Path: ...!eternal-september.org!feeder2.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Klaus Vestergaard Kragelund Newsgroups: sci.electronics.design Subject: Re: IR detector system, biasing of photo diode Date: Mon, 28 Oct 2024 11:11:38 +0100 Organization: A noiseless patient Spider Lines: 42 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Mon, 28 Oct 2024 11:11:38 +0100 (CET) Injection-Info: dont-email.me; posting-host="8eda3d0e7776cfa8c8ed473dd245a729"; logging-data="1005523"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19KNC6xc0Ibos7d2aXWjEE02MCToYZAfmY=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:F/qfJ2pUntIU05k7Qnb1Snws2Qc= In-Reply-To: Content-Language: en-US Bytes: 3014 On 27-10-2024 18:56, john larkin wrote: > On Sun, 27 Oct 2024 09:03:20 GMT, Jan Panteltje > wrote: > >> On a sunny day (Sun, 27 Oct 2024 02:19:14 +0200) it happened Klaus Vestergaard >> Kragelund wrote in : >> >>> Hi >>> >>> I am working on an IR detector that will guide a robot into a docking >>> station. >>> >>> A IR transmitter on the docking station transmits a beam, and 2 IR >>> detectors on the robot detects the beam and lets the robot navigate >>> towards the target. The working distance is a couple of meters. >>> >>> I need it to be insensitive to ambient light/sunlight. >> >> >> I use a cheap camera module to track a light source in H and V direction, and just a simple Microchip PIC : for processing >> It can, with some added code, track object forms too, like a cross or maybe a big character. >> panteltje.nl/pub/horizontal_IR_target_tracking_4686.avi >> those camara modulea are IR sensitive to some extend, sometimes you can remove the IR filter from such modules. >> It may be a bit of overkill for your application, but OTOH it can do a lot more. >> Mainly designed to detect and follow jet exhaust.. >> You could uee utrasonics too, maybe even simpler, no sun problem, like a bat. >> Cheap electret mikes? or modify some ebay 1 dolalr distance sensors... >> can be used for anti-collision too. >> >> > > Right. A sonic scheme could measure the phase between two mikes to > determine the direction of the source with high resolution. That could > be an analog multiplier or a bit of code. The amplitudes would be > useful too. > > One could compute direction, distance, and velocity almost for free. > > No problem with sunlight! > Could also be done with a chirp and auto-correlation, although this does not use the phase, but a beacon reference instead