 | | Shutting off illumination LED on Light Sensor for LIDAR
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Has anyone successfully found a way (short of paint, or cutting internal wiring) of shutting off the red 'supply light' LED on the Lego light sensor? The supply LED is great for active-detection situations, like line-following, when you need to (...) (24 years ago, 28-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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This sounds very cool. If you want to do the mapping at the bottom, you will have to use alternitive firmware anyway (right?), and they have a passivate command that turns off the light. It passivates the sensor, but I don't think standard firmware (...) (24 years ago, 28-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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(...) Maybe. I think RCX2 with NQC has some crude arrays, I haven't looked into them yet, but I might be able to use them to do simple mapping on the RCX. Or something even cruder if I don't have arrays. (...) Ahh. Hmm. I wonder what it actually (...) (24 years ago, 28-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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Hi Chris, You can turn off the LED with software though you may be a little disappointed with the light sensitivity. The reason the LED is on is because your program has set the sensor to an active sensor. If you set the type to NONE make the mode (...) (24 years ago, 28-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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To make a passive light sensor, you can use a design like Michael Gasperi's: (URL) costs only a couple bucks, and works quite well. If you would like better response from your lego light sensor, you can use a piece of black shrinkwrap tubing and (...) (24 years ago, 28-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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Ralph Hempel had an example of the heat-shrink tubing solution here: (URL) also tried used some black vinyl from a binder? -Tim (...) (24 years ago, 28-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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(...) You can find light sensor schematics on Michael Gasperi's page: (URL) Using the RCX IR emitter as the illumination source. Don't know (...) Someone has already tried this. You can check Simen Svale Skogsrud's page for an example, with NQC (...) (24 years ago, 28-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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As an alternative method to tubing, you can use an IR filter (black inversible film) as described on my page : (URL) doesn't work with Lego visible lamp though... Philo (URL) (24 years ago, 29-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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I drilled a hole in a 1x2 brick to give the light sensor a better sense of direction and to block the LED. The goal was to have the light sensor seek an IR beacon. (...) (24 years ago, 29-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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(...) Thanks for all the tips, everybody. I set out last night to open up my light sensor and add a jumper to allow me to take the LED out of the circuit. I was unsuccessful in getting the casing open, even after cutting the underside latching tabs (...) (24 years ago, 29-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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(...) That's not a legOS feature. You just set the input port to passive mode, and read it in RAW mode. There is an example in NQC at (URL) (I forgot to add the address in my previous post :-). (...) You can find light sensor schematics on Michael (...) (24 years ago, 29-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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(...) Thanks. I had seen this technique (and noticed this effect myself) but had heard rumor that this impaired the sensitivity of the detector. I'm going to try some rigorous tests and see if I can verify this. (...) We almost needa Yahoo-style (...) (24 years ago, 30-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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(...) I strongly suspect this is a myth. A transistor is a transistor is a transistor. They all require biasing in order to function properly and that requires power. Mind you, even so-called passive devices must either generate a voltage or have a (...) (24 years ago, 31-Mar-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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(...) Actually you don't need LegOS, any input set to raw mode with the LEGO firmware will do fine. This is because even in passive mode there is a pull up of 10k to 5V, and in fact the LED is glowing dimly in this mode. Just tried it, I can get raw (...) (24 years ago, 1-Apr-01, to lugnet.robotics)
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| | Re: Shutting off illumination LED on Light Sensor for LIDAR
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(...) Yes, this is the result I discovered this weekend. My conclusion is that setting the sensor to raw mode does not fully remove the light produced by the LED, and detrimentally impacts the sensor performance. I think my next approach is to try (...) (24 years ago, 2-Apr-01, to lugnet.robotics)
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