IR Sensor Problems — fried?

[PuiChi]

[font=Verdana]For testing purposes, we hooked up 1 servo with 2 unshielded sensors, and they worked fine. When the beacon was on, the servo would stop, recieving IR; when the beacon was off, the servos would move in attempt to locate the beacon. [used tracker.zip]

However, after we shielded 4 sensors with shrink-wrap tubing, mounted them on 2 servos, and tried the sensors using the same code, the servos kept moving and sensors didn't see any IR, even when we stuck the sensor right infront of the sensor. We attempted using both PWM1 & PWM2 on the beacon, also all PWM-DIGI combinations on the servo and sensors.

Did we fry the sensors when we shrink-wrapped the tubing over the sensors, or is it something else? o____O;;

Please Help--!

[Mark McLeod]

Originally Posted by PuiChi

[font=Verdana]For testing purposes, we hooked up 1 servo with 2 unshielded sensors, and they worked fine. When the beacon was on, the servo would stop, recieving IR; when the beacon was off, the servos would move in attempt to locate the beacon. [used tracker.zip]

However, after we shielded 4 sensors with shrink-wrap tubing, mounted them on 2 servos, and tried the sensors using the same code, the servos kept moving and sensors didn't see any IR, even when we stuck the sensor right infront of the sensor. We attempted using both PWM1 & PWM2 on the beacon, also all PWM-DIGI combinations on the servo and sensors.

Did we fry the sensors when we shrink-wrapped the tubing over the sensors, or is it something else? o____O;;

Please Help--!

Could be...
You're sure the sensor leads aren't touching inside that heat shrink?

[Teh Kaj]

They can't, there is an individual heat shrink tube around each pwm wire.

[Mark McLeod]

Originally Posted by Teh Kaj

They can't, there is an individual heat shrink tube around each pwm wire.

We've been heat shrinking ours (we have a bunch for experimentation and spares) and haven't burned any out with the heat gun yet. We don't hold the heat on for very long. We sort of wave it over the heat shrink then off, then on, etc. to help the IC stay cool. I keep my hand close enough to the IC to make sure it's remaining cool.

The sensor wires could be switched on the interrupts and cause the same symptoms.
Are you displaying the status of tracker?

[Teh Kaj]

We didn't wave the heat gun on and off, we kept it on waving back and forth on the sensor. I seriously held it after for warmth cause it was cold.

Also we're not putting it on the EDUbot, we're putting it on the Robot Controller. We've checked and double and triple checked the inputs and still had no response of sight by the sensors. We watched the data and only got "still searching." When we unplugged and replugged the sensor pwm's we would get a response of it going left to right or sometimes the data flow would stop completely.

Our electrician didn't use a heatsink when soddering the wires so he may have fried them like that.

[Mark McLeod]

Originally Posted by Teh Kaj

Our electrician didn't use a heatsink when soddering the wires so he may have fried them like that.

Also make sure you use a low power soldering iron, like 15-20 watts.
Let us know what happens.
Good luck.