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| Brymen IR connection protocol - Anyone sniffed it yet? |
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| t1d:
Wow, Serggio, that's real good looking work. Thank you for offering to allow us to use it. I have already developed a DMM to Laptop PIC18F4550 converter platform. I use it for lots of different projects. I just need to plug all the components together and I am ready to go. Tell me about your SMD components, particularly about the IR LED and Phototransistor. If I could find those two components, with their connector pads on the top surfaces, so I can invert them on my board, I would reconfigure the board, for people that want to use SMDs, too. I would like that type of IR interface, for myself. We need the light bandwidth to be 880nm, with I am working on a Homemade Reflow Oven, with my brother. All of the hardware has been developed. All that is left is for my brother to finish the code work. |
| serggio:
Hi t1d. I did a lot testing with different IR diodes. I will help you later. Sorry, i'm not front of PC. What information you want to know? I using Vishay 5mm leds, photocurrents from 3 mm really weak and required preamplifier for good signal. 880 and 940 really doesn't matter ;) ?????????? ? ????? iPhone ????????? Tapatalk |
| t1d:
Something odd happened when making this post... Here is the complete reply... Wow, Serggio, that's real good looking work. Thank you for offering to allow us to use it. I have already developed a DMM to Laptop PIC18F4550 converter platform. I use it for lots of different projects. I just need to plug all the components together and I am ready to go. Tell me about your SMD components, particularly about the IR LED and Phototransistor. If I could find those two components, with their connector pads on the top surfaces, so I can invert them on my board, I would design a second version of my board, for people that want to use SMDs, too. I would like that type of IR interface, for myself. We need the light bandwidth to be 880nm, with a low power requirement that can be driven directly off of the PIC 18F4550 pin. I am working on a Homemade Reflow Oven, with my brother. All of the hardware has been developed. All that is left is for my brother to finish the code work. An SMD version of this board would make a great first-run project. |
| t1d:
--- Quote from: serggio on May 14, 2016, 01:06:57 pm ---Hi t1d. I did a lot testing with different IR diodes. I will help you later. Sorry, i'm not front of PC. What information you want to know? I using Vishay 5mm leds, photocurrents from 3 mm really weak and required preamplifier for good signal. 880 and 940 really doesn't matter ;) ?????????? ? ????? iPhone ????????? Tapatalk --- End quote --- Yes, I need to go, myself... I look forward to talking with you, later... |
| serggio:
--- Quote from: t1d on May 14, 2016, 01:11:59 pm ---Yes, I need to go, myself... I look forward to talking with you, later... --- End quote --- Ok.. This is just part of my uncompleted AN that I preparing for future posting, but some information can help you... --- Quote ---....Now we will need to connect our UART lines from our FT232R (Tx and Rx – only two needed) to our measuring device MCU thru optoisolated infrared line. For that we’ll need emitting and receiving photodiodes working in infrared specter. Usually this is 870-950 nm wavelength but most common infrared photodiodes able to receive signal in this diapason close to their peak wavelength characteristic. You can use 870, 880, 890, 900, 940, 950 nm emitting and receiving diodes. Only one thing need to remember… If you build interface for 115 200 bps connection speed, you need to be careful in choosing diodes. The main characteristic is are Rise/Fall time. We need depend “bit length” time – time in which emitting diode must be active or receiving photodiode must able to recognize signal. For 115 200 bps one bit have 6,8 uS length and out emitting diode must be able to switch On and Off as fast as possible to provide square form pulse for receivers. So device with 600-800 nS rise and fall time acceptable, 15 nS preferred. That rule also common for receiving photodiode and best devices have 5 - 2,5 nS rise/fall time duration. We absolutely not able to use phototransistors for high connection speed, while they provide much bigger photocurrent to compare with photodiodes, their turn on/off time is 2-3 uS and short bits will not be recognized by them. Photodiodes instead – our best friend here, but they provide very small current in chain and we’ll need additional parts of equipment to connect it to our FT232R in order to data received by photodiodes will be transformed to TTL or CMOS levels. --- End quote --- As for photodiode, I suggest you use leaded components instead SMD. For example BPV10(NF) http://www.vishay.com/photo-detectors/leaded-devices/ Because of emitting diode in meters driving with small current for power saving, you need to most sensitive photodiode to have enough amplitude (over 1V) on resistor connected in series with your diode. SMD photodiodes with 50-60 uA output photocurrent will be big in size. http://www.vishay.com/photo-detectors/list/product-81128/ In my board RX and TX LEDs this is just green and red emmiting LEDs for information purpose only. They can be excluded. D1 and Q1 - this is diodes for interface. Hope this will help you. |
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