Saturday, 28 August 2010

No joy with the XDA

I spent a bit of time working on the XDA without success. I sorted out a serial connection and used Bluetooth to transfer some test programs to the 'phone, but trying to access COM 1 just gets an error as if the port doesn't exist. I tried all the ports from 0 to 15 with a simple serial reader and got nothing. Checking the wiring to the board all seems well, but it is always hard to tell for sure. I'll give it one last check before giving up.

I got some technical stuff about the iPaq online and have details of how to dismantle it safely and will see if the screen flicker is maybe just a loose connection.

Wednesday, 18 August 2010

XDA Lives (ish)

On the bench with 2 power wires now soldered to the pads on the main board. This was quite easy using a magnifier because there were 3 pads for +VE and 3 for GND side by side so three times the area to solder to.Here's the XDA charging from the power supply and the power light turned yellow as well. It remains red with no battery, so I'm guessing you need a battery installed to make this thing work.Finally, here's a low shot to show the poor XDA is half naked, in fact it's backless and its guts were hanging out. Only the weight of the unit was keeping the battery in contact with the main board.

I managed to solder one of the RS232 wires on after this, but not the other one, it is very fiddly. I'll have a go tonight or tomorrow again and report back what happens.

Tuesday, 17 August 2010

XDA 2 Connector

Another kind donation, this time of a nice O2 XDA 2 PDA/Smartphone (HTC Himalaya), running Windows Mobile 2003. The owner told me the 'phone wasn't working and the battery wouldn't charge, but it was quickly apparent that the fiddly little connector at the base of the 'phone wasn't right. The cradle had an option to charge a second battery in the cradle itself, so I took the battery out of the 'phone and charged it that way and the unit powered up perfectly and did its thing.

A quick search revealed the excellent XDA Developers website with a huge wiki and a forum and I quickly had an HTC service manual for the 'phone and the pin out for the connector. I was thinking of fashioning a serial cable in the same way I did for the iPaq using the power plug adaptor (the iPaq and XDA use the same plug, but different pin out), but the power adaptor was damaged as well making me think the 'phone had suffered an accident in the connector department (always painful).

I carefully dismantled the XDA last night and was amazed when the 22-pin connector fell out of the 'phone. It must have suffered a serious shock because all of the 22 little surface mount solder joints had failed which explained why it wasn't charging! Anyway there was no mission of re-connecting the socket and to be honest that wouldn't have helped, what I really need is a power connector and a 9-pin D male for RS232, directly connected to the XDA, a little ignorant looking maybe, but for a dashboard mini computer costing nothing perfectly acceptable.

The big problem now is whether I can solder half-a-dozen tiny wires onto even tinier PCB pads, something I doubt, but am willing to give it a shot. I may try and locate better connection points further back on the main board, but everything is absolutely minuscule on these things nowadays. Bring back the Russian radio sets of the 1970s with their hand-wired transistors and cardboard cases, much easier to repair!

Sunday, 15 August 2010

Pimp my...what??

This was an impulse buy! I got this 'boom box' for £20 in B&M Bargains in Larne. The sound quality isn't bad (the speakers claim to be rated to 300W), but I'm not too sure where I'm going to fit them. Even better was when I found out you can hook up a 12 volt feed and they light up with a dazzling display of blue LEDs! Anything is better than the tinny rear speakers behind your head in the MR2, they start buzzing the minute anything lower than a contralto dares to be played through them, so a way will be found to shoehorn these in somehow.

Tuesday, 10 August 2010

C Spot Run (under DOS)

Well I have temporarily shelved the Psion II while I go back to looking at the gutted laptops for a more colourful display. I'm working on Borland C++ under DOS (no sniggering at the back, this is serious) with a full (wait for it) 16 colours, but that's all I need. There are good reasons for this, the main one being simplicity. The laptops are all Pentium I or late 486 so they need simple software and it will be keypad controlled so no need for a complex GUI. All I need is something that will read my data stream from RS232 and display it with some storage and analysis.

And here we have the first attempt, RPM and throttle position (TPS) on screen. Okay I'm cheating a bit because the data is coming from the bench test rig, but it's a step forward.

I've also had this displayed on the 7 inch LCD screen via the VGA-to-Video box, but at 640 x 480 resolution it is hard to read. I think experimenting with the colour scheme might help, but using composite video is unfortunately always going to be fuzzy. The physical rig looks good though and I'm thinking of spraying the LCD case matt black and incorporating the keypad into it.

And then adding some KITT displays and speech synthesiser.

Tuesday, 3 August 2010

PSION II Datalogging, Bar Graph

Well thanks to some pointers from Boris I got a working bar graph (progress bar) on the Psion II and using machine code too. And I'm over 40. The Psion's RS232 capabilities are really put to the test in OPL though, the buffer fills quicker than the OPL can process it, so I trimmed the amount of data from 64 characters to just 18 without compromising on data. This allows the datalogger to send 8 channels at 10-bit resolution and the Psion to identify the channel to be displayed.

If I go any further with this I want to write more if not all of it in machine code especially to make sure the serial buffer is clear at the beginning of the program, which at the moment is causing problems.
The full set up on the bench. Eventually I want the Psion up in the cockpit of the car (okay, sitting on the dash) or as a hand-held garage diagnostic box and the PIC and so on will be permanently attached to the ECU in the car. Or something like that.

Wooden Car Ramps

Here's my patent wooden 'gentle' car ramps made from treated decking.

Celica ST-165 calipers fitted to my MK1 MR2.