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AVR-Max Chess Computer

AVR-Max Chess Computer

A minimalist homebrew chess computer

For just a few pounds you can take a microcontroller, add a few pushbuttons and some 7-segment displays to build a chess computer reminiscent of the legendary Mephisto I. The low component count (and no SMDs!) allows the entire machine to be shrunk onto a neat pocket-sized PCB. Despite LED displays it draws just 20 mA and will run until the battery supply falls below 1.9 V.
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Minimal component count
Low power (20 mA @ 3 V)
Battery power using two AAA or AA cells
Nine playing levels
Look-ahead 20 halfmoves
Elo rating approx. 1200-1399
Display of principal variant mode (on/off)
Opening set-up possible
Select black/white at start of play
Change sides during play
Computer can also compete against itself

R1–R8 = 470Ohm
R9–R13 = 10kOhm
C1,C2 = 100nF (lead pitch 0.1” / 2.54mm)
L1 = 10µH (fixed inductor)
LD1–LD4 = SA52-11 (Kingbright), 7-segment LED display, red, common anode, 13.2mm height
T1–T4 = BC559C (or -B)
IC1 = ATmega88P-20PU (Atmel), programmed, Elektor Shop # 081101-41
S1–S11 = push button, 1 make contact, PCB mount, e.g. Multicomp MCDTS6-5N
K1 = 2-way pinheader or 2 solder pins
K2 = 6-way DIL pinheader
K3 = 6-way SIL pinheader, right angled (optional)
Battery holder for 2 AA or 2 AAA batteries
Kit of parts # 081101-71 (see Elektor-Shop,
PCB # 081101-1
Project software, free download # from