RAIN TRACKER™ RT-50, UNIVERSAL, ACCESSORY, RAIN-SENSING, AUTOMATIC, WINDSCREEN-WIPER SPEED CONTROLLER FOR VIRTUALLY ANY VEHICLE, INCLUDING THOSE WITH 6 VOLT ELECTRICS

by Nigel A. Skeet

When I get around to it, the front windscreen wiper system, of my 1973 VW "1600" Type 2 Westfalia Continental campervan, will be further upgraded, using an OEDES Rain Tracker™ RT-50, rain-sensing, universal, accessory, automatic, windscreen-wiper speed controller, which I obtained several months ago, after discovering this product by accident on the Internet, whilst researching a further magazine technical article (i.e. a follow-on, from my 1968~79 VW Type 2 rear-window wiper article, in 1996!), about windscreen wiper & washer system upgrades, for eventual publication in Transporter Talk (bi-monthly magazine, of the British VW Type 2 Owners' Club, of which I've been a member, since November 1995), and possibly also VW Camper & Commercial.

http://www.raintracker.com 
http://www.rainsensors.com 

After further research and correspondence with the OEDES company founder & president, Rein Teder, I prepared a detailed, separate article and a brief summary, as follows:

Nigel A. Skeet, "Rain Tracker™ RT­50, Universal, Rain-Sensing, Automatic Windscreen-Wiper Controller", Transporter Talk, Issue 77, June 2005, pp38~43.

Nigel A. Skeet, "Auto Wipers?", Technical Forum, Volkswagen Driver, Issue 62, Volume 6, Number 2, July 2005, p62

The information on OEDES's Internet website, pertaining to the Rain Tracker™ RT-50 product specifically, and rain sensors in general, is rather fragmented and dispersed in various nooks and crannies, so although the Transporter Talk article itself, doesn't include any illustrations (The editor had insufficient space to publish them!), the various URLs which are interspersed between the paragraphs, give a guided tour of the relevant sections, in a coherent sequence. The article also summarises additional information, obtained directly from Rein Teder and other sources, not included on the website. When I get the opportunity, I shall try to append a scan of the advertising leaflet and some photographs I took of the kit.

Normally, a single, complete Rain Tracker™ RT-50 kit, retails on-line, at US$149 plus shipping, to individual purchasers, but various discount schemes are available to wholesalers, jobbers & retailers, fleet operators and motor clubs. Details are available from Chad Erickson (e-mail: chad@oedes.com), the Account Manager, at OEDES, in Eden Prairie, Minnesota, USA.

Up-to-date currency conversion rates, can be found at the following Internet website URL:

http://www.xe.com/ucc/ 

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RAIN TRACKER™ RT-50, WINDSCREEN-WIPER CONTROLLER KIT

The OEDES Rain Tracker™ RT-50, rain-sensing, automatic windscreen wiper speed controller kit (part No. 800-0100-011), comprises the following items:

Rain Tracker™ Model RT-50 Installation Manual (document No. 001-1122-011B).

Rain Tracker™ Operating Instruction's double-sided card (document No. 001-1116-011A).

One window sticker (retained by air pressure and/or static electricity), bearing the legend, "Rain Tracker™: Enjoy the Safety of Hands-Free Wipers".

One black control module, of dimensions 133 mm (including two 10 mm long mounting-screw lugs, at diagonally opposite corners) x 45 mm x 21 mm depth, with 3-way, 4-way & 10-way male sockets, plus 4-way DIP switches.

One black coloured rain sensor, of dimensions 45 mm x 45 mm x 21 mm depth (including detachable, windscreen-mounting coupler), with 3-way male socket.

One sachet containing an isopropyl alcohol (i.e. isopropanol) impregnated, windscreen cleaning cloth.

One thin, black, three-core cable, of 2760 mm (i.e. 108½ inches – just over 9 feet or 3 yards) overall length (including 35 mm long, moulded-on female plugs, at either end), to connect rain sensor to control module.

Ten multi-filament, single-core, coloured cables (pink, orange, purple, blue, green, white, yellow, grey, red & black), all of 455 mm (i.e. 18 inches) length, terminated by a single, 15 mm long, 10-way, female plug, to interface the control module, with the vehicle's standard windscreen wiper system.

One black, single-pole, single-throw, panel-mounted rocker switch, with two soldered, multi-filament, single-core, grey cables, of 295 mm (i.e. 11½ inches) length.

Two blue, snap-lock, electrical connectors.

One crimp-type, ring connector.

Two crimp-type, closed-end-splice, electrical connectors.

Three crimp-type, butt-splice, electrical connectors.

Three 140 mm plastic cable ties.

One packet of two IN4002 diodes and ten assorted 5% tolerance resistors, as follows:

Colour Code Bands Resistance
blue, grey, black, gold 68 ± 5% ohms
red, red, brown, gold 220 ± 5% ohms
orange, orange, brown, gold 330 ± 5% ohms
orange, white, brown, gold 390 ± 5% ohms
blue, grey, brown, gold 680 ± 5% ohms
brown, black, red, gold 1,000 ± 5% ohms
orange, orange, red, gold 3,300 ± 5% ohms
orange, white, red, gold 3,900 ± 5% ohms
red, red, orange, gold 22,000 ± 5% ohms
yellow, violet, orange, gold 47,000 ± 5% ohms

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Nigel A. Skeet, "Auto Wipers?", Technical Forum, Volkswagen Driver, Issue 62, Volume 6, Number 2, July 2005, p62

For the past few years, rain-sensing, automatic, windscreen wipers, have been available as an expensive factory-fitted option, on various VW & Audi models. These days, almost any vehicle, both old and new, can benefit from this technology, by retro-fitting an OEDES Rain Tracker™ RT-50 accessory kit, which includes everything needed to complete the installation.

The Rain Tracker™ works in tandem with the vehicle's standard windscreen-wiper system, whose normal, manual functions (e.g. low-speed, high-speed, intermittent & park) are unaffected by the installation. When the additional facility of rain-sensed, automatic windscreen wiper control is desired, this is immediately conferred, by operating a simple on/off switch, mounted in or under the dashboard, console or other convenient location.

The Rain Tracker™ RT-50, comes as a complete kit (including the 133 mm x 45 mm x 21 mm control module & 45 mm x 45 mm x 21 mm rain sensor), with everything needed to upgrade almost any car, truck or van, to hands-free wipers. This is the result of years of research and experience, with hundreds of different wiper systems. An experienced technician might install the Rain Tracker™ system, in as little as twenty minutes, but the DIY owner would be advised to allow at least one hour. If one has ever installed a car stereo or other automotive electronic device, one will find the Rain Tracker™ installation to be very straightforward.

The 45 mm square rain sensor, uses beams of infra-red light, to sense how much water is deposited on the windscreen and the controller constantly adjusts the wiper sweep frequency, to keep the windscreen clear; ranging from completely off, to high speed, via intermittent and slow; using an algorithm (i.e. a special computer program) to mimic idealised driver response, so that the wipers respond quickly, without being jerky or erratic.

In contrast to the expensive factory-fitted systems, the Rain Tracker™ rain sensor, can be readily removed in the event of subsequent windscreen breakage and afterwards refitted to the new windscreen, using an inexpensive replacement coupler, which is available as a separate item.

At present, the Rain Tracker™ is only available by direct Internet purchase, priced at US$149 (about £80), plus shipping, from OEDES in the USA, but it might soon be obtainable from car accessory shops and mail-order companies in Great Britain, details of which, will ultimately be published on the website, but contact them direct for up-to-date information.

Opto-Electronic Design Inc., 6440 Flying Cloud Drive, Suite 207, Eden Prairie, Minnesota, MN 55344, USA.
Tel. (International) +1 952 943 2378
Fax. (International) +1 952 943 1020
e-mail: info@raintracker.com
http://www.raintracker.com 
e-mail: info@oedes.com

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Nigel A. Skeet, "Rain Tracker™ RT­50, Universal, Rain-Sensing, Automatic Windscreen-Wiper Controller", Transporter Talk, Issue 77, June 2005, pp38~43:

One factor which has a major influence on effective windscreen wiping, is the frequency of wiper sweeps, dependent upon the incidence of raindrops or other precipitation (i.e. snow, sleet, mist or fog). If the windscreen wipers sweep too frequently, the wiper blades tend to smear the glass, accompanied by the irritation of a squeaking noise and increased blade-wear rate. Too low a frequency, results in there being an excessive number of water droplets blocking one's vision.

http://auto.howstuffworks.com/wiper.htm 

Although some cars have an intermittent wiper facility, of which even fewer have a driver-adjustable sweep frequency, the process of constantly adjusting the wiper sweep rate, to cope with changing conditions (e.g. alterations in vehicle speed, relative wind velocity, precipitation rate & droplet size, plus sudden deluges of road spray, from passing lorries and buses), is both fatiguing and distracting; especially for disabled drivers with hand controls, such as a hand-operated brake and/or throttle.

Further considerations also apply, to drivers of even older cars, whose wiper switches are located on the dashboard (e.g. Triumph Toledo and pre-1973 VW Type 2s), rather than incorporated into steering-column mounted, combination stalk-switches. The difficulties are particularly acute, when driving at night on unlit roads, owing to the dashboard-mounted wiper switch being virtually invisible, as I and my acquaintances, have personally experienced, with a 1974 Triumph Toledo and various 1968~72 VW Type 2s!

Since the mid-1990s, more than 2 million vehicles (Bob Weber, "Water Ballet: The first drops of rain put latest generation of windshield wipers in motion", Tribune, Monday, 2nd June 2003), have been equipped with automatic, rain-sensing wipers, either factory-fitted as standard, or as an extra-cost option. This effectively eliminates the aforementioned problems and consequently reduces both driver distraction and fatigue, which leads to a reduced risk of accidents.

In the USA, the NSTSA (The National Highway Traffic Safety Administration) is said to have implicated driver distraction alone, in at least 26% of fatal accidents, during a one-year period. A recent article in the British national press (i.e. "The dashboard danger", Daily Mail, Thursday, 28th April 2005, p31), also echoes this view; saying that adjusting controls such as light switches, almost doubled from 0•75 to 1•45 seconds, the time taken, to react to a hazard and activate the brakes in an emergency.

The Rain Tracker™ RT­50, is a universal, after-market, rain-sensing, automatic, windscreen wiper control system, intended for DIY retro-fitment, to virtually any motor vehicle, having a 12V electrical supply. It could also potentially be used, with vehicles having a 6V or 24V electrical system, in conjunction with some readily available, supplementary circuitry, to provide a low-current 12V supply to the control module.

The Rain Tracker™ RT­50 controller, works in tandem with the vehicle's standard windscreen-wiper system, whose normal, manual wiper functions (e.g. low-speed, high-speed, intermittent & park) are unaffected by the installation. When the additional facility of rain-sensed, automatic windscreen wiper control is desired, this is immediately conferred by operating a simple, SPST on/off switch, mounted in or under the dashboard, console or other convenient location.

http://www.raintracker.com 

http://www.raintracker.com/how_RT_works.htm 

http://www.raintracker.com/FAQs.htm 

The Rain Tracker™ rain sensor uses beams of infra-red light (wavelength = 880 nanometres), to sense how much water is deposited on the windscreen. It constantly adjusts the speed of the wipers, so that they run just often enough, to keep the windscreen clear; ranging from completely off, via intermittent, to slow and high speed (most applications). It uses an algorithm (i.e. a special computer program) to mimic idealised driver response, controlling the wipers in a way that responds quickly, but which is never jerky or erratic.

http://www.rainsensors.com 

http://www.rainsensors.com/performance_issues.htm 

http://www.rainsensors.com/Optical.htm 

The relatively small (i.e. 1¾" x 1¾" or 45 mm x 45 mm) Rain Tracker™ rain sensor, mounts on the inside surface of the windscreen, corresponding to a region which is swept by the wipers. This is typically behind the interior rear-view mirror, where it is least likely to obscure the driver's vision, but can reasonably be mounted near the bottom or on either side of the windscreen.

In the event of windscreen breakage, the rain sensor can be readily removed and afterwards be refitted to the replacement windscreen. Although it might be possible to salvage the polycarbonate coupler and simply replace the double-sided adhesive pad, it would normally be more practical to purchase a replacement coupler, which is available as a separate item. In fact, some owners might seek peace of mind, by purchasing a spare coupler kit (coupler & windscreen-glass cleaner), together with their Rain Tracker RT-50, in much the same way, as some carry a spare double-sided adhesive pad, to re-attach the windscreen-glass-mounted, rear-view mirror!

The Rain Tracker™ RT-50, comes as a complete kit (including the 133 mm x 45 mm x 21 mm control module & 45 mm x 45 mm x 21 mm rain sensor), with everything needed to upgrade almost any car, truck or van, to hands-free wipers. This is the result of years of research and experience, with hundreds of different wiper systems. An experienced technician might install the Rain Tracker™ system, in as little as twenty minutes, but the DIY owner would be advised to allow at least one hour. If one has ever installed a car stereo or other automotive electronic device, one will find the Rain Tracker™ installation to be very straightforward.

http://www.raintracker.com/installation.htm 

http://www.raintracker.com/pages/Typical_Installation.htm 

http://www.raintracker.com/pages/Typical_installation_contd.htm 

Most windscreen wiper system circuits are quite straight forward, being of either the simple standard "HSS" (i.e. "Hot-Side or Live-Side Switching") or "GSS" (i.e. "Ground-Side or Earth-Side Switching") types, which require just a few electrical connections to be made, as clearly illustrated in the following instruction sheets, which accompanying the kit:

http://www.raintracker.com/Compatibility/RT-50_Install.pdf 

At sometime in the near future, I shall be retro-fitting a Rain Tracker™ RT-50 system, to my own 1973 VW Type 2 and hence, have already established for my own purposes, that the T2, 1968~79 VW Type 2, windscreen wiper system circuits are of the "HSS" type. I have already drafted some simplified wiper system circuit diagrams, for the 1968~72 & 1973~79 VW Type 2, if anyone is interested! From what I have seen of other VW & Audi wiper circuits, I anticipate that those of the T1, T3, T4 & T5 generations of VW Type 2, will probably also be of the "HSS" type.

If by chance, the DIY owner, does not possess their own copy, of an owner's handbook or workshop manual, containing the relevant, electrical circuit wiring diagram for their vehicle, there are already hundreds of vehicle-specific installation diagrams, guidance notes and trouble-shooting procedures, on the OEDES Internet website:

http://www.raintracker.com/Compatibility/Compatibility.htm 

In the unlikely event that the installed system does not function correctly, there are comprehensive trouble-shooting procedures, which can be downloaded from OEDESs Internet website; of which the following example, applies to the simple "HSS" and "GSS" type systems:

http://www.raintracker.com/Compatibility/001-1123-001_RT-50_TS_MS.pdf 

Some windscreen wiper systems, which are more sophisticated, require external components (usually one or more, commonly available resistors and/or diodes, which are included in the kit) to be incorporated into the system circuitry. Some BMWs, plus a few North American Chrysler, Ford and General Motors car models, fall into this category, for which there are also a comprehensive set of vehicle-specific installation diagrams and guidance notes.

Dependent upon customer demand, further vehicle-specific, electrical circuit wiring diagrams, guidance notes (including details of the windscreen-wiper system wiring colours) and trouble-shooting procedures, will be added to the already extensive database, which is periodically updated, as OEDES become aware of additional vehicle marques & models, together with their associated windscreen-wiper circuits and wiring colours.

http://www.oedes.com/installation_services.htm 

If the required information is not already archived on the Internet website, customers are invited to seek technical assistance from the personnel at OEDES; preferably via e­mail, but enquiries could also be made by fax, telephone or letter. If considered appropriate by retailers, alternative ways of providing detailed technical support, at the point of sale, would be investigated, which might include a CD­ROM.

The Rain Tracker™ RT-50 rain sensor, is compatible with most windscreen materials and thicknesses, currently in use; including the zone-toughened, laminated, tinted, solar-absorbing and electrically heated (i.e. multi-filament-wire conductor mesh) varieties, with thicknesses upto ¼ inch. However, there are a small minority of windscreens or regions of windscreens which compromise the operation of a rain sensor.

Over the years, windscreen manufacturers, have been progressively improving the infra-red filtering efficiency of their solar-absorbing glass, to minimise a vehicle's solar gain by the "green house effect", when parked outdoors in intense sunlight. High-performance, solar-absorbing glass, passes about 1% of the Rain Tracker™ optical rain-sensor's infra-red light signal, on its round trip through the glass, which is sufficient for it to function.

Many rain sensors, of a type which are factory-fitted to new cars, cannot function with this type of glass, prompting the vehicle manufacturers, to specify special windscreens. This compromises the solar performance of the glass, as well as complicating windscreen replacement. The Rain Tracker™ rain sensor, is compatible with high-performance, solar-absorbing glass, as well as standard tinted and clear glass.

However, the Rain Tracker™ rain sensor, is not compatible, with the relatively rare solar-reflective windscreens (e.g. "Sun-Gate" and KOOL-LOF brands), which can be identified by their external coating, whose edges are normally visible, about an inch or so from the outer edge of the windscreen glass. In the temperate climates of Great Britain and Northern Europe, it is debatable whether any vehicles, will have been equipped with this type of windscreen.

Some windscreens have a coloured (usually blue) shade band at the top, to reduce the glare of winter sun. This is made by colouring the inter-layer of polyvinyl butyral plastic, sandwiched between the two glass layers of the windscreen. Until the mid-1990s, shadebands on North American windscreens, were always made by using a pigmented dye, which was almost transparent to the infra-red light used by the Rain Tracker™. Hence on older vehicles, mounting the Rain Tracker sensor behind the shadeband, presents no problems.

From the mid-1990s, most American cars were fitted with windscreens featuring a pigmented shadeband; the main reason for which, is that the pigmented shadeband, is more resistant to fading, than the earlier dyed shadeband. Unfortunately, the new pigmented shadeband blocks almost all infrared, so the Rain Tracker™ rain sensor cannot see through them. Hence, on most newer American cars, the Rain Tracker™ rain sensor will not function, when mounted fully within the shadeband region, but the infra-red emitters have enough reserve power to enable it to be mounted on the very edge of the shadeband.

If one has a car, van or light truck, with what appears to be a faded shadeband, one may mount the Rain Tracker™ rain sensor within it, but if the shadeband appears to be reasonably dark, then it would be wise to mount the Rain Tracker™ rain sensor on the "fade-out region" or below. Some non-US vehicles, and some aftermarket (replacement) glass is still made using dyed, infra-red-transparent shadeband material, but if one is in any doubt, then the Rain Tracker™ rain sensor, should be mounted below the shadeband.

http://www.raintracker.com/Compatibility/Shadebands-RT-50.htm 

The large single-piece windscreens, of some large RVs (i.e. Recreation Vehicles), may be thicker than ¼ inch, which is too thick for the Rain Tracker™. If there is a centre post or mullion in the windscreen, then it is probably compatible with the Rain Tracker™. RVs based upon truck chassis (class C motorhomes) have compatible windscreens.

Although the Rain Tracker™ rain sensor, is compatible with the common type of electrically-heated windscreen, having a multi-filament-wire conductor mesh, there is a rare type of thin-film, electrically-heated windscreen, similar to those used on some aircraft, which are wholly incompatible with the rain sensor. Whether this rare type, is used on any vehicles, in Great Britain or Europe, is presently unknown.

Mr. Rein Teder, founder & president of OEDES, is the author of 20 US patents, many of which are licensed by manufacturers of rain-sensors for new cars. He started Opto-Electronic Design to bring the rain-sensing, windscreen-wiper technology, to the aftermarket and speciality markets, having previously been instrumental in the development of the TRW factory-fitted system, now found on cars built in North America and Asia, which account for approximately 40% of World-wide market share.

Development of an after-market Rain Tracker™, rain-sensing, automatic wiper-speed controller, commenced in circa April 1998 and first appeared on sale, in the USA & Canada, sometime in 2000. This pioneering product, won the 2001, SEMA (i.e. Specialty Equipment Manufacturers Association) Best New Accessory Product award. The RT-50 model, is the first Rain Tracker™ that is universal in application and is priced at less than half of earlier models.

This product is presently available to individual customers, by direct purchase via the Internet, from OEDES, in Minnesota; costing US$149•00 (about £78•40 at recent official Bank of England exchange rates, of circa US$1•90 per £1•00 Sterling), plus shipping & import duty, for direct Internet purchases. I anticipate that it and other OEDES products, might soon become available in the United Kingdom, through various VW parts suppliers, plus general car accessory shops and mail-order companies.

USEFUL ADDRESS

Opto-Electronic Design Inc., 6440 Flying Cloud Drive, Suite 207, Eden Prairie, Minnesota, MN 55344, USA.
Tel. (International) +1 952 943 2378
Fax. (International) +1 952 943 1020
e­mail: info@raintracker.com
http://www.raintracker.com 

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