intel xscale open?
i remember mickey saying on that linuxtag presentation that xscale is no option as there are a lot of NDAs and no way to get open documentation for the xscale processors...?! --Minime 15:59, 13 July 2007 (CEST)
In the gumstix case, this may be irrelevant, as they provide suitable drivers. --Speedevil 16:25, 13 July 2007 (CEST)
gsm included with gprs/gps
i've removed the line/link aobut having to buy an extra gsm module, as this is included with the samsung gprs chip. myfanwy 03:10, 16 July 2007 (CEST)
density of rapidobject polymer material
does anyone have an idea for the density of the polymer rapidobject (or any stereolithography company) uses? i would guess around 900-1,500kg/m^3 - the density of HDPE?
this will produce weight around 30-55g for the case?
I note that nowhere do they state mechanical properties of the material. It may well not be as good as 'normal' phone cases, requiring thicker case, or reinforcement in some manner. --Speedevil 04:08, 17 July 2007 (CEST)
The gumstix boards are designed to stack in one direction - perhaps a ribbon connector can be designed to allow them to be connected in a different orientation, possible making more efficient use of available space. --User:myfanwy
In small quantities - this will be over $50 or so, including attachment of connectors. Custom flex PCBs are expensive. However, this would allow easy integration of buttons, mic, and speaker related electronics. It may not be possible due to bus capacitance requirements. --Speedevil 00:25, 17 July 2007 (CEST)
There are connectors avilable at gumstix for $6 for a pack of 3. I wouldn't know where to start looking for a film ribbon connector, but I'm sure it wouldn't be hugely expensive. The capacitance point is something I hadn't thought of though; we should be able to keep the length to around 30mm - I will look for info to indicate whether this is acceptable or not. myfanwy 01:00, 17 July 2007 (CEST)
The connectors are inexpensive. Assembling them onto a custom flex-PCB is unfortunately not. $50 is probably overkill - for a simple straight connector, but as I understand it, minimum order would be at least 100 bits. As I read the connectors page - you would need an actual proper flex-PCB, board-board connectors are not typically available with flex-cable output options. The JTAG connector flex cable - even if it brings out all 60 wires - which is not certain - doesn't solve the issue entirely. You then need a flex-cable socket and a plug to fit into the extension board. However, this could be on non-flex PCB which is almost free in comparison. --Speedevil 04:08, 17 July 2007 (CEST)
I'm not 100% sure I understand. We can buy a connector which will attach to (say) the motherboard, and another which will attach to (say) the goliath gps/gprs module. As long as we keep the wires very short, we can (with much patience, admittedly) solder a hirose connector to each end of the cable, and there we have a stand-off, flexible connection between the 2 modules. I will look up/calculate the impedance values for the various ribbon cables and see if I can find any acceptable values for signal degradation of the connections - maybe this approach will be suitable, maybe not. myfanwy 09:30, 17 July 2007 (CEST)
You can't solder the connector to the cable - as I understand it, there are two rows on the connector. It needs to be a custom PCB, not a generic cable. On the other hand - the comment about capacitance was when I thought you were envisioning a 5-10cm cable - a 2cm cable is almost certainly not an issue. --Speedevil 11:42, 17 July 2007 (CEST)
There is talk on the gumstix docwiki of a jtag board connecting through the 60-pin hirose, I would assume this is via some sort of ribbon connector, which will be at least as long as we require to connect to another module. myfanwy 01:06, 17 July 2007 (CEST)
stacked modules thickness
i may have made a mistake when modelling the PCB stack. i realise now it is unclear as too how close the components are to each other when assembled. this may need to be revisited myfanwy 01:09, 17 July 2007 (CEST)
goliath gps/gsm module price
myfanwy 02:14, 17 July 2007 (CEST)
It sounded unlikely to be that cheap. Wish you'd been right. Annoyingly this implies that the 'ones' price of the modules are probably in line with sparkfun. $150 for GPRS module, $50 for GPS, $70 for gumstix board. Of course, they will make profit in quantity. --Speedevil 04:08, 17 July 2007 (CEST)