About the article

Craft Drill Controller

for semi-automated PCB drilling — and more

Craft Drill Controller

Designing and making a printed circuit board (PCB) for a project has many advantages over using strip board, but there is one big disadvantage – drilling the holes. Our Craft Drill Controller takes away some of the tedium of this task by semi-automating the way a 12V mini drill has its speed controlled, so saving time and drill bits!

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Component list


R1,R28,R29 = 100

R2,R6,R9,R10,R15,R18,R21,R24 = 1k

R3 = 15Ω 2W

R4,R30 = 2kΩ2

R5,R12,R13 = 15k

R7,R8,R11,R16,R17,R22,R23 = 4kΩ7

R14,R19 = 2kΩ7

R20, R25 = 10k

R26,R27 = 100k

P1,P2 = 5kΩ linear-law potentiometer

P3,P4 = 10kΩ linear-law potentiometer

P5 = 50kΩ linear-law stereo potentiometer


C1 = 100nF

C2 = 470nF

C3,C4,C7,C8 = 220μF 25V radial electrolytic

C5,C6 = 220nF

C9,C10 = 22nF


D1,D6,D7,D8,D9,D10,D11 = 1N4148

D2,D3,D4,D5,D12,D13 = LED, low current

T1,T4 = BS170

T2,T3,T8,T9,T10,T11= BC560C

T5,T6,T14,T15,T16,T17= BC550C

T7 = TIP122

T12,T13 = BS250P (watch suffix P)

IC1 = L7805CV


S1 = on/off switch, 1 make contact

S2 = on/off switch, 1 make contact

S3 = footswitch, on/off, 1 make contact, see text.

S4 = single-pole changeover switch

S5 = single-pole changeover switch

PCB, ref. 060291-I from ThePCBShop; free artwork download # 060291-1.zip

Front & rear panel artwork files
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