= Solution
Use \b[eight parallel 8:1 <multiplexers> and one shared three-<bit> <binary counter>]. If $d_{i,j}$ is <bit> $j$ from sensor $i$, connect $d_{0,j},\ldots,d_{7,j}$ to <multiplexer> $j$. Connect all selection inputs to the <binary counter> outputs. Then data line $j$ carries $d_{q,j}$, so all eight data lines belong to the same selected sensor. Send the three counter outputs to the receiver as the address lines as well.
\Image[/past-exam-of-the-year-1-of-the-computer-science-course-of-the-university-of-oxford/2016/digital-main-sensor-multiplex.png]
{title=One shared <binary counter> selects the same sensor in eight parallel <multiplexers>}
After reset the receiver sees sensors $0,1,\ldots,7,0,\ldots$, one per <clock period>. Sample the data and address only after the <binary counter> and <multiplexers> have settled, for example on the opposite <clock edge> with a sufficiently long <clock period>. Changing addresses can otherwise cause transient <logic hazards>. The transmitter uses \b[eleven signal lines], apart from any shared clock or reset connection.
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