechargeable battery systems. I *like* the 2xAA alkaline system of my 5mx - no extra cable/adaptors to carry on bicycle trips, and can buy AAs almost anywhere in the world.

But I wish you luck. Maybe someday I'll meet a Psion expert who will get me set up for e-mails. But then I'd have to carry some sort of modem, wouldn't I?

Keith

[Ed_Ca22]

My main concern with your description is the battery thing. I had such bad luck with the Mako battery charging that I'm very down on rechargeable battery systems. I *like* the 2xAA alkaline system of my 5mx - no extra cable/adaptors to carry on bicycle trips, and can buy AAs almost anywhere in the world.

I meant an in-built charger for the AA batteries - hopefully they will be powerful enough. The idea is to change as little of the 5mx as possible - its already going to be an expensive project, and mechanics are always the worst. It would be nice for the PCB to be a drop in replacement for the 5mx mainboard, just swap them over and go!

Fortunately I have some gumstixs to play around with - I need to design a PCB and buy parts, which is both time consuming and expensive. I also need to decide from the start whether to use a colour LCD or stick with the current 16 colour psion display - since this will be annoying to change if I later want to update. I will try to leave the design open so that a different LCD could be used later, as I cant afford to buy an LCD at the moment (or for the forseeable future - I am but a poor broke student!).

The nice thing about using gumstixs is that they run Linux and have most of the annoying parts of embedded development done for you - mounting the tiny processor, flash and RAM parts, crystals, etc is all done for you and most hardware you can add is supported instantly by linux. This leaves freedom to just add the peripherals you want and go.

But I wish you luck. Maybe someday I'll meet a Psion expert who will get me set up for e-mails. But then I'd have to carry some sort of modem, wouldn't I?

Unfortunately, yes. My one big gripe with the 5mx is that internet has never really worked too well - web browsing is almost useless, and although emails work the amount of hardware you need to carry around is prohibitive. This would also be solved by this upgrade, using bluetooth and wifi.

This is one of those projects that may never see the light of day, Im afraid - it all depends on me getting time to do it. I'm hoping that now I've opened my big mouth about it to everyone I'll feel more pressured into finding time for it. But if there is anyone with experience or who can offer support, suggestions, help programming the new UI or help in any other way, I could really use it. If there is a reasonable response I'll try and get round to starting a website where we can lay out ideas and coordinate efforts.

Cheers,

Ed.

[bob_stra]

Wow Ed - that's just about *the* perfect machine for me.

I have no skills to offer you, though I wish I did. Presumably you know about the precompile Psion Linux Kernal (if that's any assistance?)
http://linux-7110.sourceforge.net/

Look - is there anyway we can keep in touch with you? A mailing list or a website? Please don't say "it may never see the light of day" because I want one of these machines you're proposing - and I think a lot of others will too.

Re: Colour of Gray-Scale. The main issue with the 5's is that the black on green is not that visible. If you do go gray scale, how about a high(er) visibility white on black? It should take less juice than an colour LCD screen but be nearly as legible? What do you think?

[Ed_Ca22]

Re: Colour of Gray-Scale. The main issue with the 5's is that the black on green is not that visible. If you do go gray scale, how about a high(er) visibility white on black? It should take less juice than an colour LCD screen but be nearly as legible? What do you think?

The idea of leaving it greyscale is that the existing psion screen can be used and thus reduce the cost - it is not cheap to produce multilayer SMD circuit boards on a small scale, then there is the gumstix (around £100) and a colour LCD would up the price more (assuming I can find one the correct size). I'll try to make a prototype circuit board (PCB) first - this will cost the most, then further boards could be made in batches.

If a suitable white on black screen could be found, great, but I'm guessing the expense isnt justified over spending a bit more on a colour display.

I will try to leave all the LCD pins available on some simple connector so that different LCDs can be tested, while also having a standard 5mx LCD connector to allow an easy/cheap upgrade. You've got to walk before you can run!

Presumably you know about the precompile Psion Linux Kernal (if that's any assistance?)
http://linux-7110.sourceforge.net/

Look - is there anyway we can keep in touch with you? A mailing list or a website?

If you go to http://linux-7110.sf.net and then go to members you should see me as a project admin and you can get me via my sourceforge email there (I'll follow up any messages using my personal mail account though).(Thats kernel btw).

Maybe I will set up a sourceforge website for the project, but I hate writing web pages (dont mind doing content) so if you can help out there I'd be grateful!

Cheers,

Ed.

[cshandley]

Originally Posted by Ed_Ca22

Its gradually been dawning on me over the years that the only way I will ever have the perfect PDA is if I make it myself. This sounds like madness, but my perfect PDA would basically be an updated 5mx or Revo

Not madness at all! It gradually dawned on *me* 5 years ago that the only way I would ever have the perfect programming language was if I made it myself - and only now am I close to having something useful.

I would love to see a new PDA that used the shell of a 5mx, although it does sound like a damn big job. Unfortunately I can't offer any help, although perhaps you could try speaking to the people still making that 5mx Pro "clone".

[Stargazer]

I'd be keen on a 5mx upgrade also but since the screen is its main weakness, it really would need to be included (decent backlight plus colour). A £200-300 price for a total makeover would be the limit cost-wise in my case. Having the option to boot EPOC (for retrieval of data, nostalgia, etc) would be highly desireable also, even if it means losing access to the new features.

For batteries, I'd skip the charger - it rules out using non-rechargeable AAs in an emergency and it would need to be reasonably sophisticated (Delta-V or Delta-T) to be able to accommodate all capacities.

[Ed_Ca22]

I'm afraid upgrading the LCD is going to have to be left for the time being - especially as I've just worked out how to connect the gumstix up to any one of the 5, 5mx or Revo displays, which means the upgrade could potentially be for any one of these. Adding an LCD means not only buying something expensive and hard to find, but also something exactly the correct size, which I dont have too much time to find - if you want to search for a colour LCD, 640x240 and about 160x60x5mm in size (rough estimate - will measure the LCD more with a vc at some point) I'd be happy to have a look at your findings - almost any LCD can be connected to the gumstix.

As to the batteries, the first thing to check is that AAs will last long enough for the machine, otherwise it may be necessary to go for Li-Ion. The gumstix generally needs 4.5-5V for power, so we may have to ditch the AAs anyway I'm afraid. Personally I think an in-built charging circuit would be really nice, but I'll definently be providing some way to turn it on and off. I havent really looked into charging circuits yet - what are Delta V and Delta T? Power is an issue - the LCD itself needs 20V, so I need some sort of step up converter anyway - maybe I will be able to use AAs, who knows?

So far I've got the LCD, Touchscreen, Audio, Bluetooth, irda, Serial and compact flash circuits designed (or stolen from gumstix.org), and have only four chips in total (and some 20 capacitors/resistors and 1 crystal - and of course a load of connectors). Touchscreen and audio (stereo output AND input ) are managed by a single chip (Philips UCB1400) which is cool, although I havent worked out where there is room for phono sockets yet.

I still have to design the power system (which I'll probably leave until I've tested everything else), sort the keyboard out (which should be pretty easy), and work out how in h**l I'm going to connect the backlight up - I think the only way I'm going to get an inverter without having to learn a lot about the 5mx backlight is to steal the inverter circuit (HV823) from the 5mx itself, it has all the correct inductors etc already there, although I once replaced the backlight inductor from a series 5 with wire wrapped around a piece of wire insulation and it worked just fine! But I'm also going to be taking the compact flash, battery, rs232, keyboard and LCD connectors from the psion, so hey, why not steal some more parts while I'm there?

If I can keep the circuit really small and do some nice PCB design work I may be able to keep the PCB down to single or double sided - which isnt too expensive to manufacture. It depends on how many I have to order, but single sided PCBs are dirt cheap (can be made at home) and if I could get 20 people who all want one I could probably get double sided PCBs for about £20-30 (I'm just guessing though). Multi-layer PCBs are much much more of a problem - especially as I've never designed one. So along with a gumstix connex ($109 - $169 depending on speed of 200 or 400MHz and built in bluetooth or not) and a few parts the total price should easily be less than £200 - hopefully more like £100.

It would also be nice to add a memory card slot - sd,xd,mmc, something like that - MMC is supported by the gumstix but I'm not sure it can be used at the same time as compact flash. It would be great to have a memory card slot under the backup battery compartment door. This would be good especially since there is only 16 MB of flash memory inside the gumstix and I'm not planning to add any - more will be needed in order to have a working system, but that would prevent the cf being used for wifi cards etc. If a memory slot could be added the problem would be solved. We'll see.

For the revo, since I dont think there is much chance of finding room for a compact flash slot (and since I would have to design a whole new PCB anyway) it might be best to use a gumstix basix. To clarify there are two types of gumstix, connex and basix. Basix has an MMC slot built in, which would be nice on the Revo, but does not have the extra plug that allows you to add compact flash. I think the revos charging circuit is built into the battery compartment, so batteries would be easy to sort out.

Hmm. Well maybe some kind of built in storage is needed?

I ordered a gumstix connex 400MHz with built in bluetooth (yeah, the best one) for testing purposes on Friday (when I say 'I', I mean my supervisor, and when I say 'testing purposes' I obviously mean work purposes...but fortunately I can take hardware home to 'work' with). So I'm going to start sorting out a test system and ordering some parts in the next few weeks; I'll keep everyone posted.

[Ed_Ca22]

I've decided to just go on using this thread as a place for ideas, feedback, discussion as I cant be bothered to set up a website and everyone who is interested is already here anyway.

Cheers for the interest,

Ed.

btw, anyone know what psion are going to say if I start selling these boards? I cant afford a legal battle... (and dont get me wrong - I am NOT in this for the money).

[Stargazer]

Originally Posted by Ed_Ca22

I'm afraid upgrading the LCD is going to have to be left for the time being - especially as I've just worked out how to connect the gumstix up to any one of the 5, 5mx or Revo displays, which means the upgrade could potentially be for any one of these. Adding an LCD means not only buying something expensive and hard to find, but also something exactly the correct size, which I dont have too much time to find - if you want to search for a colour LCD, 640x240 and about 160x60x5mm in size (rough estimate - will measure the LCD more with a vc at some point) I'd be happy to have a look at your findings - almost any LCD can be connected to the gumstix.

This was discussed in the Colour screen Psion 5MX thread - there appeared to be some prospect of this before the thread went quiet. It may also be possible to accommodate a slightly larger screen by shrinking the left-hand/bottom command strips.

Originally Posted by Ed_Ca22

As to the batteries, the first thing to check is that AAs will last long enough for the machine, otherwise it may be necessary to go for Li-Ion. The gumstix generally needs 4.5-5V for power, so we may have to ditch the AAs anyway I'm afraid. Personally I think an in-built charging circuit would be really nice, but I'll definently be providing some way to turn it on and off.

The big problem with Lithium Ion batteries is that they have a lifespan of 2-3 years, regardless of whether you use them or not and they require extra circuitry to prevent overcharging. Even if you do manage to develop a solution here, could you guarantee its continued availability 5-10 years in the future? AA batteries have the advantage of always being available (with the capacities of NiMH rechargeables steadily increasing) so I'd suggest that having these, even with half or a third of their previous lifespan would be preferable to most.

Originally Posted by Ed_Ca22

I havent really looked into charging circuits yet - what are Delta V and Delta T? Power is an issue - the LCD itself needs 20V, so I need some sort of step up converter anyway - maybe I will be able to use AAs, who knows?

Delta-V rechargers monitor the battery voltage to determine when to stop charging, Delta-T monitor temperatures. This allows them to handle rechargables of differing capacities without overcharging.

Originally Posted by Ed_Ca22

So far I've got the LCD, Touchscreen, Audio, Bluetooth, irda, Serial and compact flash circuits designed (or stolen from gumstix.org), and have only four chips in total (and some 20 capacitors/resistors and 1 crystal - and of course a load of connectors). Touchscreen and audio (stereo output AND input ) are managed by a single chip (Philips UCB1400) which is cool, although I havent worked out where there is room for phono sockets yet.

Sounds promising - I presume you will be including headphone/microphone socketry also? Would wifi be a possibility?

Originally Posted by Ed_Ca22

I still have to design the power system (which I'll probably leave until I've tested everything else), sort the keyboard out (which should be pretty easy), and work out how in h**l I'm going to connect the backlight up - I think the only way I'm going to get an inverter without having to learn a lot about the 5mx backlight is to steal the inverter circuit (HV823) from the 5mx itself, it has all the correct inductors etc already there, although I once replaced the backlight inductor from a series 5 with wire wrapped around a piece of wire insulation and it worked just fine! But I'm also going to be taking the compact flash, battery, rs232, keyboard and LCD connectors from the psion, so hey, why not steal some more parts while I'm there?

Rather than an electroluminescent backlight, how about using LEDs? This should avoid the need for an inverter. Alternatively, seeing what the Netbook uses may help (probably too power-hungry though).

Originally Posted by Ed_Ca22

It would also be nice to add a memory card slot - sd,xd,mmc, something like that - MMC is supported by the gumstix but I'm not sure it can be used at the same time as compact flash. It would be great to have a memory card slot under the backup battery compartment door. This would be good especially since there is only 16 MB of flash memory inside the gumstix and I'm not planning to add any - more will be needed in order to have a working system, but that would prevent the cf being used for wifi cards etc. If a memory slot could be added the problem would be solved. We'll see.

This would require changes to the Psion case though, which presumably would make the upgrade much more complex to do - including more internal RAM may be an easier option or maybe even doubling up on the CF-card slot (though this would be tricky too).

Originally Posted by Ed_Ca22

So I'm going to start sorting out a test system and ordering some parts in the next few weeks; I'll keep everyone posted.

Look forward to hearing how things progress!

[RichardQvS]

Hi Ed,

Maybe it's best to send them an email with your ideas and ask for their permission, you might never know what they say.

Just last year I had come across some special Psion service manuals, which should not be used outside Psionbuilding. After some emailing, I was very happy to get the OK to send them to any interested Psionfan (with some exeptions/conditions). Now in our Psionsociety, many enthousiast are glad to have them for reference when searching for parts or for repairing them.

If you need an emailadress of my contactperson, please send me an email.

Many Psiongreetings from the Netherlands,

Richard van Stappershoef

[Ed_Ca22]

The big problem with Lithium Ion batteries is that they have a lifespan of 2-3 years, regardless of whether you use them or not and they require extra circuitry to prevent overcharging. Even if you do manage to develop a solution here, could you guarantee its continued availability 5-10 years in the future? AA batteries have the advantage of always being available (with the capacities of NiMH rechargeables steadily increasing) so I'd suggest that having these, even with half or a third of their previous lifespan would be preferable to most.

I am aware of this problem with Li-Ions. I would probably use the same cells used in the netBook - they are also used in many laptops and should therefore be readily avalable. Unfortunately changing them is not easy (or entirely safe) and cells themselves cant be bought in the UK.

Delta-V rechargers monitor the battery voltage to determine when to stop charging, Delta-T monitor temperatures. This allows them to handle rechargables of differing capacities without overcharging.

I was actually intending to use both, voltage level gives a good idea of remaining capacity and a temperature sensor can be used to prevent over charging - especially for Li-Ions.

Sounds promising - I presume you will be including headphone/microphone socketry also? Would wifi be a possibility?

Both an internal speaker/mic will be used in the same configuration as the 5mx already has (I will try to utilise the existing record/play etc buttons) and sockets. I just need to find where there is room to drill two holes in the psion case.

Wifi is probably not possible - compact flash would have to be used for this. Wifi would require me to work out how to connect up a wifi chipset, which is not simple and will make the PCB more complex. I favour bluetooth as it is very low power and can be connected to a serial port very easily.

This would require changes to the Psion case though, which presumably would make the upgrade much more complex to do - including more internal RAM may be an easier option or maybe even doubling up on the CF-card slot (though this would be tricky too).

Adding double CF is not really practical, but a working linux system with space for programs will need more than 16Mb of flash available. Adding more RAM is very tricky, plus that will not give more permanent storage. If I do add more intenal storage it will be in the form of an SPI or I2C bus based flash chip. The SPI bus will allow an internal storage chip and/or an SD card slot, either of which would suffice. This also allows the compact flash slot to use a wifi card or vga out or whatever. One possibility is to have a fully blown 16 bit PC Card slot instead of a cf slot, which gets a huge range of peripherals like hard disk controllers/cd rom drives, network cards etc available to us.

Rather than an electroluminescent backlight, how about using LEDs? This should avoid the need for an inverter. Alternatively, seeing what the Netbook uses may help (probably too power-hungry though).

I dont think LEDs will be too good, as they will leave dark patches or areas on the screen unless they can be mounted directly behind - and I dontthink there is room for that. I'll look into it though. All kinds of backlights (except LED) need an inverter to provide high frequency power at a very low current for the backlight - the netBook is no different except that it has a better white backlight (as do most colour screens). The netBook backlight is a completely different specification to the 5mx one, and thus needs a different voltage, frequency etc supply. So I may be better off just using the IC currently on the 5mx - especially as I dont know the exact specifications of the backlight and the inductors used in backlight inverters are difficult to get hold of. There are some generic backlight inverters that can be bought and set up to work with a given backlight, however they are fairly expensive and may not be small enough for the 5mx.

Just last year I had come across some special Psion service manuals, which should not be used outside Psionbuilding. After some emailing, I was very happy to get the OK to send them to any interested Psionfan (with some exeptions/conditions). Now in our Psionsociety, many enthousiast are glad to have them for reference when searching for parts or for repairing them.

Thats interesting, as psion are notoriously difficult to get information out of! Having said that they have provided most of the 5mx specs to openpsion, its just that we could really do with the netbook ones. I'll send you a mail.

Thanks and regards,

Ed.

[Stargazer]

Originally Posted by Ed_Ca22

Wifi is probably not possible - compact flash would have to be used for this. Wifi would require me to work out how to connect up a wifi chipset, which is not simple and will make the PCB more complex. I favour bluetooth as it is very low power and can be connected to a serial port very easily.

Bluetooth certainly should be better for power consumption - the problem with using the CF slot for wifi is that the card needs to be able to work with the cover closed (unless you have plans to remove it completely).

Originally Posted by Ed_Ca22

Adding double CF is not really practical...One possibility is to have a fully blown 16 bit PC Card slot instead of a cf slot, which gets a huge range of peripherals like hard disk controllers/cd rom drives, network cards etc available to us.

You'd probably be better looking at ExpressCard (the followup to PC-Card) since this offers a smaller form factor but this would likely be as difficult. Perhaps an alternative approach would be to replace the serial port with a higher speed connector (USB 2.0 perhaps?) and look at providing a "docking station/expansion cradle" which could then handle multiple CF/Expresscards.

Originally Posted by Ed_Ca22

I dont think LEDs will be too good, as they will leave dark patches or areas on the screen unless they can be mounted directly behind - and I dontthink there is room for that.

A good reflector behind the screen should handle this - though it would need to be less reflective near the LEDs in order to ensure even brightness. For the LEDs themselves, a side-emitting Luxeon or a 2mm Luxeon Portable would seem likely candidates.

[Ed_Ca22]

Bluetooth certainly should be better for power consumption - the problem with using the CF slot for wifi is that the card needs to be able to work with the cover closed (unless you have plans to remove it completely).

Yeah, the cf door was designed out ages ago - it doesnt look quite so pretty but if you're really concerned it isnt too hard to make a neatly cut hole in the door I suppose! Adding a PC card slot would be really nice but I dont think the batteries would take it for long, plus you'd have to cut the case a bit to make room for it - and I'm not convinced there is room for it even then. I'm starting to really like the idea of a modded revo - they are so portable.

You'd probably be better looking at ExpressCard (the followup to PC-Card) since this offers a smaller form factor but this would likely be as difficult. Perhaps an alternative approach would be to replace the serial port with a higher speed connector (USB 2.0 perhaps?) and look at providing a "docking station/expansion cradle" which could then handle multiple CF/Expresscards.

ExpressCard is simply not an option - the XScale processor on the gumstix has built in compact flash/PC card support - expresscard is a completely different bus and would require some kind of interface chip - its also probably way too fast for a 400MHz ARM.

There will be a USB 1.1 client port (12Mbps) - allowing you to plug the psion in to any computer and make it appear as a usb hard disk, or alternatively a driver can be loaded on the pc (whether windows, linux or mac) and the usb connection will act exactly as if it were an ethernet connection, as far as the pda is concerned.

I have also just checked out a very nice looking usb 2.0 host controller (td242lp) which I could probably add to the design - giving 2 usb ports if there is room anywhere on the case. Also there are constraints on the PCB and whether it can all be built into one or two sides. It would be very nice to have usb host - virtually all our problems would be instantly solved!

A good reflector behind the screen should handle this - though it would need to be less reflective near the LEDs in order to ensure even brightness. For the LEDs themselves, a side-emitting Luxeon or a 2mm Luxeon Portable would seem likely candidates.

Thats a good idea - the screen would look really nice without the el backlight (trust me I've tried it - you can see through it if there is enough light). I'll have to see if theres room.

I'm still hoping other people will join in the fun!

Cheers,

Ed.

[Donaldr]

http://www.flextronics.com/manufactu...abrication.asp