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SMD Soldering Challenge

The purpose of the SMD Soldering Challenge is to provide people the opportunity to get some experience with smaller surface mount devices, so as to decide for themselves how small a part they feel comfortable working with on future projects. Since there are significant cost benefits with quantity, I decided to buy enough parts for 100 "kits", each of which contains a sample of many tiny SMD parts, and sell the kits for cost(ish). The schematics and layout were done with gEDA and PCB.

Note: the purpose of this kit is the soldering, not the results. I designed a circuit that happens to work if all goes well, but I don't guarantee it. There are all sorts of things that can go wrong from the time the parts get here (my house) to the time you finish the circuit.

Ordering Information

Currently Out of Stock

Design Files

Actual board size
0.5" x 0.5"
Photo of completed board
(click for larger view, about 180k each)

Note that for each oscillator, only one of the two capacitors is to be populated. C4/C5 results in about 400Hz, C2/C3 results in about 2200Hz. This circuit is sensistive to injection locking, hence the alternatives. Also, R5 and R6 may be populated with 1k resistors instead of the 150s.

Bill of Materials
RefDes Qty Footprint $/100 $/kit Notes Pitch (mm) Manuf. Mfg Partno
C2-5201005$7.90$0.160.01uF0.50 MurataGRM022R60J103KE19D
R1,R220201$3.65$0.07100k1.00 RohmMCR006YZPF1003
R3-440402$1.30$0.051k2.00 KOA SpeerRK73H1ETTP1001F
R5-620402$1.30$0.031502.00 KOA SpeerRK73H1ETTP1500F
LED1-220603$6.60$0.13Red LED3.00 LITE-ONLTST-C190CKT
C110805$3.32$0.031uF4.00 EPCOSB37941K8105K62
Q21SOT-416$9.10$0.09NPN0.50 ON SemiDTC144EET1
Q11SOT-323$7.60$0.08NPN0.65 Micro CommBC847CW-TP
U11tvsop-14$27.72$0.28Hex Inv0.40 TISN74AHC14DGVR
U21US-8$23.00$0.23Dual XOR0.50 FairchildNC7WZ86K8X_Q
1PCB$58.48$0.582S/2M/2S PCB-Pool
1S/H$8.95$0.09(to get parts to me) Digikey, Mouser
$1.83Total

Note: You only populate C2 or C4, but not both. You only populate C3 or C5, but not both.

Note: there are two extra 1k resistors. R5-6 can optionally be 1k, they're just current limiters for the LEDs. You'll have two 0402s left over after you build the board.


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  Copyright 2006   by DJ Delorie     Updated Nov 2006