Whether you owned one or lusted after them on the shelves at Tandy or Dixons, during the late 80s and throughout the 90s, the personal assistant (or PDA) reigned supreme to anyone after a portable computer but not wanting spend the hefty price tag of much larger, more powerful laptops. Covering the history of these devices would cover more than a fair few articles alone and is a little beyond the scope of what we are going to do today.
Last year I was lent a Hewlett Packard 200LX by my friend Darren, who thought I might get a kick out of using this tiny DOS compatible palmtop. As it happens, he was right. Playing around with the 200LX has been interesting to say the least, even leading to the purchase of a Psion 3a for my own personal use.
The HP boasts a chiclet keyboard similar to those found on calculators and industrial equipment and features many of the same functions found on modern keyboards today, such as functions keys and a numerical keypad for quick data entry.
While using the HP, I have to admit I’ve held something of a love/hate relationship for the keyboard. In the beginning I struggled to type on it with any proficiency, often mashing the keys with my apparently podgy fingers. Only by the second week did things begin to change and suddenly I found myself typing with relative ease. I’d still occasionally catch the wrong key but overall I could turn out text at an acceptable pace. I wouldn’t say the 200LX is the best device for writing, blogging or any decent jaunt of typing for that matter. As a note taker it isn’t half bad, but to be honest there are better options available, but we’ll get in to that later.
The QWERTY keypad takes up roughly a third of the physical width of the device with a numerical pad occupying the remainder. What you’re left with feels awkward and slightly squashed to use. I can’t help thinking this might have been avoided had the designers simply used a full size keyboard, assigning the number pad down the right side, accessible via an FN key, a feature that was not unheard of in the late 80s and which is still used by laptop manufacturers today.
Setting aside my issues with the keyboard, the 200LX is actually a very capable portable PC or as it was known back then, IBM compatible. Written in gold above the screen is reads “Palmtop PC-2MB RAM”, that isn’t a gimmick or HP trying to use some fancy words to make the 200LX sound better than it is. The 200LX is as much a PC as any IBM XT, running DOS 5.0 on an 80186 compatible HP Hornet CPU. You can run a variety of DOS programs ranging from early DOS versions of Microsoft Word & Wordstar, extending even to a few old CGA games. Just don’t go expecting Wolfenstein or Doom, as I honestly struggled to get much more thank Zork to work for me. Sadly the display on the 200LX doesn’t lend itself well to fast moving graphics, ultimately suffering with motion sickness inducing screen blur. That being said, it doesn’t mean you can’t have some fun with the tiny computer, just so long as you work towards the machines strengths and not its weaknesses.
It’s due to DOS support that the 200LX, as well as the 95LX and 100LX are still popular today. Should you happen to own industrial equipment such as a CNC machines that uses DOS specific software to input data. A HP Palmtop might offer a compact, inexpensive means of communicating with your machines without the need of a bulky desktop computer or laptop. In addition both the 100LX & 200LX are capable of reading from compact flash adapters through their PCMCIA ports, making it easy to transfer files to and from the device without need of the data cable.
The 200LX also comes equipped with an IR port, offering the latest in 90s wireless data transfer. By today’s standards the baud rate is lacklustre and you’ll be hard pressed to find much to interface it with. There were some compact infra red printers manufactured back in the day, which I believe will link up to the 200LX.
Overall the 200LX has some good points about it, which include
-Long Battery Life on 2xAA batteries
-Built in DOS 5.0
The 200LX comes packed with an impressive list of built-in applications;
- Appointment Book
- Application Manager
- HP Financial Calculator
- Lotus 1-2-3 release 2.4
- Memo Editor
- Pocket Quicken
- Phone Book
- World Time and Stopwatch
All of which does not include any software you can choose to load from compact flash. Aside from all the available DOS software you can run, there is also a library of HP specific titles to install. Once loaded in to the memory of the 200LX, there it will remain until such time as it is deleted or the device is reset. Access to a limitless DOS library obviously has its advantages, which makes the Palmtop such an appeal device.
Taking all that in to account you could be forgiven for overlooking some of the devices other failings. Were you looking to buy one today, the 200LX still retains a relatively high asking price as a bit of collectable retro kit, valued anywhere between £50-£140.
Personally I’d find it hard to justify paying more than £60 for one of these devices, as great as they are, there are better examples of pocket sized computing. In fact while I was writing this article I discovered they addressed my issues with the keyboard in a later model, doing pretty much what I had suggested. Other companies such as Atari, Amstrad, Psion, Sharp had devices which rivalled the HP Palmtop PC. While some were less compact than others, each took a stab at offering portable computer for users on the go. Only a few however offered you an IBM compatible computer that fit in your inside coat pocket, fewer still did it as well as HP had with the 95LX and later models.
Stay tuned for the next part of the article, when I take a look at another pocket portable, the Psion Series 3.
Keep on geeking
Not long ago I bought myself a NESpi and was telling a friend about it. She went on to ask me if there was a Sega equivalent, as her brother was an avid Sega fan growing up. Sadly I had to tell her there wasn’t but that added, that building such a console wouldn’t be that difficult, me and my big mouth. Thus I found myself with a new project on the drawing board, added to all the other projects I was tinkering with. When will I learn?
Having built the NESpi and my Picade, I knew EmulationStation could easily accommodate my needs. Not only can it emulate the MegaDrive, but the Master System, GameGear and SegaCD as well. The only real question was what platform I would use for all the grunt work. A Pi3 seemed a little overkill, true it would handle anything thrown at it, but it also hiked up the cost of the build and I was trying to keep to a budget. I might have been able to pick up a second hand Pi2b, however they seem to sell close the what they cost new. I didn’t want to go down the clone route as support isn’t as good, so that left me with one option, the Pi Zero. I’d never tried using a Zero for playing games, messing about with electronics yes, but gaming just seemed a little to demanding for BCM2835 processor. However if you read up on the Zero, for such a tiny board, you realize its actually quite powerful. Clock at 1Ghz, the CPU is approximately 40 percent faster than the same chip inside the original RaspberryPi. Tests have shown the Zero operates roughly four times faster then the original Pi. While I was never going to see Pi2 performance, it would hopefully be enough to emulate the MegaDrive. It seems a little crazy that a 1ghz 32bit processor shouldn’t be capable pf running 30 year old software, but we have to keep in mind, that the Zero is being call upon to accurately emulate a whole console. Translating sound, display, input on the fly, into something close to the real thing.
From the beginning my intention was to alter the MegaDrive very little, in fact I wanted to replicate the consoles original functions. Allowing the Power and Reset buttons to work pretty much in the same way they had before. I was able to make this possible using Pimoroni’s on/off shim, this tiny board sits atop the Pi’s GPIO header and allows you to safely shutdown the computer with the touch of a button. It also comes with through holes, allowing you to solder your own button to the board. The shim is pretty versatile, you can either use the included header block or solder the shim directly to the GPIO header, thus freeing up the GPIO pins if say you wanted to use another HAT, like a PHAT DAC. Once installed, for the shim to function you must plug power in to it directly and not in to Raspberry Pi. That way power is being fed through the shim in to the Pi via the GPIO header, putting the shim in control of feeding power to the Pi. The added bonus to all of this, is that your bypassing the Pi’s annoying poly fuses.
With the power sorted out, the next step was the Reset button. The Zero, like other Pi’s comes with a pair of through holes labeled ‘RUN’. If you short them, the Pi’s CPU will halt what it’s doing and reset the system. Ordinarily this isn’t something I would recommend doing regularly, as you run the risk of corrupting your SD card. However, if your running a Pi and for what ever reason it locks up. If your only input devices are two joypads, a reset button might just be what you need to get back on track. This was first time I’d ever wired up a reset button on the Pi and later was thankful I had, as on one or two occasions EmulationStation locked up because I’d done something stupid.
Out of the box, the Zero comes with only a single micro USB port, which isn’t much good if you want a two player game of GoldenAxe. To work around this problem, I used a compact USB hub, specifically suited for the Zero as it came with molded micro USB connector and not a full size USB plug. I then used a set of cables to extend two USB ports to the front of the console, where the joystick ports had once been. I also made a custom power lead, one end going to the rear of the console as a dedicated power socket and the other going in to the on/off shim. Always use thick gauge wire when extending the Pi’s power socket as it only take a little voltage drop for the dreaded ‘undervolts’ icon to appear in the top right hand corner of your screen.
For the rear panel of the MegaPi, I designed a custom I/O panel to replace the Megadrives existing RF and Power Jack with micro USB and HDMI. After cutting out the existing panel, I hot glued the laser cut acrylic panel in place, along with the cables coming from the Zero. I applied a copious amount of glue to both sockets, especially the HDMI port as I found it a little tight when I was hooking up my TV.
Press My Buttons
I’ve already mentioned how I was able to get functional Power and Reset, but getting both to work with the cases existing buttons was a challenge unto itself. First I began with two tall 6mm tall micro switches, which I soldered to strip board and later trimmed to fit the area under both red buttons on the case. It took a little trial and error, trimming the height of both micro switched until they worked properly with the buttons. When I had both working to my satisfaction, I used my trusty glue gun to affix them to the underside of the top lid. Glue guns are by far, the makers best friend!
With the both switches in situ, all that was left to do was connect them up to the pi itself. A quick test, proved both worked as desired and so the next task was setting up the software.
Without a doubt, building the Megapi would have been a very different story if it were not for EmulationStation. Setup and configuration of this software has been made very simple, allowing even the most inexperienced to follow it. Configuring the Sega style USB controllers I’d bought was a little fiddly but trial and error eventually prevailed and I had both working as desired. I was even able to setup a custom loading screen and Sega themed booting screen. The first time I came to try out a game, I was really surprised by the performance. The Zero handled most games I threw at it, struggling only once or twice, I doubt very much it could handle any of the 32x or SegaCD titles. But as a bog standard Megadrive it copes pretty well, better then a £5 computer really ought to. But it just goes to show what good value the Zero is and what it possible with such a cheap, tiny computer. I’m really glad the foundation developed the Zero, with the increasing speed of the larger Pi3b and now 3b+, it stands as an affordable foot in the door. Had the Zero not be around, I probably would have tried to buy a cheap second hand Pi2. For the simple fact that the Pi3 was too expensive and powerful for my needs. That being said, I’m not even certain the larger Pi form factor would fit inside the MegaDrive II case.
This was a fun project and not one I would have made had it not been for my friend asking. Truth be told, once built, I grew really attached to it and was sad when it came time to hand it over for my friend to give her brother. From what I gather though, he really loved his birthday present. Hopefully he’s reliving his childhood, maybe even having a mate over for a few beers a game of sensible soccer or Sonic and Tails.
The on/off shim is available via the Pimoroni website at
Card corruption isn’t anything new on the RPi, if your a Raspberry Pi owner it is a fair bet that you shall encounter it eventually.
Over the years ever since owning my first Pi, I had to deal with the occasional segmentation fault. But I’d never encounter a full blown SD card failure until the other day, when quite unexpectedly the PiDP8/i decided to have a system melt down. The first signs indicating something wasn’t quite right, was when I discovered my fail2ban jail log was corrupt, full of complete gobbledygook. After a reboot of the server, I discovered everything was back to normal or so it had seemed. The next indication problems lay ahead was when I noticed files I’d previously deleted had reappeared on the SD card. Now if there’s one thing Linux is good at letting the user do, it’s delete precious files without much chance of recovery. I once deleted an entire partition of my hard drive by mistake and yes, spent what was left of the night reinstalling Xebuntu. Linux is a powerful OS in the right hands but for the experienced it can be a steep learning curve of mistakes and mishaps.
After spending a full day working on my SD card, I discovered sure enough that the internal 8GB card had died a death. I read from the drive, but could neither format or re-partition it.
So what now? Well my next step is going to be getting my hands on a new SD Card, but I’m not so certain I feel comfortable using it as the primary storage on my PiDP8/i server. Everything I’ve read online indicates using SD cards for prolonged periods is not a great idea, mainly due to the limitations of the technology which doesn’t lend it self to constant read / writes. It’s worth remembering that ever since the first compact flash drive, memory cards were originally intended for cameras and PDA devices, neither of which really hammer the SD card unlike Linux. SD cards have a finite number of read / writes, from the time you plug it in, your memory card is degrading. On a short time project this isn’t a problem and there is evidence to suggest capacity does play a part, with larger cards such as 32, 64 and 128gb lasting longer then 8gb ones. Still if I want my server to be online 24/7, I’m better off finding a more reliable and permanent solution.
A hard drive is one I guess, but a little bit overkill for the tiny PiDP8/i. Which is why I’ve spent the past few days looking up ways to boot the Pi2 model b motherboard from a USB flash drive. Research suggests boot time will be faster and reliability significantly better then using SD. So in my next article I’m going to cover the process of setting up a RPi2 model B with the OS installed on USB pen. If your a Pi3 owner you have two choices, you can follow what I’m doing and it should work just fine. But unlike earlier models, the Pi3 can boot directly from USB by altering the OPT within firmware. Once enabled the Pi will search SD and USB until it finds a bootable partition.
Greetings to all you t’interweb surfers, its that time of year again and here at ByteMyVdu we like sharing the festive spirit. I say we, but really it’s me, muggins sitting at the keyboard doing everything, using the royal ‘we’ just sounds better!
Over the past 12 months I’ve built a PiDP8i, a RetroFlag NESPi, Modded a 60s radio and played about with a Sinclair QL. I’ve also built another Amiga 600Pi, refined the designed and improved on what I did the first time around and after all of that, I’ve yet to upload it to my site.
All that aside its Christmas, a time for good will and giving friends and family gifts wrapped in pretty paper. So as a thank you to the poor soul who accidently set their home page to my site, I’m releasing a spanking new set of Picade cabinet artwork. Drawing inspiration from the 80s, these templates will turn any unadorned Picade in to retro throwback. I’ve been asked a couple of times over the past year about my Picade art, so I decided to make some new never seen before templates. There’s already quite a few out there on the Pimoroni forum but a lot of them are either using copyrighted material or trying to replicate an existing arcade cabinet such as Asteroids or Bubble bobble. That’s alright, but I wanted something a little more unique to the Picade, hopefully that’s what I ended up with. Either way I hope someone out there will have fun with them, Merry Christmas you guys! 🙂
Legal fluff – These templates are offered as is and are strictly intended as freeware, for none profit purposes.
Wishing Everyone a Happy Halloween!
And of course so 8bit to get you in the mood!
The Atari Lynx arrived on our shelves 27 years ago in the winter of 1989, only two months after Nintendo released the Gameboy and a year before the Sega’s colour handheld the GameGear saw light of day. Featuring the first backlit colour screen on any portable gaming device, the Lynx boasted accelerated 3D graphics.
Developed by former Amiga designers R, J Mical and Dave Needle, the ‘Handy Game’ came about after former Amiga manager David Morse approached them about designing a portable gaming system for Epyx. In 1989 faced with financial difficulties Epyx found itself partnered with Atari Inc, who agreed to handle production of the ‘Portable Colour Entertainment System” leaving Epyx to handle software development. Between 1989 and 1995 the Lynx was reported to have sold 3 million units world wide, but ultimately failed to beat the Gameboy even though technically superior in many ways. The Lynx is a fantastic system to add to any collection with 72 games released officially, varying from run of the mill to great titles like Chip’s Challange,
Todds Adventures in SlimeWorld and California Games. However like most systems from this time its not without problems, the most predominant of which is screen failure. Usually this appears first as one or two lines running vertically or horizontally across the screen, more follow until the display is unusable. The root cause of this is the ageing ribbon cable that links the logic board to screen, over time becoming fragile and brittle. As it is an integrated part of the LCD display the only way in which you can cure the fault, is by swapping to screen for a new one. Which wasn’t a problem back when the Lynx was new, but in 2017 you might be faced with a problem, that is until now.
A Proper Solution
On AtariAge back in 2015 a user by the name of McWill came up with an interesting solution to solve the problem that had been plaguing so many Lynx owners. By developing his own custom display board he was able to replace the old failing screen with a modern LCD which not only offered superior picture quality but an optional VGA out. Unsurprisingly the board was an absolute success with Lynx owners far and wide, who finally had the means to repair their ailing consoles. Last year I was lucky enough to buy one of McWills kits, the board requires some self-assembly and a reasonable understanding of how to solder is needed. McWill does offer and installation service for those who don’t feel confident installing the kit by themselves. I was completely blown away with the image quality, which is ten times better then the original 90s LCD. The picture is sharp and the back light more linear, the full screen is now illuminated and gone is the incandescent tube glow of the original florescent light. The new screen uses modern EL technology which has come on leaps and bounds from when the Lynx was originally released. Ghosting and trailing has been significantly reduced, if not illuminated compared to the original 90s screen. If like me you’re accustomed to viewing your games on the old screen, seeing them for the first time on the new one can be a pleasant if not slightly shocking experience. I was honestly left wondering how the heck I’d managed for so many years without McWills screen mod.
Priced at around 100 Euros the kit isn’t cheap however if you figure in the fact you’re getting a custom printed PCB and LCD its actually not bad value for money. The PCB is well made and laid out easy enough for even the budding amateur to follow. However the single sheet manual could have been written a little better as I stumbled to following it wiring to the TPR solder point. The wiring for this can depend on your model of console and what I didn’t know at the time was that I needed to close a jumper on the custom PCB. Labelled in small print as JMP1 in the printed manual its easy to miss and nowhere else is it referred to by this name. For instance here is an excerpt from the instructions.
‘For LYNX-II with chipset 1 (C104129-001) you have to use TPR (testpoint 27) only. For using TPR jumper is closed, for using RES jumper is open !’
The instructions feature several diagrams with all the solder points labelled with names such as GRD, TPR, RES, CL2. I’m not entirely sure why the solder point is referred to as ‘Jumper’ and not JMP1, but it definitely threw me and I was left poking around the board until I consulted AtariAge. There I thankfully discovered I wasn’t alone and others were also being thrown by the same issue. This isn’t to say the manual is bad because it isn’t, only that it could probably benefit from a slight bit of revision to prevent others from getting stuck. Fortunately Marco aka McWill is a very helpful and friendly chap and after shooting him an email I was back on track.
Assembly will probably take you a couple of hours and I certainly advise taking your time and not trying to rush it. Some of the soldering can be fiddly, especially when it comes to attaching wires to the display pins on logic board. Using a fine tipped soldering iron is highly advisable. For wiring I used a good old trusty IDE cable, fine enough to fit on the small traces and flexible enough that i can manipulate the screen and board without working loose a connection. You will need to remove seven components from the main logical board before you can begin hooking in the new screen. You may also have carry out a 5 Volt check after removing the require components, so as to make sure the board isn’t exceeding 5.45 volt.
According the instruction the screen mod also has the ability to emulate the scan line effect of the original Lynx display, however I’ve been unable to get this to function. Not that I think I would really use it as the crisp look of the new display is pleasing enough and the games simply look amazing. If your Lynx is looking a little tired and you fancy giving it a face lift, I highly recommend getting one of McWill’s kits. While admittedly pricey, it will likely out live the life of the Lynx itself and beats replacing one old screen for another. As it’s only a matter of time before the ribbon cable degrades and your left looking for yet a replacement from a donor system.
Until next time, keep on geeking!
For a long time I’d thought about creating a portable Pi but wasn’t really certain where to begin, so for a long time it remained just an idea rolling around in my head. After building the 600Pi I developed a greater understanding of what was involved fitting a Raspberry Pi inside a custom enclosure, such as extending the USB, HDMI and Ethernet from the tiny Pi and how to power the motherboard directly, bypassing the traditional on board USB port. The 600Pi really opened my eyes and taught me a great deal, not just about wiring, but also about hacking the Pi’s various features. A month or so after finishing that project a friend gifted me a box full of random bits, because if there’s one thing friends know about me, it’s that I love boxes filled with parts. Inside was an assortment of USB cables, fans and a RPI2 B fitted in a custom acrylic case. What caught my attention about the Pi specifically was the 3.5″ LCD panel that was attached to it, as soon I saw the screen the cogs in my head begun to whirr. Well suited for a portable pi project, it was just a matter of me drafting up a design.
A few weeks after receiving my box of goodies I was clearing out a bunch of old stuff from under the bed when I found an old project box lurking under the mattress. A left over from when I was designing my Nomad desktop system, it was just the right size for a portable retro computer, not to mention it already looked kind of old. Originally there had been two but I’d hacked one up for the Nomad, only to find it had very little air flow and caused the mini ITX board to overheat. However, unlike the larger mini ITX board, the Pi not only had a smaller foot print but would never reach the operating temperatures of an Intel Duo processor. At first I wasn’t certain the LCD panel would fit in the front of the case, but pairing the two together proved it would be a snug fit.
Admittedly, building a portable Pi isn’t anything new, people have been putting them inside all manner of things ranging from teddy bears, tea pots, remote control drones and even coat pockets! You can find Pi powered laptops, C64s, Spectrums and even 3D printed Gameboys like the Pi-GIRRL, however my goal was to build a portable computer with a distinctive 80s retro feel, bet you didn’t see that coming did ya! Using a case originally intended for my Nomad desktop, I decided to call my new portable the ‘Nomad SX/Pi’ in homage to my earlier project and also the Commodore 64SX portable computer, a machine I was drawing much inspiration from.
It’s probably no surprise the SX64, Keypro, Osborne and even the TRS80 M100 inspired the design of my project. All are note worthy machines, successful back in their day with a dedicated group of followers even now. Their appearance resonates a specific time in computer history and it was this aesthetic styling that I wanted the Nomad SX to imitate. Measuring 257 x 190 x 85mm the case had ample space for the Raspberry Pi, however the 3.5″ LCD was another matter. It was almost as tall as the case with only 10mm clearance between the top and bottom lid. As I had done with the 600Pi before, I extended the Pi’s ports to the front and rear panels of the case. Included in the rear panel was:
- 1 x USB
- 1 x RS232
- 1 x Ethernet Port (Rj45)
- 1 x MiniUSB (Power Input)
For the front I extended the Pi’s audio jack and another of the USB ports along with the Pi’s power and activity lights. Having only recently upgraded the 600Pi with a new Pi3, it meant I had spare Pi2 board with the on board LEDs already modded for extending to the front panel. The reason I didn’t extend all the USB ports was because I needed two of them for Bluetooth and Wifi.
After making a couple of rough sketches I sat down, using Inkscape to draw up the vectors I would need to cut the front and rear panels out of acrylic. Previously I’d used an old version of Adobe illustrator, but a couple of my friends kept insisting I gave Inkscape another shot, even though I’d struggled with it the first time round. My initial impression of Inkscape was that it was powerful but far less intuitive then Illustrator,, but it does have one thing working in its favour. Unlike Illustrator its an open source freeware application, meaning it doesn’t cost you a penny to use.
Installing it on the Nomad, I spent the evening drawing the panels using the sketches I’d made earlier. After a some what slow start, I actually found Inkscape to be pretty straight forward and not as complicated as first thought. In fact once your in the Inkscape zone it’s actually a pretty powerful application. Available for Linux, Mac OS and Windows, I highly recommend checking it out and did I mention its available for the Raspberry Pi?
Input / Output
One part of the case that was causing me a headache was the keyboard, originally I’d wondered if I couldn’t buy a small keyboard and hinge it to the front of the case similar to the Keypro or attach it with Velcro. However that meant finding a keyboard with the exact same dimensions as the front panel which was highly unlikely. Unlike large manufacturers that can fabricate custom parts, I was limited to finding off the shelf parts to get the job done. After a lot of searching on eBay, I found a wireless keyboard and waited patiently for it to arrive from China. Almost as soon as I unboxed, I realised it was rubbish,
surprise, surprise. The touch sensitive panel was smaller then I’d expected and pretty useless for typing anything. That is unless you wanted to finger type everything, which as I found resulted in almost inebriated sentences of typo ridden nonsense. So it was back to the drawing board and searching once more online for a suitable keyboard, a search that had thus far been less than successful. It turned out I hadn’t needed to worry as only a couple of days after my disappointing eBay purchase, my prayers were answered. While picking the other half up from work, I was telling her about the problems I’d been having when suddenly she revealed her work stocked several bluetooth keyboards on their online shop. A quick trip across
the warehouse floor and I was staring face to face with an ultra slim bluetooth keyboard and not just that, it was narrow! Talk about irony, I’d spent the best part of a month looking for one under 250mm wide and all the while Pimoroni had exactly what I’d wanted on their website and it was 240mm wide, 10mm shorter then the case I was using.
With the issue of the keyboard finally behind me I was able to redesign the front and rear panels to accommodate the new BT keyboard. Originally I’d planned for the little touch panel keyboard to slide inside a slot in the front, but as that wasn’t happening now, I had to find room to accommodate the larger 240mm x 90x 14.5mm keyboard. Barely 10mm narrower then the case, I had to come up with a smart way of stowing it away. Strapping it to the outside would undoubtedly expose it to unwanted knocks which would likely wear it out in no time at all. Don’t ask where the idea came from but scribbling on a piece of paper I found myself staring at a sketch of the rear panel with a narrow slot for inserting the keyboard inside. Refining the design further resulted with a shelf inside the portable for the keyboard to rest on when it wasn’t in use, I also designed a blanking plate to screwed in place over the slot to keep the keyboard from sliding out while the computer was being transported. While it wasn’t like anything I’d seen on the Z80 portables I’d been using for reference, it certainly worked and solved the problem of where to put the keyboard.
As there was no need for a slot in the front panel I redesigned it, turning it in to a sliding door and IO plate for the audio jack and USB port. Taking advantage of the reclaimed space I also included a badge to sit above the IO panel which read “Nomad Pi/SX – Portable Micro Computer”. It seemed fitting given the size of the Raspberry Pi computer hiding inside the case.
Setting up an Ultra Slim keyboard on the RPi wasn’t as smooth sailing as I’d been expecting and required some work before it was up and running properly. I also encountered an annoying problem where the top row of F keys weren’t recognised by Linux, even asking the guys at Pimoroni and on the RPi forum yielded no solution. Two months after finishing the portable Pi I was at a friends sampling a pint of homebrew beer when the answer came to me. I don’t completely recall what led to the discovery (how strong was that beer?), but long story short Linux was mistaking the ultra slim keyboard for a BT Apple keyboard. It turns out these are known for having issues with Linux and there’s even a wiki page covering it, see this link for details.
For the Pi’s composite video jack I used a 3.5mm jack cable, splitting the left, right and video lines. I hooked the video feed up to the LCD panel and the audio channels to the audio socket attached to the front panel. At some point I plan on installing internal sound but that will be a work in progress. When I discovered the PI / LCD combo, I originally wrote down the wiring so that I’d know how to connect it back up. Like any scrap of paper it inevitably went missing and not knowing the model of the screen or where my friend had bought it, I was left in a bit of a pickle. How was I ever going to figure out the wiring? Luckily for me I’m on the Sheffield Hackerspace mailing list and after posting up a request for help, I soon had a link providing me with all the info I needed to connect up my tiny screen. Words honestly can’t do justice for how grateful I was when the tiny LCD lit up for the first time, so a big thank you to the guys at the Sheffield Hackerspace.
Because I was planning primarily to use the terminal and not x.org to operate the Pi, I found the text on a 3.5″ screen a little difficult to read. Online I found several guides showing ways to increase the text size within the Linux console, and I also read up on altering the screen resolution which was running in its default res of 1080p (I guess). Either way it was causing the 3.5″ screen to flicker at a headache inducing rate. Fortunately the config.txt is pretty flexible and allows you to tailor a lot of the Pi’s settings to suit your needs, which is great for anyone trying to use a 3.5″ screen with their Pi via composite out.
Tackling Small Screens
Having only ever hooked a Raspberry Pi up to a VGA monitor, I’d little experience configuring the config.txt file to display on a small screen. Especially one using composite output instead of HDMI. Fortunately there’s plenty of information available online to walk you through setting up the config file and a bit of trial and error I was able to get it working. By setting the screen to 480×320, I was able to eliminate almost all of the screen flicker present while the screen was running in high resolution. Additonally making it much easier to read text, as even in 800×600 it was incredibly small. Though lowering the resolution made the text more legible it still wasn’t suitable for using over an extended period. This led me to looking at changing the Terminal itself and how I could configure it to display differently on the Pi Portable. Fortunately you can alter the Terminal using the following command
"sudo dpkg-recofigure console-setup"
Going through the prompts I set the terminal to use the ‘TerminusBold’ font at a size of 11×22 as this was easy to read and didn’t take up to much room on the screen. It took me a while to figure all this out and I went through several computations of the various fonts and sizes before I found the right one. While doing a little research for this article I discovered one of the machines I’d used for inspiration has a larger screen than I’d first assumed. The Osborne-1 is often cited as the first portable personal computer and it along with the SX64 were machines I used as examples while designing the Nomad SX. As it turns out the 1981 Osborne-1 came with a 5″ screen capable of a mind blowing 128×32 character display. Which is impressive compared to the 11×22 display on the Nomad, if I ever make another portable I’ll be sure to make the screen bigger!
Not A Leg To Stand On
After getting the machine together I realised the viewing angle wasn’t exactly ideal. In fact to read the screen I had to prop a book under the case. I’d not really envisioned using a stand like the SX64, but as it transpired I actually really needed one. If I’d stopped to think back about all those old Z80 machines, a large number of them did come with a kickstand of some sort. Designing a set of legs I got them laser cut from acrylic and fitted to the sides of the case. I used nylon lock nuts so that I could tighten the screw enough so the legs were stiff to move, but with the advantage that lock nuts wouldn’t work themselves loose. The downside to using acrylic is that under certain circumstances it can be a fragile material and exposed to stress will sometimes shatter or crack. As the legs would be in regular use, I wasn’t certain how long the acrylic would last. With that knowledge ever present in my mind, I spent a lot of time trying to think of an alternate solution. Eventually I settled upon 3D printing and fabricating a single piece carry handle, as you can see in the picture the prototype came out pretty good.
Part of this project was to make a portable micro computer that I could take with me wherever I liked. This ultimately meant using a battery, something I’d never done with a Pi before. So once I had the system working and all of the internal wiring finished, I began looking at batteries and also charging circuits. Obviously because of the screen, bluetooth & wifi dongles, I would need a pretty substantial battery to power everything. It was around this time that Pimoroni began stocking batteries via their online store. I also noticed they stocked the Adafruit Powerboost 1000C, a small 5v 1Amp board that doubled as a battery charger. Choosing one of their 4400mAh batteries and the power boost, I set about modifying the internal wiring of the Pi Portable. Instead of the power going directly to the Pi it would have to go via the Powerboost first, so that the internal battery could be charged.
I’ve seldom bought anything from Adafruit aside from perhaps a micro usb socket but I have to say the Powerboost is a fantastic bit of kit and really does credit to Adafruit. Not only was it straight forward and simple to wire up but I found the additional
power switch an especially nice feature, one that I hadn’t been aware of at the time of purchasing. It was certainly a lot better than pulling the plug, as is the normal way to turn off your Pi after shutting it down. As the back panel was in need of revision due to some stress cracks showing, I added an additional hole for a switch, which complimented the rear panel really well, giving it a very professional look. Combined with all the accessories, the Pi portable draws approximately 740Mah, which means I should get nearly 5 hours out of the 4400 battery. I’ve yet to actually bench test the Pi portable to find out if those figures are anywhere near accurate, but even if the system can manage 2 hours, I will be happy and consider the upgrade a success.
While it might not be as sleek or as compact as many other portable Raspberry Pi builds. I’ve taken the Nomad Pi/sx to several retro events and had nothing but positive feedback. Many remember using machines like the SX64 and Osborne back in the day and instantly latch on to the similarities. Loading up Dizzy via the C64 emulator never fails to generate a smile. But if I’m honest, I always end up playing Outrun or Stuntcar racer!
This has been a funny old build but one I’ll definitely remember if not for the fact that I do use the computer on and off when I need a distraction free typing environment.