I am very sensitive to electromagnetic and radiofrequency radiation and most electronic/"computerey" devices stress my nerves out, tend to make me angry/combative and leave me unreasonably tired all the time, and for this reason I sadly can't really use computers and the like on a long-term/consistent basis (despite my interest in and aptitude for technology in general) if I want to avoid these issues, which are irritatingly consistent in their occurance.
This has been a big problem for me for some time particularly with regard to communication: I've frequently needed to be able to communicate ad-hoc with my family when they and/or I need to split up for whatever reason, but because of my sensitivity, even a basic cell phone would not work for me long-term to the fact that the cellular radio network is by design "always on" and thus always transceiving (see very end of post for more details). This issue has had me scratching my head for a few years now, a little while ago I came up with a possible solution.
About a year ago I found an Ericsson Mobile Companion PDA-type device in an op-shop, and grabbed it thinking I might find it of historical interest at some future point in time when I might be "fixed", fully expecting it to tire me out (or worse) if I tinkered with it. Happily, though, as I tentatively then more confidently used it for longer and longer, I was surprised to find I suffered no ill effects as a result of using it. (Note that the device incorporates a web browser and email program, but actual radio connectivity was originally accomplished via an IrDA connection to a compatible cell phone.)
As one of the first "computerey" devices I think I can actually use on a consistent basis without problems and which does not seem to fatigue my nervous system, which is abnormally sensitive to practically everything electronic for some as yet unfortunately unknown reason, this PDA has opened up a world of possibility to me. It may not surprise you to hear that I actually typed this post on it... but I had to transfer it to a PC via a CompactFlash card in order to actually post it. Wi-Fi connectivity, which I know from experience I am okay with for very short intervals, would be a real boon to have: I not only wouldn't need a full computer to be able to browse the Web, but most importantly, I'd be able to employ the growing myriad of free Wi-Fi hotspots in urban centres to connect to some kind of chat or communication system. This idea might sound like something insignificant in this day and age, but it would be revolutionary for me.
Sadly, however, I have one major concern about my MC218 which leaves me very reluctant to try and get Wi-Fi working on it (although I *probably* could find a way, thanks to the fact that it seems to run Linux (2.4) reasonably well): durability. This PDA is almost freakishly delicate. I read shortly after finding it that the LCD ribbon cable on the Psion Series 5 (which the MC218 is a licened clone of) - which is is flexed every open/close cycle - has an artifiially limited lifespan due to a silly manufacturing design decision, and since I've no idea if I'm susceptible I try to leave the lid/screen open whenever I can, and I am particularly careful with the device in general, but despite these efforts - and the fact that this device was actually in practically as-new condition when I found it - over the few months I've had it, the case, which is made of very solid-looking but thin, brittle plastic, has cracked in about 5 or so places, the most disasterous being the entire screen-hinge-foldback mechanism (which I managed to fix with thin wire hidden inside the chassis, so thankfully I can still close the lid perfectly if I need to), and the DC power input socket (thankfully it has one!) has recently started to play up as well (I think it's at the beginning stages of coming unsoldered
). I guess this is to be expected of a 13 year old device though. :P
So with fixes in tow, this PDA is still puttering along, but I'm on a (slightly urgent!) quest to find PDA 2.0, something as electronically identical as possible to my current device but with a slightly tougher, more rugged design and which I can *somehow
* cram Wi-Fi connectivity into, if it's not already on board. Additionally, it needs to be self-contained enough that I don't need a computer (or a perpetual Wi-Fi connection to one - I did say "short intervals" before, meaning a few minutes or so) to maintain the device and (of paramount importance!) write apps for it like I can with the BASIC-like OPL programming environment on my current PDA (which is IMHO its awesomest feature and star attraction). Ideally this would be an on-device C compiler....I can hope (and I really do).
I've done some digging to see what's out there that might fit, but Google isn't particularly good at abstract/horizontal/categorical searches like "find really slow devices that have had Linux - or something just as relevant and flexible - hacked onto them regardless of what OS they officially run" (or shortened search phraseology thereof), and so far I have been presented with PDAs and gadgets which are ~70MHz but only run Linux 2.3 and are highly likely incapable of having Wi-Fi added
; run Linux 2.6 and are freakishly obsessed with 300MHz+ CPUs
(meep), color screens (meh) and some form of accelerated graphics processing (nooooo); or which are 75MHz, run Linux 2.4 and incorporate Wi-Fi but only work (driver-wise) with a commercial Linux environment
(ack!) and which would be particularly fruity to hack a touchscreen and battery onto. *Give up* *Formulate post* *Locate likely-looking forums* *Submit* :P
I've also found that most of the things I've seen which I did consider for a moment or two often don't seem exist anymore or are inaccessible to buy today. Thus, I'm particularly interested to hear from people who remember and/or have experience with specific, obscure/unorthodox/out-of-the-way, not-so-simple-to-find devices which might work out for my requirements. In other words, I want to hack something together. :P
So... my current PDA's specs, and PDA 2.0's requirements:
- CPU: this MC218 is powered by a 36.864MHz - yes, I just said 36MHz - ARM710T (arm4vl class) CPU, and my next PDA cannot be much faster than that - I'm thinking 60MHz, tops. Yeeah. :P
- RAM: I currently have 16MB of RAM to play with which continually dukes it out with an interna OS-juggled RAMdisk. I'd like 32MB at least for my next device, and ideally 48MB+ which would let me start thinking about basic on-device C compilation, but I draw the line at 8MB-16MB.
- Storage: Despite the fact that it would have probably cost $80,000 at the time, this PDA actually works absolutely fine with the 2GB CompactFlash card I tentatively bought for it (!). Thus, I'm currently comfortable (well, sorta) with 2GB of storage, but at the very least I need 256-512MB for user data (ie, not counting OS storage requirements), considering I can probably store/archive/access most everything else I'll need using Wi-Fi.
- LCD: I currently have a backlit, touchscreen, monochrome LCD to poke at and play with, which the ARM710T directly drives, GPUlessly, in either 4- (typically) or (at most) 16-greyscale mode. I would very much like a backlight in PDA 2.0, and I am neutral on whether it is monochrome or color, but... (see next)
- GPU: The device cannot have a GPU in it, since I've found myself to be particularly sensitive to these on multiple occasions. No exceptions.
- RTC: An onboard RTC is vital so the device can (with the obvious exception of the RTC) sit completely in standby/sleep mode - the only state in which I'll accept having it in my pocket long-term - and periodically wake up every 20-45 minutes to check for new messages. My current PDA also has "instant-on": both Symbian EPOC 1.05 (its native OS) and Linux "wake up" when I press the On key to whatever I was looking at when I put the device to sleep, and this would be a nice (and very practical) finishing touch to RTC wakeup, and make the message-check process much quicker too.
- Keyboard: I love the keyboard on my current MC218, despite the fact that to type this sentence correctly I had to press Backspace approximately 12 times. I think a keyboard would be nice, particularly since PDA 2.0 will justify its place in the budget as a communication facilitator, but a physical keyboard is... not *totally* essential :/ (But it will of course need a touchscreen if it has no keyboard!)
- Wi-Fi: 802.11a APs are already few and far between, and -b and -g will eventually disappear as well as more and more 802.11n- and -ac-only units come online. Ideally I want to be compatible with everything - especially -ac since I then won't have to worry about upgrading for years, if it should come to that - but I draw the line at at least b and g, and preferably b, g and n.
- Alerts/notifications: Some kind of audial and/or vibrating alert mechanism is *slightly* neccessary so I know when new messages come in (!), but it doesn't have to be fancy: a single-tone beeper would suffice at the very (funky) minimum, although something capable of (even basic) PCM playback would definitely be a plus.
- Battery (life): If I hadn't built a little (linear - no SMPS for me!) 6V PSU for this PDA, I'd have gone insane eons ago with how it chews through a standard pair of AA batteries in around ~20 hours (I use it continually continually xD). Rechargeable battery(s) would be very nice, but aren't totally necessary.
See my problem? :P
This is by far one of the trickiest, most difficult questions I've ever asked on/of a forum, and while I have absolutely nooo idea what you'll all come up with, I'm open-minded, and am certainly looking forward to your responses and ideas.
I'm not beyond building this device myself, but it does still need to be able to fit in my pocket
Due to the fact that I don't have this device right now I won't be able to check this thread particularly frequently (catch 22!), although I will try to poke my head in at most a week or so from now.
for anyone who might raise the issue of cellular radiation vs. Wi-Fi radiation:
From an RF testing perspective, AFAIK most tests measure Wi-Fi radiation at a few meters, and cell radiation (from the tower
, not the phone!) quite a bit further away, so of course the cellular radiation levels in such tests always measure lower. Just what I've heard.
At the end of the day, a cellular solution would *probably* actually work out okay from a RF sensitivity perspective, since the RF bursts would be intermittent and very short (a few seconds every 30-45min. or so).
My real problem is this: the average "basic" cell phone is built such that that the cell radio and its associated microcontroller(s) can notify the phone's main CPU of incoming calls at any time, and also so that keypad actions will wake the screen up instantly. As such, it would be completely irrelevant for a phone CPU to go to "sleep" in the way I've talked about in this post, so no phone firmware would incorporate the capability. Also note that the CPU in a basic cell phone is I think nearly 100MHz. Furthermore, only the newest, fanciest 400MHz+ CPUs provide the "oomph" neccessary for sufficient on-device functionality to justify a software cell-module off-switch. Thus, the only type of cellular solution I'd be able to use - one I could completely switch off - would likely be some kind of geometrically overgrown slow-as-molasses serial-to-cellular GPRS modem module type thing, and this would very much be a last resort because it would not only be so insanely slow (Wi-Fi is very attractive in this regard! ~54Mbps+ vs. ~25kbps? Ha!), in this 4G-obssessed day and age it would be nigh impossible to find a cost-effective data plan for it - I'm aware that telcos offer obscure yearly-prepaid plans for miniscule amounts of data or SMS transfer, but I'd also want to use the wireless link for occasional web browsing and data synchronization, which would not only crawl with GPRS, but it would boot me out of the "minimal data transfer" category, my only recourse being to pay for a 3G SIM card with a data cap I'd never be technologically capable of fulfilling (a lot of mobile plans specify "no continuous downloading", which would be my first requirement if I were to try and fill out a 100MB limit at 20kbps). In other words: circumstancially speaking, it would never work out. :P And Wi-Fi is freee