2.7 KiB
title, date, categories, excerpt, header, gallery
| title | date | categories | excerpt | header | gallery | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MCS-12085 - Mouse Sensor | 2019-07-04 | cool-chips | A pretty cool sensor salvaged from a really old mouse. |
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Written 8-19-19
During one of my random thoughts, I had the idea of taking apart a mouse and reverse engineering its sensor for use with an Arduino. Rummaging through my dad’s old electronics, I found a PS2 mouse that I was pretty sure we would never use. First I used a PS2 library to communicate with the mouse and make sure it was still working. After that I took it apart to take a look at its sensor.
As it turns out, this mouse (I think it was a Dell) used a MCS-12085. It’s so old that I couldn’t find any major electronics distributors selling it. Surprisingly though, there are a bunch of articles online about this sensor. I proceeded to desolder this sensor and its associated components to put together my own board.
{% include gallery %}
While there were libraries available, the communication method shown in datasheet looked pretty simple so I decided it was the perfect exercise to do. I looked at code from this library for inspiration.
{% highlight C %} #define CLK_PIN 11 #define DAT_PIN 12
void setup() { Serial.begin(115200); mcs12085_init(); }
int x, y = 0; void loop() { x += mcs12085_dx(); y += mcs12085_dy(); Serial.print(x); Serial.print(" "); Serial.println(y); delay(5); }
void mcs12085_init() { pinMode(CLK_PIN, OUTPUT); pinMode(DAT_PIN, OUTPUT); digitalWrite(CLK_PIN, HIGH); digitalWrite(DAT_PIN, LOW); delay(100); //Power Supply Rise Time }
int8_t mcs12085_dx() { return mcs12085_read_register(0x03); }
int8_t mcs12085_dy() { return mcs12085_read_register(0x02); }
uint8_t mcs12085_read_register(uint8_t reg) { mcs12085_write_byte(reg); delayMicroseconds(100); return mcs12085_read_byte(); }
uint8_t mcs12085_read_byte() { pinMode(DAT_PIN, INPUT); uint8_t result = 0; for (int i = 0; i < 8; i++) { digitalWrite(CLK_PIN, LOW); digitalWrite(CLK_PIN, HIGH); result = result << 1 | digitalRead(DAT_PIN); } pinMode(DAT_PIN, OUTPUT); return result; }
void mcs12085_write_byte(uint8_t val) { for (int i = 0; i < 8; i++) { digitalWrite(CLK_PIN, LOW); digitalWrite(DAT_PIN, val & 1 << 7); //get msb val = val << 1; digitalWrite(CLK_PIN, HIGH); } } {% endhighlight %}
The sensor actually worked really well. I’ll probably use it for some kind of robot in the future but for now it’s nice to add another sensor to my repertoire.