OBD-II PDA Solutions

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or my current OBD-II Scanner solution, I’m making use of the Palm Universal Connector and this means that there are five PalmOS 4×x handhelds that I can use with the unit - the m125, m130, m500, m505 and m515. Whilst all of these devices are broadly similar in terms of core hardware specification - their differences are in their screens, battery and (for the m515 only) memory - they all offer a slightly different tilt to the unit. Unfortunately, there is no one PDA that can encompass the whole spectrum of possible usage conditions.

The m125

For OBD-II duties, the m125 would make a fine unit for fault code reading but could perhaps be somewhat compromised for showing live data. The rationale behind this is because the unit uses replaceable AAA batteries. When running on high powered NiMH rechargeable batteries, in theory the m125 should provide me with approximately ten hours of uptime, but these batteries require fourteen hours of charging time. When running on alkaline batteries, the unit’s uptime should be doubled. Palm’s m1xx series of PDAs has a history of backup capacitor problems, in other words, when one replaces the batteries, the PDA’s memory is wiped.

The screen is easy enough to use during the day, especially in good lighting conditions, although at night the viability of the reversing backlight remains to be seen. In dim lighting, the m125 is very difficult to use.

The m130

The m130 has two advantages over the m125. One is the rechargeable battery, although in some respects this is also a disadvantage too. Device uptime is respectable (although the older Palm IIIc shows the m130 the way home), but more importantly the m130’s Lithium Ion Polymer battery charges in around one hour. The second advantage is also the screen, which is excellent to use in dim lighting, precisely where the m125 struggles.

Unfortunately, the m130’s disadvantages are associated with the strengths. The screen is difficult to use in bright ambient conditions (the opposite of the m125), and the battery uptime is not quite adequate for a full day on the road (although to be fair, the quick recharge time does much to resolve this issue).

The m500

The Palm m500 features an almost identical technical specification compared to the m125, except is uses a larger monochrome screen in conjunction with an internal rechargeable Lithium Ion Polmer battery. Device uptime is impressive, even with the backlight in use (it should see eleven hours use with the backlight turned on), and the unit recharges very quickly. The m500’s disadvantage, like the m125, is apparent in dim lighting, rather than when dark - and it is difficult to use.

The m505

Palm’s m505 was their first super-compact colour PDA. Battery performance is adequate if not inspiring, but the screen is rather difficult to use under certain lighting. Otherwise, the rest of the hardware stacks up nicely.

The m515

The Palm m515 addresses most of the weaknesses of the m505, wrapped up in the same case but with twice the memory. It is my favourite PDA, and it’s screen is useful enough to use without the backlight during the day. Unfortunately, at night the backlight produces a strong reflection in the windscreen, thus rendering the device very difficult to use with some form of funky shield over the top, which looks ghastly in my opinion.

Non-Universal Connecter Devices

The above devices all use Palm’s Universal Connection. However, there may be an alternative - it’s not difficult to track down a serial cable for other PalmOS handhelds and this in turn means that I would be able to use my other units.

The Palm IIIxe

For the most part, the Palm IIIxe offers very similar abilities compared to the m125 with a few notable exceptions. One is that the IIIxe has a larger screen than the m125, which is advantageous for in-Ka data reading. It is also probably a disadvantage when using the backlight, since I would envisage the IIIxe’s backlight to use more power than the m125.

One other potential disadvantage is that the IIIxe’s processor is of an older, slower variety - it uses a 16 MHz version of the Dragonball EZ processor. The m125, in common with the m130, m515 and Handspring Visor Professional uses a 33 MHz version of the Dragonball VZ processor. A slower processor may mean that the device is unable to display OBD-II data as quickly, although when optimised and clocked at 16 MHz, the IIIxe is almost as quick as the m125 when benchmarking the device. Of course, if using a slower processor is no disadvantage in terms of displaying information, it will be an advantage in terms of battery life.

Indeed, with regard to battery life, the IIIxe has a claimed 25% advantage compared to the m125 for battery longevity.

In all other respects other than size, the IIIxe’s screen is technically inferior to that of the m125, but for almost all users the difference is not significant. The screen is easy enough to use during the day, especially in good lighting conditions, although at night the viability of the reversing backlight remains to be seen. In dim lighting, the IIIxe is very difficult to use.

The Palm IIIc

As the IIIxe is one of the m125’s ancestors, so the IIIc is the predecessor of the Palm m130 and its abilities are broadly similar. Again, like comparing the IIIxe with the m125, we find that the IIIc and m130 share some of the same advantages and disadvantages. The IIIc’s battery life is certainly superior to the tune of approximately 40% (although of course this is subject to use), but it uses both a slower processor and the screen update is somewhat tardy. This may be an advantage or disadvantage, depending on how well the OBD-II software works on the device.

The Handspring Visor Professional

In many respects, the Visor Professional is ideally suited to OBD-II Scanner duties. The unit uses a monochrome screen in conjunction with an internal Lithium Ion Polymer battery, a 33 MHz processor and plenty of internal memory should I wish to log data. The disadvantage is that getting hold of the relevant cabling is not so straightforward.

The Visor Professional’s screen is arguably superior to the IIIxe when showing moving data, but to all intents and purposes one may substitute “Visor Pro” for “IIIxe” when comparing the IIIxe with the m125.