0100,0100,0100On 28 Nov 2001, at 16:25, sleeper75se@yahoo.se wrote: 7F00,0000,0000> Hi Andreas ! 7F00,0000,0000> my computer doesn't have an IrDA port. What do I do? :-) But the > Microchip device looks perfect for the job if you want wireless > communication. It certainly feels a lot safer than a opto-coupler. > But I think IrDA is for the advanced systems and optical fiber for > the simple ones! If you don't have IrDA already in your PC, chances are high that there's a jumper on your motherboard where you can directly attach a IrDA transceiver. There are several plans around how to upgrade your PC to IrDA if this jumper is available.Symbol 7F00,0000,0000Arial> > I've done a lot of thinking about this (I'm home on sick-leave today) > so please let me tell you what I came up with: > > The MCP2150 costs $5.70 in quantities of 100 or more, at Arrow > electronics you pay $6 for single items. Great that you found out the exact price :) > I just found another device 7F00,0000,0000> that might work though, HSDL 7000. It is not as capable as the > Microchip IC, but it is much cheaper, you can get it for about $2.90. > It is specified for use in medical applications and can be connected > directly to an UART, though it needs a baud-rate clock (baud-rate x > 16) to work. To that, you must add the cost of the tranceiver > LED/photo-diode. HSDL 1001 might be a good choice for $4 at Arrow > electronics. I think the HSDL doesn't provide the protocol. It only provides the physical layer, transforming the usual USART data into the slightly different timing (1/16th duty cycle) that IrDA transceivers need in order to operate. The problem then is to include the protocol in the microcontroller. This is complicated and/or expansive (if we buy the protocol layer from somebody). Also, in IrDA the BAUD-Rate changes. First it's always 9600, then it can be changed to something higher, up to 115k.Symbol 7F00,0000,0000Arial> > Datasheets can be found here > http://literature.agilent.com/litweb/pdf/5965-5363E.pdf > and here http://literature.agilent.com/litweb/pdf/5964-9278E.pdf > > So the IrDA solution is $6.90 with Agilent and $9.70 with Microchip > IC's, not counting the cost for adding IrDA support if your PC does > not have it (another $7-$10 if you use the same setup on the PC-side). Exactly the same setup is impossible for the Microchip solution. For motherboards with IrDA jumpers the upgrade on the PC side will cost $4 (HSDL1001 or similar).Symbol 7F00,0000,0000Arial> One note: A HSDL1001 eats 100mA of current, so it may not be the > optimal solution for a battery operated device. > > Now, does communication with the EEG-device really need to be > bidirectional? I think it would be a nice feature to have. Also for later improvements and so on.Symbol 7F00,0000,0000Arial> > Looking back at the fiber-solution, the Toslink transmitter is just a > LED with a driver circuit. For the speeds we are looking at > (115200bps or less) you can replace it with a simple flat-top LED and > the cost for the transmitter drops to 20 cents. Put together with the > transistors and resistors (about $.20 each, total of $1.5) the photo > diode ($.50) DSUB connector ($1.50) and nylon fiber ($2.50/meter) you > get $3.70 or more, depending on the length of the cable. But then you have to due all kinds of things like glueing the LED to the fibre and so on which aren't perfect or professional :) I'd prefer 5$ more to get a IrDA compliant solution that can interface to every other IrDA device in the world. If we want to design a really grassroot device with our own fibre interface we could also use optocouplers (like in the current design). I'm thinking about IrDA because it might save us from conducting some difficult safety tests needed for medical devices otherwise. (In germany you'd have to test the whole system - eeg, computer,software to comply to some complicated norms). Also it's convenient and modern and interesting.Symbol 7F00,0000,0000Arial> > I know you guys have been working on this for a long time, so I'm > definitely not the one to tell you what to do or not. I must admit > the difference is not as large as I thought it would be, and in a > $100 project, $3 may not matter much. On the other hand, it is > interesting to discuss different solutions. :-) Of course :-) Nice to have somebody to discuss details with. 7F00,0000,0000> > > Be well, You also be well, Moritz ---------------------- Moritz von Buttlar moritz@v...