here is the homemade stencil before etching.
And here is the soldered board after I fixed the minor issues. The TPS2044 has been bypassed.
The BOM for this one has been reduced to the following:
ref | value | Qty |
C1 | 680pF | 1 |
C2 | 0,01µF | 1 |
C3 | 100µF | 1 |
C4 | 0,1µF | 1 |
C5 | 10µF | 1 |
C6,C7 | 33pF | 2 |
C8 | 4,7µF | 1 |
C9,C10 | 1µF | 2 |
C11 | 0,1µF | 1 |
CON1 | USB-MINI-B | 1 |
D1,D2 | 4148 | 2 |
IC1 | NE556 | 1 |
IC2,IC3 | CP2102 | 2 |
J1 | USB_2 | 1 |
P1,P2 | CONN_8 | 2 |
R1 | 1k | 1 |
R2 | 10k | 1 |
R3 | 1,5k | 1 |
R4..R11 | 27 | 8 |
R12..R15 | 15k | 4 |
R16 | 2,2k | 1 |
R17 | 15k | 1 |
RV1 | 100k | 1 |
U1,U2 | SN75240 | 2 |
U3 | TUSB2036 | 1 |
X1 | 6MHz | 1 |
The definitive board will use one or two CP2108 to allow up to 4 or 8 hashing units.