Tilt Switches For Automated Responses To Changes In Angle
Tilt switches are electrical components that connect or disconnect circuits in response to a change of state. Tilt switches in particular are used to respond to changes in an object’s angle. This means that when an object is tipped or tilted past a certain preset, the switch will be activated and an automated response can be triggered.
These devices are incorporated into many different types of systems where an activation or shutdown must occur due to an abrupt or excessive change in orientation. This functionality can be applied to many different applications, including roll-over sensing and safety systems, fall alarms, safe-arming and detonation mechanisms, emergency shutdowns on various appliances.
Just a few examples of tilt switch applications are on munitions, automobiles, household heating and electrical cooking devices, safe-handling and training equipment, and even anti-handling systems, such as those incorporated into vending machines.
Tilt switches are known by a number of different names, including mercury switches, mercury displacement switches, ball switches, and tip-over switches. These names have varied based on the components and configuration of the switch but they usually refer to the same overall type of device.
Although designs of tilt switches will vary, at their most basic, they consist of leads or electrodes and a conductive element, also called a connector. These parts are contained in a sealed housing, also known as a can.
The switch’s connector is meant to move freely within the can. Depending on the position or placement of the switch, the normal state of the connector may be away from the leads, which amounts to an open circuit. Tilt switches may also be normally-closed. This means that the switch’s normal state will be configured so that the connector maintains a closed circuit.
Whether normally-open or normally-closed, the switch’s state will be disrupted by a change in its orientation. This can be set to a specific angle, which is determined by the switch’s configuration, or can be modified, as in the case of adjustable tilt switches.
Once the orientation of the switch exceeds the triggering angle, the connector will either part from or connect with the leads, thereby interrupting or connecting the circuit, respectively. Depending on which occurs, a system will then be activated or shut down.
When a tilt switch is used to detect a roll-over incident, for example, its connector will roll into the leads and trigger an alert, emergency mechanism, or other automated response. Conversely, a tilt switch used as a safety element on an appliance like a clothes iron or space heater, will be configured so the connector rolls away from the leads and the power is cut in order to prevent fires, burning, and other hazards.
Tilt switches are almost always non-latching. This means that the switch will return to its normal state once the object is returned to its standard position. This may or may not disrupt the response, whether that is an alarm, emergency shutdown, or other action, but this will depend on other factors incorporated into the system.
To ensure optimal functionality in critical and non-critical settings, all connective components of the switch must be made from non-eroding, highly conductive materials. Additionally, all housing must be properly sealed to prevent interference due to debris, moisture, and other factors. Since tilt switches must respond to changes in angle, the conductor is almost always a rolling element that will freely slide within the switch’s can.
In the past, a small quantity of mercury was predominantly used as the conductor between the switch’s leads. This element was favorable partly due to its low cost and high conductivity. This is why tilt switches are sometimes called mercury switches or are otherwise specified as mercury-free tilt switches.
Due to the now well-established hazards of heavy metals like mercury, tilt switches are mostly made from alternative materials. Mercury-free tilt switches have replaced mercury as the conductor and will instead use a ball bearing, electrolyte liquid, or other low-friction conductive elements.
The switch’s leads must also be highly conductive and resistant to corrosion. They are frequently made from materials like nickel and plated with gold or silver to maximize conductivity.
Tilt switch housing and cans may be made from a range of materials. Those used in critical capacities or in settings that are likely to be exposed to extreme temperatures, potentially corrosive conditions are hermetically sealed. This is a standard for tilt switches used in aerospace and military placements.
Though relatively simple sensor and automation devices in their standard form, custom tilt switches can be specially configured for unique applications and made from a broad range of materials and components.
A tilt switch manufacturer will be most capable of designing, developing, and manufacturing tilt switches that meet with custom or high-demand requirements.