go_away

Author Topic: Sharp GP2Y3A001K0F Multi-Beam Ranging Sensor (I tested it)  (Read 1810 times)

0 Members and 1 Guest are viewing this topic.

Offline AdminTopic starter

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,632
  • Helpful? 169
    • Society of Robots
Sharp GP2Y3A001K0F Multi-Beam Ranging Sensor (I tested it)
« on: July 16, 2010, 03:04:04 PM »
I just finished testing the Sharp GP2Y3A001K0F Multi-Beam Ranging Sensor. If you don't already know, its 5 Sharp IR units in one single super unit.

The datasheet was seriously lacking, so I did some experiments to characterize it. Hopefully this data is useful for someone . . .

current requirements:
There are two power lines, one for digital circuitry, and one to power the LED.

The LED output line requires 0.190mA (yeap, incredibly low!). This is stable, and can be powered right off a mcu digital output pin no problem.

The digital circuitry power line requires ~20mA average, but fluctuates quite a lot at high frequency. I suspect its electrically noisy like the other Sharp IR units, and probably needs a ceramic cap across it and ground to improve the power draw stability . . . I didn't further test this theory.


accuracy:
If the object is within 25cm, this sensor is accurate within ~1cm. If the detected object exceeds this distance, the sensor will acknowledge that further distance in its measurements. However, this output is both unstable and unreliable by a large percent, and becomes more inaccurate as the object distance increases.

Offline Soeren

  • Supreme Robot
  • *****
  • Posts: 4,672
  • Helpful? 227
  • Mind Reading: 0.0
Re: Sharp GP2Y3A001K0F Multi-Beam Ranging Sensor (I tested it)
« Reply #1 on: July 19, 2010, 06:36:01 PM »
Hi,

current requirements:
There are two power lines, one for digital circuitry, and one to power the LED.
I believe pin 9 is just for powering the oscillator - the power to be fed from Vcc (pin 8 )


The LED output line requires 0.190mA (yeap, incredibly low!). This is stable, and can be powered right off a mcu digital output pin no problem.
I guess you mean LED input, as outputs aren't spec'd for their current demand ;)
Pin 9 is turning the oscillator on (probably a gate or similar) and pins 1 to 5 are selecting the active LED(s) via transistors, so they only need a modest base current.
It would have a range of 1cm or likely less, if the LEDs only had 190A to live on


The digital circuitry power line requires ~20mA average, but fluctuates quite a lot at high frequency. I suspect its electrically noisy like the other Sharp IR units, and probably needs a ceramic cap across it and ground to improve the power draw stability . . . I didn't further test this theory.
I think the LED current draw is showing up here as the main component - is it more or less consistent with the oscillator frequency (with a bit from the digital circuitry and a pinch of noise)?
Regards,
Sren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline AdminTopic starter

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,632
  • Helpful? 169
    • Society of Robots
Re: Sharp GP2Y3A001K0F Multi-Beam Ranging Sensor (I tested it)
« Reply #2 on: July 20, 2010, 06:56:03 AM »
current requirements:
There are two power lines, one for digital circuitry, and one to power the LED.
I believe pin 9 is just for powering the oscillator - the power to be fed from Vcc (pin 8 )
hmmmm looking closer at the Block diagram it is definitely not clear which power source powers it . . . but given the incredibly small current drain, I pretty sure you're right.

Quote
The LED output line requires 0.190mA (yeap, incredibly low!). This is stable, and can be powered right off a mcu digital output pin no problem.
I guess you mean LED input, as outputs aren't spec'd for their current demand ;)
oops, typo! :-[

Quote
The digital circuitry power line requires ~20mA average, but fluctuates quite a lot at high frequency. I suspect its electrically noisy like the other Sharp IR units, and probably needs a ceramic cap across it and ground to improve the power draw stability . . . I didn't further test this theory.
I think the LED current draw is showing up here as the main component - is it more or less consistent with the oscillator frequency (with a bit from the digital circuitry and a pinch of noise)?
I didn't scope this sensor because of laziness. But with the other Sharp IR sensors, yes, it is consistent with the oscillator frequency.

 


Get Your Ad Here