You have made Galvanic cells by combining half cells made of injection bottles:
* A voltage and a current were observed between Al and Fe
*  A LED gave light when it was connected to Pb and PbO₂.
There are not only direct redox reactions between alcohol and a mixture of dichromate and sulfuric acid.
1. Photo: Fill the left half cell with a mixture of methylated spirit and sulfuric acid,
2. the right half cell with a dichromate solution mixed with sulfuric acid.
3. Connect these two cells by a wick (for flow of ions) and
    the carbon electrodes  with a multimeter by two wires.
Observations: A voltage of 0.44 Volt and a current of 42.3 µA are measured.
Explanation:  The alcohol molecules around the negative electrode lose electrons while they are oxidized resulting in aldehyde.
Dichromate ions around the positive electrode take electrons while they are reduced to Cr³⁺ ions.
Electrons flow through the metallic conductors, ions move through the wick.