General design

The transmitter houses:

• the pressure sensing element

• the radio frequency transmitter

• flashing LED

• the battery

• the tire pressure equalizing automatic shut off valve (in dual units)

 

Sensing Element

One of the particularly unique features of the TyreAid is its sensing element. The sensing element is a pressure chamber filled with the exact same air pressure as the tire (often directly from the tire upon initial installation). One wall of this pressure chamber is made of a pressure sensitive membrane which flexes if the pressure inside the chamber exceeds the tire pressure by 0.6 bar (9 psi). This little flex makes electrical contact and the transmitter and LED become activated.  We do not warn for over pressure since that is a normal occurrence when the tires warm up. The important features from this design are:

• No use of the batteries when the tire pressure is within specifications. Since the batteries are totally disconnected from the unit until the tire pressure drops below the trigger point, the battery life equals the shelf life of the batteries. We are using a lithium battery with an extremely long shelf life of minimum 10 years.  Once the tire is underinflated and the transmitter and LED are activated, the battery will last a minimum of 2 months. Once the pressure is returned to specifications, the flashing stops and the battery is once again disconnected.

• Automatic ambient temperature compensation. Since we are measuring the tire pressure with an air pressure chamber, both the tire pressure and the chamber pressure will be equally affected by the ambient temperature.  Our sensing element is actually measuring the pressure differential between these two chambers, which will remain the same even during a cold morning. This avoids many false alarms.

• Customer can set or re-set trigger points.  With the proper pressure in the tire, just by the twist of the nylon lens, the trigger point is set or re-set.

 

Radio frequency transmitter

• Our transmitter is using a frequency of 434.1 MHz  

• Like all Radio Frequency devices, the transmitting range varies based on several factors. However, the standard range is between 200ft-300ft (60m - 90m)

• We are using 1 million distinctive codes to be able to "pair" the transmitter with selected receivers  

• Even if the transmitter is paired with certain receivers, any non-paired receiver will read every transmitter within transmitting range

 

Flashing LED

• We have designed our transmitter to have a flashing red LED to indicate an underinflated tire.

• We are using a super bright LED so it can be seen even in bright daylight.

• To minimize the power consumption of the bright LED we have a custom-made chip which allows the LED to flash 1/100 of a second every 2 seconds.

• Since each tire has a flashing LED there is no need to have a large display receiver in the cab with a detailed map of the vehicle tires to indicate which tire is low.

• This also avoids complicated programming between the transmitter and the receiver, since the exact location of the transmitters does not need to be programmed into the receiver. On other devices, this tedious programming needs to be redone after rotating and swapping tires and rims.

• This also allows the receiver to interact with any transmitter, so if you have multiple trailers combined with the tractors everything still works right out of the box with no programming needed.

• This allows a maintenance worker to walk by the fleet with a receiver in his pocket and then easily locate the flashing, underinflated tire once he has received a warning from the receiver. The receiver even has a signal strength indicator to show the distance to the troubled tire.

 

Battery

• We are using a commonly available Lithium battery, number CR-2.

• It is used in camera flashes and its chemistry and technology is very suitable for quick power bursts to accommodate the flashing LED and the Radio Frequency sending.

• It can be purchased from us, online, or from most battery suppliers/camera stores.

• The battery can be changed with the unit in place and the hoses connected. To change the battery only takes about 30 seconds

• The transmitter sends a signal to the receiver in case of a low battery. The low battery warning begins when about 33% of the battery life is left

• The maintenance worker can check the batteries by just pressing the test button. If battery is low, the LED has a rapid flash and sends a signal to the receiver (in his pocket) which then displays "Bat Trans"

 

Pressure-equalizing Automatic Shut-off Valve

• An often underestimated importance is the necessity to always have the same tire pressure in the dual wheels. Any pressure increase or decrease slightly changes the diameter of the tire. Since the dual wheels are bolted together without differential (like the rear axle has built in), maintaining equal pressure is absolutely essential to avoiding tire wear and added rolling resistance.

• A small 5 psi (0.35 bar) difference between two 36” wheels will make one tire 5/16” (8 mm) larger than the other

• This 5 psi difference will cause the larger wheel to drag the smaller wheel 13 feet for every mile driven, resulting in significant tire wear and added rolling resistance

• This 0.35 bar difference will cause the larger wheel to drag the smaller wheel 2.5 meters for every 1 km driven, resulting in significant tire wear and added rolling resistance

• Constantly open equalizing. Even if the tire pressure would be perfect at the beginning of the trip, after a relatively short distance, the pressures are already different. The inner wheel is close to the heat of the brakes while the outer wheel gets a nice cooling breeze and a pressure difference of 5-10 psi (0.3-0.7 bar) is quickly built up. This is why the constantly open equalizing is the only way to assure that this hazard will not occur.

• Automatic shut off. The equalizing is great unless you have one tire with a failure. Having both tires underinflated will cause a big problem. Our fully automatic equalizing valve can be set to any pressure and it will immediately fully close if one tire becomes underinflated, regardless if the under inflation is caused by a slow or rapid leak. We generally recommend having the equalizing stop at no more than 4 psi below the recommended tire pressure.

 

Location

The transmitter is mounted at the wheel hub or at the end of the axle, with a hose going to the valve stem(s). The reasons for this design are:

• Instead of using the wheel bolts we are using the hub/axle bolts to ensure that we are not compromising the design and integrity of the wheel mount. Every year we hear of accidents related to a wheel coming off the vehicle. These are often fatal accidents and we did not want our product to potentially be considered as a contributing factor to such accidents.

• The transmitter stays in place when the tires are being repaired or changed. Unlike most other TPMS which need to be removed from the wheel/tire and reprogrammed to another wheel. Our feature of keeping the device stationary on the wheel makes the job much easier for vehicle and tire maintenance.

• Since the location of the transmitter is near or in the center of the wheel, the weight of the unit will not have an impact on balancing. This has allowed us to make a very robust unit and we did not have to compromise quality for weight.

• An additional benefit with the center location is that we have been able to move the air filling and pressure check nipples to an easy-to-see, very convenient location. This makes filing the tires and checking the pressure easy for the tire maintenance personnel.

 

Features

• The transmitter is designed with a 10 year life expectancy. We give it a 5 year unlimited mileage warranty.  

• Hard anodized Aluminum body with Nylon lenses. These materials are used to ensure that the transmitter can survive any harsh conditions and chemicals the environment will expose it to.

• All electrical contact surfaces are either silver or gold plated. This ensures that even high moisture content in the tires will not disrupt the functionality of the transmitter

• Totally self-contained, no electrical wiring required. This makes installation easy. In fact our transmitter has such a strong signal that it will not need any signal repeater installed even if 2 trailers are connected to the tow vehicle.

• Effortless calibration of low pressure trigger point or preset at factory. We supply the transmitters either non-calibrated for the customer to set the trigger point or preset at the factory to the customers’ requested specifications. If factory preset, the customer can still change the trigger point at any point they wish. Changing the trigger point is done in only a few seconds

• Fits any pressure range from 3-12 bar (44-175 psi)

• Starts to flash and sends a radio signal when pressure falls 0.6 bar (9 psi). This sensitivity level can be adjusted higher or lower to meet the customer's demands, but this is our standard and most popular setting.

• Monitors pressure every second, 24 hours a day, 7 days a week, all without using the battery. The battery engages only if the pressure is below the threshold

• No need to have electrical power turned on in the vehicle. When maintenance personnel wants to remotely check the tire pressure, it can be done without turning on the power in the vehicle. This also allows the maintenance personnel to check parked trailers

• Programming. The TyreAid needs no programming. It works right out of the box. However, the receiver can be programmed to exclude other vehicles. This programming is done by simply flipping a switch on the receiver to activate programming mode, and then by pushing the test button on each wheel. The programming is now done and does not need to be re-programmed after wheel or tire changes. This programming can also be conveniently changed any time. For more information, look under the "receiver" section.

• Easy-to-use external test button to check functionality and battery condition. Push the button and you will see the unit flash once per 2 seconds. If the LED flashes more quickly instead, the battery is below half its power