Foot Pressure Sensor

Projects General Guidance
1

FPC - 20 Pins
FPC - 20 Pins1848×1444 209 KB

Marked
Marked1872×3507 473 KB

Guys, I have this problem. I think I could map the lines right (Check out the images), and yet I still can't get accurate values. I'm using a ESP32 and I'm only testing 1 sensor, let's say the number 2. It's linked to the ESP32 GPIO36 VP-Pin, as the simple code below shows.

The first VCC line is wired to the 3v3 pin. I wonder if I have to connect something to GND? I tried it already, but I got no Values. When I disconnect the GND from the GPIO36 VP-Pin I got some values but it's not constante. Sometimes it stuck at the maximum value: 4095.

const int sensorPin = 36; // (GPIO36 VP Pin)

void setup() {
  Serial.begin(115200); 
}

void loop() {
  int sensorValue = analogRead(sensorPin); 
  Serial.print("Sensor Value: ");
  Serial.println(sensorValue); 
  delay(1000); 
}
2

Our problem is different. We have no clue about what you are using or how you have it all wired up and how you have it all powered. A drawing of how all is connected as well as data sheet links to the actual devices you are connecting would immediately help solve our problem.

2 Likes
3

You have not enabled the pin. Start at the basic blink sketch and progress from there.

4

The soldering shown in the first picture needs to be improved.

Adafruit and Sparkfun have good tutorials, with lots of photos of correct and problematic connections.

5

I uploaded 2 Images. But I'm going to upload the whole thing in the next comment.

But I'm pretty sure the lines I drew are correct. I suppose there are 2 power lines connecting half of the sensors. They are lines 7 and 14.

Lines 1 to 6, 8 to 13, and 15 to 18 are the pressure sensors.

So, I wired sensor 2 to ESP32 pin 36, and the line 7 to 3v3. (Check out the image,there is a FPC 20-Pin connector).

6

Why not just upload a link to the technical specifications of what that thing is in the images?

1 Like
7

Yes.  Many of the pins appear to have no, or very poor connections to the pads, just a blob of solder on the protruding pin.  Add flux to everything and resolder.  Verify continuity with a multimeter.

8

The thing is: I am just trying the first 2. And yes, it needs to be improved. Continuity test is ok, everything is connected. Still the same errors / not working. Thanks, guys.

9

No, your connections are the problem. Every solder joint is a cold joint (wire was not at temperature and did not receive the solder, so the solder balled up and sits on top of the pin). When you "test" the joints, the pressure you apply causes continuity.

11

I see.. I will attempt to solder it again. As you can see, it is not my specialty, but I will try to improve it. Thank for the advice.

12
  • Use a lot of FLUX on the solder joints.
  • Ensure your solder iron is around 350C to 380C.
  • Hold the hot iron against the PIN and PAD until the FLUX is boiling (three seconds?)
  • Hold the solder against the PIN/PAD/IRON until the solder "wicks" onto PIN/PAD/IRON
  • Remove solder
  • Remove iron

You should see the solder in the form of a capital "A" on and around the pin.

o8dbvwmg5t771
o8dbvwmg5t771729×431 62.4 KB

3 Likes
13

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