Since then it's taken off with Kaitaia Hunting and Fishing, which is selling the horns for half price to support the initiative, selling 200 with another 150 arriving last week.
Last Thursday about 50 people turned up to a public meeting to hear from Hobman, and Peter Furze, on how the initiative would work.
"It's really got people interested locally and around the country and world," he said.
Hobman said sounding three short blasts from the air horn would let people know there was something suspicious going on and they could keep an eye out and call 111 to alert the police.
He said the idea was so residents could reclaim their streets for the bad guys.
"If you see someone who's up to no good then three blasts of the horn will alert the neighbours, who will look out for someone running or getting away.
"It will make the thief's presence known, and if they are on foot then maybe they can be tracked back to their home. Then phone the police."
It was nothing to do with vigilantism, he said, but about neighbours looking out for each other, as they once did. It was also about helping the police.
Furze told the crowd that three short blasts could be heard form some distance away, and to illustrate got people to sound the horns from two other locations 100m away or more, and they could be clearly hard.
''It's the community coming together to help stop crime. We have to come together to do that and help the police out.
"I'm sick of being worried about the bad guys.''