While driving down the road did you ever see a temporary roadside digital readout display sign of "This is your speed"? and then it gives the MPH you are driving.
My question is: Does a fuel cell power it? The plastic weatherproof enclosure seems to small to house a regular battery.
If it is a fuel cell would it need hydrogen cartridges? My very limited knowledge for a basic fuel cell power source is: oxygen + hydrogen = D.C. electric energy.