I would need a little assistance to help a disable friend with a DIY foot mouse

Hi guy's,

First my name is Peter and i have a friend who lost both his arms in an accident and he was enjoying gaming before and i want to help him to get back in something he use to like to do as a hobby.

I have already done a lot of reading on what was available for this and nothing was really answering his need or it was far too expansive since he only get social assistance and barely make it from months to months.

I have no prior experience in electronics but i am a techsavy type of guy's and a 18 years 3D artist in the game industry and i learn pretty quick. I already know the basic for the type of project but need some advice and a little help to make for him the best DIY foot controller.

What i am building is based on this instructables here : https://www.instructables.com/foot-operated-computer-mouse/
But i want to do a few modifications that will make it better for a gamer since this project was more for a casual user browsing the net and doing little computer use.

First the guy in the instructable use roller switch and i don't think this kind of switch would be the best choice for foot operations left/right clicking intensively in a game environement, so i made a small research and found this arcade button switch here : https://shop.xgaming.com/products/20-pack-arcade-buttons-no-switches

Also i would like to ad to his foot controller another button for DPI changing but i am not sure about how to solder the wire to this Kailh SMT Mini Micro-switch
and also not sure about the type of switch that would work for that type of function ,here a view of this switch in the mouse i bought for him, you can go to 3:24 to see the type of switch :
For the left/right click buttons i just need to know which wire i need to solder on the arcade switch to the mouse clicking omron switch to make it work in parallel?

Now for this i am not so sure how to tackle the hardest part i mean a controller that could trigger the wsad movement possibly on the same foot board and i already have an idea on the layout for this but struggle to find the type of switch or joystick that could be easily manipulate with foot.

What would be ideal is somekind of multi directional rocker switch position in a cross layout like arrow keys on a keyboard. He tried with voice control but he cannot stop easy with voice command or move slowly in a control manner.

Any suggestions are welcome to make this foot controller a reality. Thank in advance for any help you can provide

Regards Peter

Peter
The best option in my opinion would be to use a hemisphere with his foot on the flat circle and the ball allowed to move on a plate with a circular cup in the plate with a radius slightly larger than the hemisphere. That's the input motion. The sensor for the motion should be an accelerometer/gyroscope chip connected to a microcontroller. The accelerometer can sense the position for wasd. If you add a foot strap, he will likely have enough leverage to trigger with his toe on the same foot. Switches used for gaming can quickly exceed maximum lifetime actuations and be worn i out. The non-contact actuation of an accelerometer eliminates mechanical switching and will never wear out. The toe switch/trigger should be a good quality gaming switch like you show.

gophert said:

Peter
The best option in my opinion would be to use a hemisphere with his foot on the flat circle and the ball allowed to move on a plate with a circular cup in the plate with a radius slightly larger than the hemisphere. That's the input motion. The sensor for the motion should be an accelerometer/gyroscope chip connected to a microcontroller. The accelerometer can sense the position for wasd. If you add a foot strap, he will likely have enough leverage to trigger with his toe on the same foot. Switches used for gaming can quickly exceed maximum lifetime actuations and be worn i out. The non-contact actuation of an accelerometer eliminates mechanical switching and will never wear out. The toe switch/trigger should be a good quality gaming switch like you show.

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Hi Gophert and thank for the suggestion, i already thought about this one since there is a controller call 3D rudder that seem to do something similar but the main issue i can see is the wide motion require by the ankle to activate the sensor and this wide movement will probably make it very difficult to push the left/right click button.

I remember seeing a few years ago a video of a guy who made the kind of rocker switch i was having in mind but the video is nowhere to be found after an extensive search i made. If i could find a way to make a mechanism that would be sitting under the left foot with a limited movement that could lean on front, back,left,right on a contact point that would trigger the wasd. For this to work the mouse base would need to be separated since the left foot would be on a 2 layers mechanism, top would be mobile(limited)and buttons for left/right click and bottom would be the mechanism so this way the foot would have a better stability to push the various buttons. This is just a very rough idea and i will make a 3D model to show what i am having in mind.

How about two huge foot operated trackballs. Something based on: https://en.wikipedia.org/wiki/Trackball

One foot would have 2 mouse buttons and the other 2 ounse buttons. The trackballs - either work.

Big and giant - that's the problem.

I would like to help with this project and look forward to seeing how you progress. Can you describe the movement available?

Mike.

Check out this post on Hack-A-Day where a guy made a giant track ball by putting a micro and sensors INSIDE the ball. There might be some useful ideas for this application.

After thinking about the mechanics a bit more, an accelerator-like pedal with a loop on the pedal. The pedal in a neutral foot position so they can press forward (w) and tilt back (s). Then add a foot box on top of the pedal that is only connected to the pedal at the heel as a pivot. This way, the user can make medial and lateral rotations of the angle to operate the a & d key movements (as the box swings to hit buttons mounted on the wide pedal. Note that switches (buttons) should be very close to the neutral position of the pedal and the rotating foot box to minimize dead time between movements (make the device more responsive).

Visitor said:

Check out this post on Hack-A-Day where a guy made a giant track ball by putting a micro and sensors INSIDE the ball. There might be some useful ideas for this application.

Giant DIY Mouse Sets The Ball Free

Make the move to a split keyboard and the first thing you’ll notice is that you have all this real estate between the two halves. (Well, as long as you’re doing it right). This is the p…

hackaday.com

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Thank for posting this since it is bringing new idea in my head and it look interesting.

Pommie said:

I would like to help with this project and look forward to seeing how you progress. Can you describe the movement available?

Mike.

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Thank Mike all the help i can get will benefit my friend and also others with disability. If you refer to the first post there is an instructable link that i am using as a base but since then many new ideas came to my mind and i am drawing this in 3d so people could have a better understanding on the type of mechanism i want to implement.

KeepItSimpleStupid said:

How about two huge foot operated trackballs. Something based on: https://en.wikipedia.org/wiki/Trackball

One foot would have 2 mouse buttons and the other 2 ounse buttons. The trackballs - either work.

Big and giant - that's the problem.

Click to expand...

I thought about trackball since i already own one and i can see more fatigue from using it instead of an inverted mouse where he would just have to gently swipe a kung fu type of slipper with a glued mouse pad fabric on the sole over the optic of the mouse. Also the mouse i am using is a 8000 dpi optical sensor from logitech so he could quickly change dpi on the fly from another arcade button on the board.

A guy on youtube made something similar here :

gophert said:

After thinking about the mechanics a bit more, an accelerator-like pedal with a loop on the pedal. The pedal in a neutral foot position so they can press forward (w) and tilt back (s). Then add a foot box on top of the pedal that is only connected to the pedal at the heel as a pivot. This way, the user can make medial and lateral rotations of the angle to operate the a & d key movements (as the box swings to hit buttons mounted on the wide pedal. Note that switches (buttons) should be very close to the neutral position of the pedal and the rotating foot box to minimize dead time between movements (make the device more responsive).

Click to expand...

Seem like another good idea and tonight i am looking at all sort of pivot joint mechanisms to get the project into gear. I am trying my best to not make it over complicated since simple is always better and easier to maintain. My friend is reading the thread and he is very excited about the project and he want to thank everyone helping us with it.

Saw this video here about a student project, interesting but seem pretty clumsy.

More idea here but i am specially interested by the sensors use for this but adapted to the mouse board

More idea here that are interesting

This guy here made another one that is interesting but i find it way too complicated in my own opinion but it is good to see how other tackle such a project. Instead of the optical being project to the foam part i think that the more simple inverted mouse under the board is a better approach.

After a few days of thinking and seeing multiple projects and mechanisms i came up with 2 ideas and i have already made my choice on the second one since the simplicity and stability seem to be the better choice.

After reading a lot on accelerometer and gyro i decide to discard these solutions because the player would have no stability for the cursor since it's pretty hard not to move at all the pedal when the foot is on it. The solution is rather simple since to be able to play fps games he only need to have control of both the movement wasd and the position of the cursor + a few extra buttons like dpi, left/right click and even a jump button on the top center of the pedal. This way he can easily move and control player camera.

This one was the first concept but the ball joint made it very unstable to tilt even with springs for clicking the buttons and it require more work on the board that need to be fit so the pedal was on same height.



This concept is the one i think will be easier to build and would give optimal result since the foot pedal is mounted on teflon pads and stabilize with elastic bands to maintain it centered. The elastic bands need to have the correct tension factor so the pedal could glide to trigger the switches without too much effort and be hard enough to avoid accidental push on the pedal. I thought about springs but they often become looser after awhile and elastic bands are cheap and easy to replace.

Now i need to figure out how to connect all 4 cherry mx switches and the jump and maybe another optional button, so far from i have read i would need an arduino UNO for this work and it should be recognize as just another keyboard by windows but i am still not sure what would be the best way to do it so if you have the knowledge then feel free to share with us. Also critics are welcome since many heads are always better to get the best solution possible.

The Uno can't behave as a keyboard of mouse. You need a Leonardo or any board with a 32U4 processor, See here. I've been playing around with these weighing devices and thought 4 arranged in the four directions might give good results.

Mike.

Pommie said:

The Uno can't behave as a keyboard of mouse. You need a Leonardo or any board with a 32U4 processor, See here. I've been playing around with these weighing devices and thought 4 arranged in the four directions might give good results.

Mike.

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Thank Mike for the tips and link but i don't understand the weight sensors, how do they work exactly?

The weight sensors will each measure up to 5kg - so 20kg total. They will bend (very) slightly when a load is detected. They can be set to zero at any point so your friend could place his foot on the board and the sensors could be zeroed. A push on the ball (of the foot) will see the front sensor increase and the back sensor decrease. Same for left/right. The Leonardo can read these sensors and move the mouse at a speed relative to the difference in pressure. It might even be possible to tap the plate to represent a mouse push.

As I had some of these sensors lying around (from an earlier project) I quickly knocked together this.


There is (of course) another wooden board which goes on top.
The two circuit boards are (dual) Analogue to Digital converters so the scales can be read.
I have a Leonardo handy so will attempt to write some code when I have time - probably at the weekend.
I'm hoping everything still works as two of the sensors are very corroded.
I'll let you know how it goes.

Mike.
BTW, Sensors and boards work out about US$5 a pair.

Anyone know of any reason why I can't use two sensors with one HX711 board? I've hooked the (excitation) supply to both sensors and wired the green and white wires to the two channels but nothing seems to be working. Probably a mistake between keyboard and screen and I'll double check tomorrow. Beer time now.

Mike.