nick@lfcs.ed.ac.uk (Nick Rothwell) (04/12/89)
A while ago, I made a posting describing a Mac MIDI interface we were designing to replace the 200 quid Opcode one I have on loan. I mumbled something about it costing about 10 quid; follow-ups expressed disbelief. Well, the thing is built now, apart from cosmetic details (LEDs). Description: dual-port MIDI interface for the Mac: allows both printer and modem port to be used for input and output. It does the opto-isolating and so on for both ports, and provides a 1MHz clock for both. It's a black box, measuring about 5" deep by 3" wide by 2" high. On one side, there are 4 MIDI ports - 2 in, 2 out. On the other side, two DB9 connectors. Power socket on the back (9V or so), two twin-colour LEDs on the front (they'll go red for MIDI input, green for MIDI output, orange for both. It's gonna be *sexy*). By rough estimates, we've spent about 8 pounds on it. This includes the box, components and connectors. We had a few things lying about: a lot of the resistors, the odd inverter chip, and so on. The cost doesn't include the (external) power supply. More importantly, it doesn't cover the cost of cables to the Mac. 8 pin midi-DINs are worth their weight in gold, and I managed to get these for free. You'd have to talk to your Apple dealer to get these off the shelf, I expect. The price of the box would go up by a couple of quid if we had to buy all the resistors and things, I reckon. We based the design on that by Kirk Austin, replacing a few odds and ends by things mor easily available. If anybody's interested, I can post the MacDrawing of the design. I should also do the sums more carefully to get an accurate rundown of the components and costs. Oh: a recent price list has a dual-port Mac MIDI interface going for something like 225 pounds. Nick. -- Nick Rothwell, Laboratory for Foundations of Computer Science, Edinburgh. nick@lfcs.ed.ac.uk <Atlantic Ocean>!mcvax!ukc!lfcs!nick ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ...while the builders of the cages sleep with bullets, bars and stone, they do not see your road to freedom that you build with flesh and bone.