From: Robin Hollands Subject: TECH: A2D Converters: was Question about VR hardware and authoring kits Date: Tue, 20 May 1997 17:29:55 +0100 Message-ID: <3381D183.21C0@shef.ac.uk> Organization: Automatic Control & Systems Engineering, University of Sheffield Marcia J.Talkmitt wrote: > > >Another nice thing about the PC architecture vs SGI is that is a lot > >easier to add weird hardware. How much does a multi-channel > >digital+d/a-a/d board run for an SGI box? Whilst I am still (just) a dedicated PC user, the Windows NT platform has put a halt to much of my 'weird hardware' tinkering. Since the opertaing systems seems to catch all the 'out' commands which I write to both bus-based and port based devices - adding weird hardware is really difficult (I can't use any of my A/D converter boards for example). My way around this was to build a 16-channel, 12-bit A/D converter which works over the RS232 serial link at 9600 baud, and is fast enough for my applications. The component cost is around 100 which probably equals $100 in US component prices (you guys get that stuff cheap!) After Linda backed up the original O2 posting, a did some checking, and I'm definitely tempted by an O2 platform for my next academic project. The cost of the cheapest O2 works out slightly less than my Integraph TDZ-310, but most the performance specs seem about 30%-50% higher. Incidentally, the serial port analogue to digital converter will obviously work with any machine with RS232, and allow access to all sorts of homebrewed hardware. Whilst I may include in any future versions of the 'Virtual Reality Homebrewer's Handbook" (to get a wider customer base), anyone that wants the circuit diagram should just email me. Along the same lines - any homebrewer who wants a circuit diagram for a $25 16-channel 8-bit printer port based A/D can also drop a line... Cheers, Robin Email: r.hollands@sheffield.ac.uk WWW: http://www.shef.ac.uk/~vrmbg/staff/rjh BOOK: http://www.shef.ac.uk/~vrmbg/vrhmhb