ante Posted May 17, 2004 Report Posted May 17, 2004 Hi Ted,Interesting circuit this one. I have tried to analyse it but couldn Quote
Ted Posted June 8, 2004 Author Report Posted June 8, 2004 There shoud be someone out there who knows how the timebase are calculated . I urgently require these theory analysis for my project. Quote
MP Posted June 8, 2004 Report Posted June 8, 2004 Just a quick look, but it looks like two sets of 7404 setup as oscillators. One is flashing the laser diode and the other is "anded" with the return signal, then this is processed and a calculation is made of the difference.Not much, but hope it helps.MP Quote
ante Posted June 8, 2004 Report Posted June 8, 2004 MP,Thanks for your input I see what you mean. Could this be an accurate instrument do you think?Ante ::) Quote
Ted Posted June 9, 2004 Author Report Posted June 9, 2004 Thanks for your input, do you know of the formula to calculate the frequency , when using two not gates. Quote
MP Posted June 10, 2004 Report Posted June 10, 2004 ante,Radar is a bit out of my area of knowledge, but it seems like any reflection of the laser would cause you to lose accuracy when the signal bounces back. From the description in the project, it will only be accurate if you are directly in front of the object and it is moving toward you. Ted, I found an application note on oscillators here:http://www.fairchildsemi.com/an/AN/AN-118.pdfLots of info and the formula is also there. Hope it is helpful.MP Quote
Ted Posted June 10, 2004 Author Report Posted June 10, 2004 Thanks MP. It was very helpful.I can now move a step forward with my analysis.Do you happen to have a good source of info on D flip flops . I want to use one as a start and stop gate. Quote
MP Posted June 11, 2004 Report Posted June 11, 2004 Actually, I do. I have attached it in PDF format. Good luck with the project! Let us know how you did on it.MPflip_flops_and_momentaries.pdf Quote
ahmedlac Posted January 3, 2006 Report Posted January 3, 2006 Thanks for your input, do you know of the formula to calculate the frequency , when using two not gates. Quote
hazanohazizul Posted May 23, 2006 Report Posted May 23, 2006 hai.... can someone help me, i was during the digital radar speedometer project but i don't know what kind of Laser Diode and Laser LED that been used, can someone give me a part number PLEASE..... :) Quote
hazanohazizul Posted May 23, 2006 Report Posted May 23, 2006 Hi....Do you know what kind of Laser Diode and Laser LED that been used in this project....Can you give me the part number please..... Quote
audioguru Posted May 23, 2006 Report Posted May 23, 2006 The laser receiving diode is wired so that it is forward biased and is conducting all the time.I don't see how it can give an output. Quote
hazanohazizul Posted May 24, 2006 Report Posted May 24, 2006 laser diode it is not for transmitted but it for receiving a spot of light or a FC frequency Quote
audioguru Posted May 24, 2006 Report Posted May 24, 2006 laser diode it is not for transmitted but it for receiving a spot of light or a FC frequencyThere is no such thing as "a laser receiving diode". It is just an ordinary photodiode that is sensitive to visible light. Quote
MNA Posted May 24, 2006 Report Posted May 24, 2006 Then Audioguru, how can the crkt work..... Is there any way to make it work? Quote
audioguru Posted May 24, 2006 Report Posted May 24, 2006 I don't think that the circuit works with its photodiode backwards and without an amplifier. Quote
MNA Posted May 24, 2006 Report Posted May 24, 2006 So, can't it be corrected easily.....can 74LS be used instead of 74AS ? Quote
audioguru Posted May 24, 2006 Report Posted May 24, 2006 So, can't it be corrected easily?The entire circuit would need to be thoroughly analysed and maybe re-designed.can 74LS be used instead of 74AS?I guess you didn't compare the datasheets: The AS is 5 times to 9 times faster than the LS. Quote
MNA Posted May 25, 2006 Report Posted May 25, 2006 Anyone knows any other radar or lidar speedometer? I only found this one http://books.google.com/books?vid=ISBN0070112754&id=pv5F15t6B7QC&pg=PA528&lpg=PA527&printsec=8&dq=radar+gun+circuits&sig=RqFYZvotoF7AhPnG486L67pog3oRamsey SG7 is the same....parts searching is becoming a great problem for me..... Don't know if 1SS99 and NE021 are easily available......What will be the effect if 74AS is not used in the "Digital Radar Speedometer" ? Why this crkt has been left as it is ?Why not corrected?speedometer_ramsey.pdf Quote
MNA Posted May 25, 2006 Report Posted May 25, 2006 I don't think that the circuit works with its photodiode backwards and without an amplifier.http://books.google.com/books?vid=ISBN0070112762&id=e_X2-LqfKaMC&pg=PA293&lpg=PA292&printsec=8&vq=Laser+diode+transmitter&dq=encyclopedia+if+electronic&sig=QwOeQmUMtenfBl09pCiZSA3CXPglike this? Quote
audioguru Posted May 25, 2006 Report Posted May 25, 2006 Why not just attach the schematic here, instead of having everyone go over to Google and log in there to see it? I can't see the schematic in Google's Book Search! Quote
MNA Posted May 25, 2006 Report Posted May 25, 2006 Sorry,bu I'm unable to attach it....it is .html and can't get it into .jpgwill try again Quote
login
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.