The shape alone makes your project difficult. You say touchscreens are everywhere, but have you ever seen one with non-convex shape?

Bob

 

There are plenty of companies that sell touch panels made of indium-tin oxide (ITO) that is vapor deposited onto glass or PET film then etched to your desired pattern or standard patterns. Most companies selling etched ITO panels that you can optically bond to a waterproof surface (glass, polycarbonate or acrylic) also have ready-made libraries available. The days of going it alone and developing code completely on your own from scratch for each project are long gone.

 

The important thing here is to get something like what you want, but that already works, and they go from there.

 

I have found a company that makes custom trackpads out of projected capacity : https://www.azoteq.com/
I have contacted them, they actually answered and asked me to provide them information about the project. At the same time I ordered every component necessary for my prototype, including a basic trackpad system from this company. I should receive everything in the next fex days/weeks (considering it's send from USA and I'm in France). I hope that I found a solution. I keep this thread opened to give the advancement on it and if this solutions actually works. Thank you all for your help.

 

Does s trackpad give you location? I think not, but thst is just s guess, that it operates like a mouse, giving inky deltas.

Bob

 

The Koala pad gave what amounted to XY locations on the pad. I believe others also do so but by using X-Y grids. The Koala pad used a resistive film with voltage across it in one axis then the other. Each time voltage was placed across the film, the pressure of a finger would cause the film to make contact with a backing conductor, thus forming the equivalent of a pot. The wiper when voltage was placed across the X axis was proportional to the X position, and Y worked similarly.

 

Projected capacitance (most capacitive touch) are scanned by a multiplexed array in x and y to measure capacitance change or a voltage (I2c or spi chips dedicated to this can also be pinged) to get exact locations - it is not like a mouse. Imagine your iPad or phone. The cursor goes where you touch, it does not go to some relative position (unless you are scrolling and that is calculated based on two exact locations over a known time delta). There is nothing about relative positioning like a mouse. All touch locations are known exactly.

 

@MrSalts,

You are talking about a touch screen, not a trackpad. A trackpad is the little rectangle below the screen on many laptops that acts like a mouse.

Edited to add: In case you missed it, TS mentioned ordering a trackpad for his prototype.

Bob

 

@MrSalts,

You are talking about a touch screen, not a trackpad. A trackpad is the little rectangle below the screen on many laptops that acts like a mouse.

Edited to add: In case you missed it, TS mentioned ordering a trackpad for his prototype.

Bob

The two work similarly, it's in the software if you want to flick swipe your cursor to move left snd right - the track pad is just calculating how much movement your finger made from a given point vs the position 0.1 seconds previous. The pad can sense exactly where on the pad your finger is located. The mouse control panel is simply trying to make the trackpad act as a mouse with relative positioning since the pad is so small vs the size of the screen.

 

Hi everyone,
Thank you for your answers. I see you are trying to figure whether or not a trackpad is suitable for my project. As I saw in their datasheets it seems like the technology used in their trackpad is the same (PCP) as in touch screens so I think that there shouldn't be any problems there. And even if it was working like a mouse, I think that wouldn't be a problem I could find a software based solution. In fact, all the system will be embded, not connected to a computer whatsoever so I should just find out a code to translate "mouse movement" into something I can use.
Anyway, I sent them all the information I gave you so they will be able to tell me if it is suitable or not. In the same time I ordered everything I need ( I think) and I'll receive it on Tuesday.

I have a question tho, I thought about it this morning, for the prototype I'm using a dev kit for the ESP32. That means I have power delivered by the USB then "translated" to the power need of the ESP by the dev kit board. but in the final product I'll have a custom PCB and the system will be powered by the classic 220V 1Amp of the house. I don't think the system will like this, How do I transform this current into the one I need for the system (much lower). Thank you!

 

Hi everyone,
Thank you for your answers. I see you are trying to figure whether or not a trackpad is suitable for my project. As I saw in their datasheets it seems like the technology used in their trackpad is the same (PCP) as in touch screens so I think that there shouldn't be any problems there. And even if it was working like a mouse, I think that wouldn't be a problem I could find a software based solution. In fact, all the system will be embded, not connected to a computer whatsoever so I should just find out a code to translate "mouse movement" into something I can use.
Anyway, I sent them all the information I gave you so they will be able to tell me if it is suitable or not. In the same time I ordered everything I need ( I think) and I'll receive it on Tuesday.

I have a question tho, I thought about it this morning, for the prototype I'm using a dev kit for the ESP32. That means I have power delivered by the USB then "translated" to the power need of the ESP by the dev kit board. but in the final product I'll have a custom PCB and the system will be powered by the classic 220V 1Amp of the house. I don't think the system will like this, How do I transform this current into the one I need for the system (much lower). Thank you!

You will either have to use an appropriate “wall wart” or “desktop supply” that provides the expected voltage(s) at sufficient current or include some sort of SMPS supply on your PCB. I would strongly suggest the former rather than the latter.

Supplies are readily available and a barrel jack will probably allow you to find one already terminated for you to use. Note that you may find it necessary to include one or more voltage regulators and/or boost or buck converters on your PCB depending on the voltage(s) you end up needing.

[EDIT: added regulator, boost, buck information]

 

The power supply can easily be handled by an on-board 230VAC to 3.3v (1 amp) component that is soldered directly to your board. Super easy but can get a bit dangerous having 230v traces on your PCB so review some safety guidelines for "hot" markings to warn anyone servicing the device that the board has mains power in certain regions.
https://www.digikey.com/en/products/detail/cui-inc/PSK-S5B-3/9817108