| ??? 11/05/09 15:07 Read: times |
#170459 - but entirely too expensive ... Responding to: ???'s previous message |
Per Westermark said:
The shown clock had 10 characters high, 11 characters wide.
If using 2x2 LED for each character, you would need 20*22 LED, i.e. 3*3 = 9 LED modules. If each 8x8 LED module costs $4, the cost would be $36. Cost for printing the characters on a standard OH film < $1. I've got some experience with printing on transparency, and I'll tell you right now, inkjet and laser output from current-generation printers is entirely too transparent. Not since the early laser printers, e.g. HP LaserJet-II/III have printers produced fairly dense and nearly opaque output. Depending on processor selected, you could manage without any external shift registers.
Not costly at all. Upgrading to 3x3 LED for each character, you would need 30*33 LED, i.e. 4x5 LED modules - $80. Still not too expensive for a cool clock. But entirely too costly for a student project. But why be so specific? Shouldn't we leave it for a student to look at the problem and figure out a reasonable solution and what the cost would be? Yes, we should ... but keep in mind that students, generally speaking, don't want to spend more on a project than on a case of beer. RE |
