Mealtime Partners, Inc.

Everyone interacts with switches throughout the day. We turn lights on and off, turn on the coffee pot; turn the TV on or off, etc. Every electronic device has some kind of switch. For people who have disabilities, accessing those switches can be a daunting, or impossible task. “Adaptive” switches are a means for people to be able to interact with devices without having to physically operate the switches on the device. More general information about adaptive switches can be found in Mealtime Partners March 2011 Newsletter. Activating adaptive switches can be accomplished using a wide variety of body parts. This article will address activating adaptive switches using feet, or a single foot.

Some individuals who use adaptive switches to access assistive technology (AT), activate the switches using their feet because, either, their feet are the most functional part of their body, or the only part of their body that is relatively easy to control. Regardless of why switches are being operated by use of a foot (or both feet), there are some very specific considerations in selecting the specific switches that will be used, and in how the switches are mounted. This article will be directed towards switches that can be used to control the Mealtime Partner Dining System; however, the logic used is appropriate for other AT as well. The items that should be taken into consideration are:

1. Does the individual wear shoes? When operating adaptive switches there is a significant difference in how aware you are as to the switch and whether you are triggering it when using your bare foot, your foot in a sock or your foot in a shoe.

2. Is the individual ambulatory or non-ambulatory? For people who are ambulatory (able to walk more than just a few steps) the choice of the type of adaptive switch that they will use is almost always a matter of personal preference. They will usually be able to activate a wide variety of different switches with their feet.

3. Does the individual sit in a regular dining chair to eat? If the individual sits at the table on a regular dining chair to eat their meals, the adaptive switch (or switches) can be put on the floor under the table. The majority of switches that are placed under a table for use do not require any type of mounting. However, if two switches are being used, it is easier to mount them on a plastic sheet to keep them reliably positioned relative to each other. When they are not mounted on a sheet they can move more easily which makes accessing them inconsistent. Additionally, when they are mounted on a sheet, they can be picked up easily and stored between meals.

4. If the user sits in a wheelchair to eat, is it powered or manual? There is a significant difference in selecting and mounting adaptive switches if the user is seated in a manual wheelchair or in a powered wheelchair. For those individuals who sit in a manual wheelchair to eat meals, whether the arm rests of the chair will fit under the table surface is a major consideration. If they do fit under the table, the person will be able to eat from the table without having equipment extended out from the table to enable them to reach the spoon. If they sit and eat off of the table, their foot placement at mealtimes should be addressed. Does the wheelchair have foot plates on which the person rests their feet? If the answer is no, the adaptive switches can be placed on the floor as described in 2, above. When foot rests are used the same issues that are described in 4 and 5 below (foot plates on a powered wheelchair) should be taken into consideration.

5. If they sit in a powered wheelchair to eat, what drive control is used to operate the chair? There are many different commonly used methods of controlling a powered wheelchair including using your head to drive the chair through controls mounted in a head array; using a mini-joystick mounted for control by the chin, lips or mouth; a hand operated joystick, or a foot controlled joystick. (The Mealtime Partners October 2013 Newsletter has detailed information about head control.) There are also other, less common, controls available. For most control systems the mode of operation of the chair is displayed on a small screen that is mounted in front of one of the arm rests. The mode can be changed by switch activation. For example, the chair can be in forward drive mode and can be changed to recline mode when the user needs this function. However, the display often can limit how close to a table top a user can position the wheelchair because it sticks up above the level of the arm rest so that the user can view it easily. With this restriction, equipment that is being accessed must be mounted so that it can cantilever out from the table towards the user to enable them to reach it comfortably. Regardless of the type of drive controls on the wheelchair, if adaptive switches are to be used via foot activation, the switches must be mounted on the wheelchair foot plate/s. If two adaptive switches are to be used, one operated by each foot, then a single switch should be mounted on each foot plate. If one foot is going to operate both switches, the foot plate and an appropriate mounting bracket for the two switches must be designed.

6. If a foot operated drive control is used, can the individual move their foot left and right when not driving the wheelchair? If a user is able to move their foot left and right, they will most likely be able to use the toe area of their foot (even when wearing shoes) to activate switches. The picture below shows a single Mini Cup Switch on the toe bracket of a wheelchair foot control. A second Mini Cup Switch could be added to the other side of the bracket. To activate either switch, the foot would need to pivot slightly at the heel enabling the right or left side of the toe to make contact and activate the switch. The switches are very light touch requiring only a small amount of force and movement (1/10^th inch depression) to activate them.

Mini Cup Switch on Toe Bracket of Permobil Wheelchair Foot Control

If the individual is able to comfortably produce more foot movement than described above, a switch could be mounted on the toe bracket and a second on the heel bracket. The foot would then need to rest in the middle of the foot plate to avoid accidental switch activation.

7. How much force or pressure is the individual able to produce using their foot or feet? Many individuals are able to produce considerable force with their foot or feet without exerting much effort. However, if only a small amount of force is easy to produce, light touch switches are advisable. There are several different momentary switches commercially available that would meet the needs of someone who can only produce a small amount of force with their foot: the Mini Cup Switch, the Spec Switch, the Micro Lever Switch, and the Micro Light Switch all require relatively little force for activation.

8. Are they able to produce fine movement with their feet or are they only able to make gross movements? For some people making small movements in a controlled manner is difficult. It is easier for them to produce a large, or gross, movement. For people who find it easier to produce large foot movements for switch activation, there are a variety of heavy duty adaptive switches that are designed for foot control that can withstand significant force. They are designed to be pushed by the foot using larger muscles in the foot, ankle and/or leg. Examples of these switches are: Pal Pad switches that come in 3 different sizes; the Square Pad switch; or one of the several Ability switches.

Ability Fist, Foot, or Wheelchair-Bump Switch (typically operated by foot)

Ability switches, like the one pictured above, come in a variety of resistance levels. In other words, the amount of pressure or force needed to close (i.e., activate) the switch varies among types of switches. Inside the switch is a spring that holds the switch open and must be compressed to close the switch. The stronger the spring, the harder the switch will be to close. Some switches have a spring strong enough that you can rest your foot on the switch without triggering it. This allows the user to keep their foot in the same position even when they are not activating the switch.

When purchasing foot switches, note that they do not all come with a standard phono jack connector necessary to operate the Mealtime Partner Dining Device. Some have USB connectors, and others have a two-prong or three prong plug for connecting to power outlets. The Mealtime Partner requires a switch with normally open contacts that has a standard (3.5 mm) stereo phono plug that is provided on most popular Adaptive Switches. If there is a question about whether a switch can be used with the Mealtime Partner Dining Device, please call us for technical support, or let us provide it for you with your order of a Dining System to ensure compatibility.