Logic Probe Case with Red / Black Croc. Clips Power Cable.
Logic Probe Case (open) with Circuit.
The circuit was soldered onto a 9 x 37 hole vero-board which was cut to size using a hacksaw then filed to smooth the edges. This gave 9 fully conducting rows of holed copper. A 'spot face cutter' tool was required to 'halve-drill' holes in the vero-board to stop the whole track row length conducting. For two sides of a IC for example.
Spare 2-way strips of ribbon cable was used to connect the circuit board to the 4 LED's, and 2-way switch. These were covered in insulating tape to stop short circuits between the board and components. The 2-way insulated power cable terminated in the circuit board. And one final wire went to the probe its self.
Resistors - Min Res - ALL 9p each R1,8 10k (Brown Black Orange) 3 off (M10K) R2,4 2.2k (Red Red Red) 3 off (M2K2) R5,10,11 4.7k (Yellow Violet Red) 3 off (M4K7) R6,13 8.2k (Grey Red Red) 2 off (M8K2) R7 470k (Yellow Violet Yellow) (M470K) R9 270W (Red Violet Brown) (M270R) R12 16k (Brown Blue Orange) (M16K) Colour Code Convertor PC Windows Programme. Very good and easy to us. I recommend it! Capacitors C1,2 10 nF (104Z) Ceramic 10 2 off (WX44X) - 7p All ceramics are measured in pico farads. So 104 = 10,000 pico farads = 10 nano farads. See Engineering Notations for description of measurements. C3 4.7 µF 16V Tantalum Bead (WW35) - 45p C4 10 µF 10V Electrolytic (JA75S) - 8p To smooth spikes from the circuit power supply. Semiconductors IC1 LM393N Voltage Comparator (UH30H) - 54p IC2 555 Timer - NE555N (GH66W) - 37p D1 Diode (to protect circuit in case power leads are connected back to front). D2,5 5mm RED LED's (WL29E) - 12p With 5mm LED Clips 4 off (YY40T) - 8p [OR] 5mm LED Cliplite Covers 4 off (YH54J) - 21p [OR] 5mm LED Chrome Bezzels, top quality 4 off (N89AX) - 87p Miscellaneous LK1-11 Wire links between circuit tracks. SW1 SPDT Ultra Min Tggle - 5.2mm Mounting Hole (FH98G) - £1.49 CN1 Gold Croc Clip Red (FS53J) - 52p CN2 Gold Croc Clip Black (FS55K) - 52p One Meter of 2-way Cable for power lead. Small moulded black plastic case (FT31) - 99p 124mm long by 33mm wide by 30mm deep Logic Probe Tip - Long M3 bolt Legends (white transfer writing for case). Vero-board, 81 x 14 holes - Stripboard (FL17T) - £4.99
All components available from Maplin Electronics on-line (through the Post or from there 40 UK Shops). The Logic Probe project was published in the Maplin Magazine.
Maplin Electronics - postal retailer with shops of 12,000 quality Electronic Components and Items, large stock, own catalogue. P&P £2.50, free over £35 incl. VAT.