Remote Central Locking has Low Range.
#21
Re. security cameras:
The two big problems with security cameras are expense and lighting. Ordinary cameras using "C" mount lenses aren't cheap, and you have to buy a lens separately for them. Professional zoom lenses used in motion picture photography are so unbelievably expensive, cameramen usually hire them. Even commercial zoomers for security can easily be half a grand each, and big lenses for night/IR use much more than that. I speak of motorized lenses of course, with a motor for each of the three functions, iris, zoom tube and focus.
I've wondered how good the lighting is on those I/R cameras with a ring of I/R LEDs around the lens. Hitherto one had to use 150 watt tungsten floods with a 720nM or 900nM I/R filter in front -- these glass filters each were £150, so if these LED jobs work ok., that should be a saving. The tungsten lamps did give a good illumination at quite some distance however.
I think you're on a hiding to nothing getting number plates recorded at night, unless you have a permanent security guard on the control desk and many cameras to boot. Again expense.
Leedsman.
The two big problems with security cameras are expense and lighting. Ordinary cameras using "C" mount lenses aren't cheap, and you have to buy a lens separately for them. Professional zoom lenses used in motion picture photography are so unbelievably expensive, cameramen usually hire them. Even commercial zoomers for security can easily be half a grand each, and big lenses for night/IR use much more than that. I speak of motorized lenses of course, with a motor for each of the three functions, iris, zoom tube and focus.
I've wondered how good the lighting is on those I/R cameras with a ring of I/R LEDs around the lens. Hitherto one had to use 150 watt tungsten floods with a 720nM or 900nM I/R filter in front -- these glass filters each were £150, so if these LED jobs work ok., that should be a saving. The tungsten lamps did give a good illumination at quite some distance however.
I think you're on a hiding to nothing getting number plates recorded at night, unless you have a permanent security guard on the control desk and many cameras to boot. Again expense.
Leedsman.
#22
Professional CCTV installers will fit units like this: Raytec Raymax 25 Illuminator 120° 850-940nm PoE
This is the baby of the family offering a range of up to 30 metres at a price of £180 each.
Apart from the short range, the other problem with IR when it's integrated around the lens is reflections off adjacent structures and spiders webs. This can be so severe as to render the camera useless during the hours of darkness.
A good alternative to providing additional lighting is to use a Day/Night camera. This automatically switches from colour to monochrome and opens the iris to let more light onto the sensor. The results can be quite impressive in areas where there is little ambient light available.
This is an example of a Day/Night camera. The image taken at 01:00 hours is just using the ambient lighting in the area.
Last edited by AlanC; 11-23-2014 at 08:26 AM.
#23
Like the Baxall day night cameras. I put one of those in for my daughter (and it caught a burglar) but the color rendition is not so good as there is no cyan filter in front of the imager. Reds aren't right.
I remember being in on the install of a camera, and those spiders are little devils. It was only in for an hour when we could see clear a web. I reckoned it was the heater for the housing window that attracted them.
I had a feeling that ring of I/R LEDs as sole illumination wouldn't be too brilliant(!)
Leedsman.
I remember being in on the install of a camera, and those spiders are little devils. It was only in for an hour when we could see clear a web. I reckoned it was the heater for the housing window that attracted them.
I had a feeling that ring of I/R LEDs as sole illumination wouldn't be too brilliant(!)
Leedsman.
#24
Re. weak keyfob transmitters:
As with all battery powered hand-held devices, the battery terminal connectors can get an invisible layer of chemical oxidization or sulphation due to minute amounts of the battery's internal chemicals exuding and corroding the contacts. This puts a resistance in series with the battery, spoiling the performance. The watch-batteries in keyfob transmitters are no different.
Using some fine-grade carborundum paper, remove any oxide from both the battery poles AND the connector springs. This is fiddly work. Also measure the battery voltage with your meter. It should be exactly 1.5volt. for most, like silver oxide, but lithium batteries should be at least 3.5volt. New ones are 3.8volt. Any less with such a light load as your meter, the battery is down. Yes, sometimes semi-flat batteries are sold as new, that is due to being unsold for a long time (shelf life) -- so only buy batteries where sales are fast.
Leedsman.
As with all battery powered hand-held devices, the battery terminal connectors can get an invisible layer of chemical oxidization or sulphation due to minute amounts of the battery's internal chemicals exuding and corroding the contacts. This puts a resistance in series with the battery, spoiling the performance. The watch-batteries in keyfob transmitters are no different.
Using some fine-grade carborundum paper, remove any oxide from both the battery poles AND the connector springs. This is fiddly work. Also measure the battery voltage with your meter. It should be exactly 1.5volt. for most, like silver oxide, but lithium batteries should be at least 3.5volt. New ones are 3.8volt. Any less with such a light load as your meter, the battery is down. Yes, sometimes semi-flat batteries are sold as new, that is due to being unsold for a long time (shelf life) -- so only buy batteries where sales are fast.
Leedsman.
#26
No clear answer on this thread. At mo the answer is to check fob battery output is voltage as its said and clean fob to battery contacts. Has anyone found this works.
I forgot all about this thread and just carried on pressing fob up against window.
Receiver seems to be up front near dash or overhead console as normal.
I forgot all about this thread and just carried on pressing fob up against window.
Receiver seems to be up front near dash or overhead console as normal.
#27
Just had a thought -- the microwave aerial in the keyfob sometimes is just a square "ring" of print. If there is a crack in the print, or a bad soldered joint, microwave emission will be poor. Examine with powerful lens and a bright light. If there is a crack in the print, you can bridge it with solder and a fine iron after scraping off the green varnish. Much the same can apply to the microwave receiver in the 'van. Statistically, with all the handling, the keyfob is way ahead in likelihood.
Leedsman.
Leedsman.
#29
In some cases with small prints, I've carefully re-soldered every joint, and whoopee, in a few cases, it's worked...
Leedsman.
n.b. The safety flux in modern wire solder is a bit rubbish at cleaning the joint (although no doubt good for your lungs), so I use a bit of Fluxite as well. dipping the wire-solder end into it.
Leedsman.
n.b. The safety flux in modern wire solder is a bit rubbish at cleaning the joint (although no doubt good for your lungs), so I use a bit of Fluxite as well. dipping the wire-solder end into it.
Last edited by Leedsman; 02-22-2015 at 04:55 AM. Reason: Addition.
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