Memory LED map

This is memory map for any ZX Spectrum type or clone by me & Busy. It can be used also on other 8-bit computers probably. You can build it with either 64 LEDs or 8x8 LED segment. Each of LED represents 1kB of memory, so you can see memory region which CPU actually reads - it's very useful for cracking :-)

Part list:
2 x 74LS138 or MH3205 (clone of LS138)
2 x 74LS04
8 x 330R resistor (anything between 100R and 470R is acceptable)
4 x 100nF ceramic condensator
64 x 2,5 mm red LED or 1 x 8x8 LED segment
some wires
small universal board, or you can use my prototype board.

Place components to universal board (or my prototype PCB), connect all according schematic. Can be mounted internally or can be built into existing external interface (MB-02+, Betadisk, +D ...). I'm recommending 8x8 segment, which can be obtained in some electronics shop or e-bay or so.

Pictures:

Schematic.

My prototype PCB.

My prototype board.

My prototype board - solder side.

Videos:

YouTube link.

YouTube link.

YouTube link.

YouTube link.