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Topic: I am seeking a Arduino programmer for my project (Read 57 times) previous topic - next topic


Someone can make a device like the following details? If YES how much it costs a prototype?

Device  based on capacitive technology. The new device includes a USB port for connection to personal computers implementing a HID interface that can connect transparently to operating systems Windows,  and also includes a new Serial port to communicate with devices with RS232 input.

When the device is connected to a computer, this emulates a standard USB keyboard, which means  can send alphanumeric characters to
any application on the computer.

The device has a RS-232 communications port.

The alphanumeric characters corresponding to each sensor input are sent through the RS-232

The default setting for the RS-232 port is: 9600b, 8, N, 1.


Device  has 16 inputs for sensors named 0 to F, which are the characters that are
transmitted by default.

The sensors may be installed on a non-conductive  smooth surface.

The detection method is based in the capacitive technology of each sensor, so that when a finger is approaching, the sensor produces a variation, which is detected by the Device and sends the corresponding code to the computer.

Power : USB - 5 Vdc, 80 mA (0.4W)

USB Communications
Number : 1
Connection : Connector USB Tipe-B
Interface : HID Keyboard + HID Custom

RS232 Communications
Number : 1
Connection : Connector RJ12

Capacitive Sensors Input
Number : 16

Levels : 10
Kind : Rotary selector / Software

Auxiliary Digital Input
Number : 1
Kind : voltage free contact.
NPN transistor output of PIR sensor





Hi Luigi,

Are you looking for a programmer, or for someone to make one of these devices for you?
There are 10 types of people in the world, those who understand binary, and those that don't.


are you ready to make it happen?




Hi patduino,

I'm waiting for your answer.




Hi Luigi,

I'm trying to determine the scope of the task.  What support are you looking for from the forum?
There are 10 types of people in the world, those who understand binary, and those that don't.



So you have a couple of things here. A touch-sensitive keypad, and keyboard emulation.

The sensors may be installed on a non-conductive  smooth surface.
If I were to do your project, I'd be looking at sending you a sheet of self-adhesive vinyl with cooking foil stuck to it for sensors and and a ribbon cable to go to the arduino. Is that what you had in mind?

There's a couple of sketches:

The difficulty is that you want 16 of these. There's going to have to be some hardware external to the arduino. It might be possible to do something with diodes: four pins to charge a row, and four pins to read how long the columns take to discharge, maybe. It might be possible to reduce the number of pins needed. Perhaps a latching shift register might do the job.

Actually, how about using a shift register (a pair of daisy-chained 8-bit registers) to select one of the pads to be 'charged', and cycle through them? Each pad drains through a resistor to ground, and also runs through a diode to a sensor point (which also has a resistor to ground). You'd move a bit through the register to charge up one selected pad, pause for a tick for everything to drain except for the pad you are testing, then clear the shift register and time how long it takes for the charge to disappear.

As for the keyboard side of things - multiple examples of that:


I suppose the main issue is that you want a physical prototype delivered. Not the same as just giving someone some code.

Looking further through your requirements, you state you want an rj12 connector. What's that going to do? I mean - we could glue one to the case, but if you want it to do anything you have to say what. And there's a PIR sensor. What do you want your sketch to do in respect of that?


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