phase_dancer
Bluelight Crew
- Joined
- Mar 12, 2001
- Messages
- 6,179
Ultrasonic Deterrent
These are about $45-00, but could easily be built for around $10-15 in parts. Small disposable caseless types could be employed with suitable concealment, or simply be carried in the pocket. I'm not saying the device wouldn't rouse the attention of the dog owner/trainer, but how easy would it be to pick the person carrying the device in a crowd of hundreds? Besides, they might be carrying it simply to ward off the neighbors dog when walking home.
I can draw up a circuit diagram if anyone is keen to build one; only to be used for repelling dangerous dogs of course.
For the technical boffins, the output should be sinusoidal, and the level above 120db @1 meter, if possible. The range of frequencies (sweep) of the commercial models is generally between 21-26kHz. A report also listed 16kHz, but this was possibly due to poor design.
Circuit is simple. A VCA can be used to drive a sweeping oscillator. Peizo transducers are very efficient (energy in to energy out), and generally have a very high maximum frequency response. It may be worth checking an old mobile phone for a suitable second hand transducer.
All components are available through one of the larger electronics parts shops. Nothing should be expensive, so shop around if you have to.
Health warnings have been expressed concerning long term exposure to ultrasonic frequencies. For you conscientious objectors, the ultrasonics radiation warning label is a square containing cascading crescents, growing from a point source.
I wish to state that I don't recommend anyone break any law, particularly when it may have been erroneously viewed that I'm encouraging the serious crime of interfering with an officer carrying out his duty. I am NOT. A cab is a much safer all-round option if you can afford it.
However it may turn out that if the emitted ultrasonic field was localised to around your body, and levels of emision were below health concerns (~60-90db), it may turn out to easily defended in court. But then I'm no Lawyer.
As far as Bluelight is concerned, the most crucial thing is the reports of people necking several pills when confronted by police dogs.
This is a classic example of policy incompatibility; Zero Tolerance is clashing head-on with Harm Reduction. If you don't buy, sell or use drugs, then there may be little to be concerned about sniffer patrols, apart perhaps from the indignant feeling of personal invasion. The ethical issues have been covered before, as have concerns regarding users resorting to unsafe practices - desperation? Or feeling in their own mind it's "safer" to risk short-term safety- rather than to face the possible outcomes from getting busted.
We should continue to focus on this important issue, which sometimes feels like a step backwards for HM workers. They're generally busy enough without extra work assisting users who have been faced with this catch 22.
These are about $45-00, but could easily be built for around $10-15 in parts. Small disposable caseless types could be employed with suitable concealment, or simply be carried in the pocket. I'm not saying the device wouldn't rouse the attention of the dog owner/trainer, but how easy would it be to pick the person carrying the device in a crowd of hundreds? Besides, they might be carrying it simply to ward off the neighbors dog when walking home.
I can draw up a circuit diagram if anyone is keen to build one; only to be used for repelling dangerous dogs of course.
For the technical boffins, the output should be sinusoidal, and the level above 120db @1 meter, if possible. The range of frequencies (sweep) of the commercial models is generally between 21-26kHz. A report also listed 16kHz, but this was possibly due to poor design.
Circuit is simple. A VCA can be used to drive a sweeping oscillator. Peizo transducers are very efficient (energy in to energy out), and generally have a very high maximum frequency response. It may be worth checking an old mobile phone for a suitable second hand transducer.
All components are available through one of the larger electronics parts shops. Nothing should be expensive, so shop around if you have to.
Health warnings have been expressed concerning long term exposure to ultrasonic frequencies. For you conscientious objectors, the ultrasonics radiation warning label is a square containing cascading crescents, growing from a point source.
I wish to state that I don't recommend anyone break any law, particularly when it may have been erroneously viewed that I'm encouraging the serious crime of interfering with an officer carrying out his duty. I am NOT. A cab is a much safer all-round option if you can afford it.
However it may turn out that if the emitted ultrasonic field was localised to around your body, and levels of emision were below health concerns (~60-90db), it may turn out to easily defended in court. But then I'm no Lawyer.
As far as Bluelight is concerned, the most crucial thing is the reports of people necking several pills when confronted by police dogs.
This is a classic example of policy incompatibility; Zero Tolerance is clashing head-on with Harm Reduction. If you don't buy, sell or use drugs, then there may be little to be concerned about sniffer patrols, apart perhaps from the indignant feeling of personal invasion. The ethical issues have been covered before, as have concerns regarding users resorting to unsafe practices - desperation? Or feeling in their own mind it's "safer" to risk short-term safety- rather than to face the possible outcomes from getting busted.
We should continue to focus on this important issue, which sometimes feels like a step backwards for HM workers. They're generally busy enough without extra work assisting users who have been faced with this catch 22.
I would be happy to proof read it for you (Bluelight IM me if you want).
