PARTS LIST Train sounds (SG1) Resistors (All 1/4W, 5%): R1 150k R2 330 ohm Capacitors: C1 0.1uF mono Semiconductors: Q1 BC547 NPN transistor COB train sound generator SG1 Miscellaneous: four x N/O pushbuttons; 8 ohm speaker; strip board or equivalent to accept COB PCB and components. PARTS LIST 16-tunes (SG3) Resistors (All 1/4W, 5%): R1 390k Capacitors: C1,2 10uF 16V electrolytic C3 0.1uF mono Semiconductors: Q1 BC547 NPN transistor COB 16-tune sound generator SG3 LED1 5mm LED Miscellaneous: one N/O pushbutton; 8 ohm speaker; strip board or equivalent to accept COB PCB and components. PARTS LIST Ding-dong sound (SG5) Resistors (All 1/4W, 5%): R1 470k R2 150k R3 1M R4 330k Semiconductors: Q1 BC557 PNP transistor Q2 BC547 NPN transistor COB ding-dong sound generator (SG5) Miscellaneous: one N/O pushbutton; 8 ohm speaker; strip board or equivalent to accept COB PCB and components. PARTS LIST Phone sounds (SG2) Resistors (All 1/4W, 5%): R1 100 ohm R2 330k Semiconductors: Q1 BC547 NPN transistor COB phone sounds generator SG2 Miscellaneous: eight x N/O pushbuttons; 8 ohm speaker; strip board or equivalent to accept COB PCB and components. PARTS LIST Gun and siren sounds (SG4) Resistors (All 1/4W, 5%): R1 330k Semiconductors: Q1 BC547 NPN transistor COB gun and siren sound generator SG4 LED1,2 5mm LED Miscellaneous: N/O pushbuttons as required; 8 ohm speaker; strip board or equivalent to accept COB PCB and components. Getting COBs and COB kits Kits of parts for the COB projects described in this article are available from: Alpine Technologies PO Box 934, Mt Waverley 3149. Fax/phone (03) 751 1989. Kits for SG1 and SG2 cost $6.95; for SG3 and SG4, $6.25; and for SG5 $5, including postage. Kits also include documentation, speaker and battery holder, but no batteries. Individual sound generator COBs are also available from: Oatley Electronics 5 Lansdowne Parade, Oatley West, NSW 2223. Phone (02) 579 4985 Postal address (mail orders): PO Box 89, Oatley West NSW 2223. The SG1 and SG2 sound generator COBs cost $3, while those for SG2, SG4 and SG5 cost $2.50.