@Retrochallenge – So Near So Pi


I have been on the hunt for a suitable battery pack for the Raspberry Pi, there are a number of options not least of which is simply combining some standard off the shelf AA cells with a DC – DC step up converter.  I’ve ordered one such converter but I’m not sure it will arrive before the end of the month.

Epson PX-4+

Epson PX-4+

It then occurred to me that some weeks ago I bought a battery pack for my wife to enable her to charge her iPhone during an impending hospital stay.

It’s a pretty meaty pack of cells with 4 built-in USB ports, one of which claims to be able to knock out 5V at 2.1 mAh.

The Pi booted happily from this pack and ran for at least three hours however the pack is pretty bulky.

My utterly pointless goal has been to achieve some mobile, modern activities such as blogging and Tweeting with one of the machines from my retro collection.

Fitting The Pi

Fitting The Pi

Trawling through those machines that run reliably from battery I came across the Epson PX-4 which happily runs for many hours on 4 AA cells.  The Epson runs CP/M, has built-in terminal software and a considerably more legible screen than its more glamorous big brother, the PX-8.

Not only that but it’s also a modular system featuring an option bay that supports interchangeable cartridges such as a cassette player, modem, additional ROM sockets and so on.

I have a couple of PX-4s, a standard model with an external RAM disk and a PX-4+ which contains the RAM disk within the machine.  I also have a couple of blank cartridges and somewhat fortuitously the Raspberry Pi fits inside… well almost.

Low Profile Micro-SD

Low Profile Micro-SD

A standard SD card juts out too far, however by using a low profile SD to Micro SD converter the Pi fits snugly within the case.  Tantalisingly the cartridge port on the PX-4 outputs 5V, it was a bit of a long shot but I quickly hacked together a power cable between the two computers.

On powering up the PX4+ the Pi burst in to life and displayed the familiar colour screen before, well, failing to boot and going in to a loop of failed attempts.  With a meter on the cable I could see that the voltage was dropping below the threshold required when the Pi attempted access of the SD card.

    Epson PX-4+ & Pi

Epson PX-4+ & Pi

I was using rechargeable AA cells in the Epson so swapped these out for fresh alkalines giving a moderate boost in voltage.  This got the Pi a lit bit further along the boot process proceeding to the NYET/NACK/ACK error loop, a known symptom of insufficient power.  However still no go.

Unlikely as it was that the Epson could have powered the Pi straight off the bat it would have been pretty cool.  There may be space within the cartridge for an additional battery pack.  I shall be looking into that over the last few days of the challenge.

There is one other very tantalising prospect that is well beyond the scope of my abilities not to mention the time left for this challenge and that is that the cartridge port could deal with the serial communications.

Power From The PX-4+

Power From The PX-4+

However as things stand, even if my battery plan is successful, there will still be a cable running externally from the Pi’s USB ports to the PX-4’s RS232 port.

The idea of rolling up at Starbucks with a self-contained PX-4 and firing off a few tweets would be somewhat spoilt by the presence of 3 metres of cable rolled up on the table.

@Retrochallenge – Blog To The Future – Part II

Psion MC 400

Yesterday I added a tiny USB WiFi adapter to my Raspberry Pi and hooked it all up via the serial port to my Psion MC 400.  I’m mindful of the fact that a fair portion of my ‘Retro’ challenge has involved me setting up the Pi but nevertheless that’s the course I have chosen.

Adding the WiFi adapter has dispensed with one cable, I’m now on the hunt for a decent battery pack that will successfully power the Pi and allow me to loose yet another cable.  It also occurred to me that the combination of a battery pack and 3G dongle would allow some truly mobile retro fun/nonsense.


Psion MC 400 & Raspberry Pi

Using the excellent If This Then That (IFTTT) service I created some e-mail triggers that would allow me to blog and Tweet via e-mail.  I also have an account set up with TweetyMail which automatically forwards any tweets mentioning @retrochallenge to my e-mail account.

The Psion has excellent built-in terminal software and I had no difficulties connecting up to TCPser and ‘dialling’ in to my BBS.  Once logged-in I was able to check all the latest @retrochallenge Tweets received by e-mail.


WiFi Adapter Added

I then wrote a quick blog entry and posted it to this blog via e-mail.  Having done that I realised I’d forgotten to include @retrochallenge in the post title so I logged back in and also fired off a Tweet via e-mail, just for good measure.

So checking Twitter, blogging and tweeting with the Psion MC 400, utterly pointless, but strangely satisfying.  I filmed the exercise for those with patience.  A couple of excuses, filming the Psion screen is quite a challenge so in order to avoid strange reflections, moire and other problems it’s all at rather an odd angle.  And yes, one day I’ll remember to wipe the dust off of the screen first!

At around 50 seconds in the eagle-eyed amongst you may spot the @retrochallenge tweets and names such as Urbancamo and Twylo.

Blog To The Future

This blog entry is being written on my Psion MC400 connected to the Internet
via my Raspberry Pi. I have connected to my BBS and am sending the text via
e-mail to trigger the posting of the entry via IFTTT. I’ll amend the post
later with more details and some video.