*Built a "laser tripwire", but it seemingly only functions nicely in a dark room and seems VERY susceptible to changes in ambient lighting. Is that simply how it is unless using a much more powerful laser? What about adding a visible light filter or something such as that?*
Congrats Karen, you implemented a cool idea with an analog circuit and avoided unnecessary mcus that are so easily over choosed today. I know how difficult video production could be, and despite some rough edges and "not as analog as it could be" (op amps, audio amp, better detection method, etc) it was quite good. Its been quite some time since an e14's video got my attention!
You could avoid long wires altogether if you just put everything in one box and use a mirror to bounce the laser back to the LDR. That makes placement much easier and more flexible.
Ok. Let's try. Bad idea is to use 2xne555 for sound. Motor from light can make disturbance and effect sound. Instead you can use car alarm siren for it. It's loud and less components on pcb. Everything else is ok. You can add wireless 433mhz receiver to reset alarm. So only you can reset it.
i love the way you teach i finally understand things. i wonder if you would make a light beam audio transmitter receiver? it can be done using a cheap flashlight or a laser. but i dont understand the receiver part very well and id like to make one for the kids and help them to become more interested in electronics also. could you make a set and show us how and include the part list and links to buy the parts please? thanks in advance i hope so much that you can find or make the time! you are doing so great keep it up!
Hi Karen, and happy new year! Maybe use a transistor or MOSFET to drive the speaker? I am surprised the 555 does not blow up, and that might explain the weird sound?
It's very possible. I got the circuit design from a 555 circuits ebook by Colin Mitchell. It's a "Police Siren." I tried it on the breadboard and it worked, so I didn't question it beyond that. [shrug] I will say the sound was fine on the breadboard. Nice and clear. It only got weird once it was all soldered together, so I'm guessing it was because of some weird crossed signals somewhere, or I messed something up in translation with my board layout.
@@maker_karen1785 Take out the board and retrace every connection, against the circuit diagram. Make sure every contact is like in the schematic. Then with a sharp knife make sure there are no wild connections between close enough pads on the board. Some stranded solder spikes or bridge.
I wish to have a 12V supply as I want to activate a 12v solenoid or actuator. Can I use the same components you have in your Diag or would I need to supplement? Any help would be appreciated...
so instead of alarm you wire a relay to it then then the relay opens the circuit to either your higher power battery or a buck converter buck converter is usually good
Pin 7 of the 555 to vcc? That sounds ... strange. Pin 7 is "discharge" and is an open collector to gnd, it would create a short whenever pin 6 "threshold" is held high.
For the weird noise, I think - I have not tested it yet - that using pin 5 ("voltage control") to turn the second chip on or off does not quite achieve the job - if you want to have a on-off tone, you can get the output of the bistable to the reset on the first 555 and the output of this 555 to the reset of the second (the one driving the speaker). Using pin 5, you can actually create a two-tone alarm: the bistable then drives the reset on both 555, and the output of the first 555 drive the VC (pin 5) of the second 555. The resistor between the two should be tweaked to achieve the right voltage change. Internally, there is a voltage divider with 3 5k resistors (www.ti.com/lit/ds/symlink/lm555.pdf). Voltage Control (pin 5) arrives directly between the first and second resistors and at the junction with the threshold comparator. With your 10k resistor, trigger and threshold are set to 38% and 75% of Vcc when high, and 22% and 44% when low: when high, the frequency is significantly lower than when low. I will play with this when I get a chance.
Unfortunately we have to put the playlist in backwards order so that the most recent episodes show up on our channel page. However you can find a list that is in order as well as all the resources for the episodes on the element14 community - www.element14.com/thelearningcircuit
Could you do a musical hallway some time? It would be along the lines of this circuit. Something where a photo-transistor on 1 side of a hallway and a bright led on the other side of the hall could cause musical tones to play as someone walked thru the different transistor/led pairs for 8-10 feet maybe spaced out a foot apart. Like musical stairways but more basic. The demo could be small in size for the video to make it less troublesome. I think some people call these air harps. Thanks!
We made a laser harp back on The Ben Heck Show. Though it was mostly all Ben and Felix that built it. I remember it being kind of a nightmare for them.
It's a Weller WT1. I really like it. It heats up very fast, is easy to adjust the temperature, and keeps a very consistent temperature. Would recommend.
SORRY I CANNOT SEE VERY WELL. HENCE ALL CAPS. CAN I USE A BOARD WITH WIFI? I was told 8266 has WiFi. I NEVER PUT CODE IN BEFORE. I NEED STORAGE BUILDING / WORKSHOP INBACK YARD PROTECTED. WIFI / I CAN SEND TO COMPUTER . I WILL START USING HOME ASSISTANT SOON HOPEFULLY. VERY COLD IN WINTER AND HOT IN SUMMER, NOT GOID FOR RASPBERRY PI TO WORK. IF YOU KNOW HOW, A DOOR / WINDOW SENSOR WOULD WORK. I THINK SOME USE 8266 FOR THAT ALSO. I DONT KNOW BATTERY REQUIREMENTS. SINGLE LION MAYBE OR IT MAY HAVE CORD TO RUN...PLUG IN..? Please advise. Most Humble Appreciation! Alton
We need to have a warning saying WARNING Class III LASER in use to protect premises, We need a an op-amp driving a series pass transistor to control the current and voltage to the laser and also a small resistor connects from the negative side of the laser diode to negative and a 47K resistor from the junction of the laser diode and the resistor to ground feeds back to the inverting pin on the op-amp as we don't want to burn out the LASER diodes as they are expensive.
Real laser tripwires send a modulated binary signal that's a value generated by an algorithm to prevent you just shining another laser in the hole, or doing a replay attack...
Nice catch, guys. Yup, I definitely shouldn't have connected pin 7 on the 1st 555 timer to Vcc. That's a big error! Yup. Don't do that. Haha
*Built a "laser tripwire", but it seemingly only functions nicely in a dark room and seems VERY susceptible to changes in ambient lighting. Is that simply how it is unless using a much more powerful laser? What about adding a visible light filter or something such as that?*
Congrats Karen, you implemented a cool idea with an analog circuit and avoided unnecessary mcus that are so easily over choosed today. I know how difficult video production could be, and despite some rough edges and "not as analog as it could be" (op amps, audio amp, better detection method, etc) it was quite good. Its been quite some time since an e14's video got my attention!
You could avoid long wires altogether if you just put everything in one box and use a mirror to bounce the laser back to the LDR. That makes placement much easier and more flexible.
Oh that's a really good idea!
Ok. Let's try. Bad idea is to use 2xne555 for sound. Motor from light can make disturbance and effect sound. Instead you can use car alarm siren for it. It's loud and less components on pcb. Everything else is ok. You can add wireless 433mhz receiver to reset alarm. So only you can reset it.
i love the way you teach i finally understand things. i wonder if you would make a light beam audio transmitter receiver? it can be done using a cheap flashlight or a laser. but i dont understand the receiver part very well and id like to make one for the kids and help them to become more interested in electronics also. could you make a set and show us how and include the part list and links to buy the parts please? thanks in advance i hope so much that you can find or make the time! you are doing so great keep it up!
Neat project! Thanks, Karen!
Hi Karen, and happy new year!
Maybe use a transistor or MOSFET to drive the speaker? I am surprised the 555 does not blow up, and that might explain the weird sound?
It's very possible. I got the circuit design from a 555 circuits ebook by Colin Mitchell. It's a "Police Siren." I tried it on the breadboard and it worked, so I didn't question it beyond that. [shrug] I will say the sound was fine on the breadboard. Nice and clear. It only got weird once it was all soldered together, so I'm guessing it was because of some weird crossed signals somewhere, or I messed something up in translation with my board layout.
@@maker_karen1785 Take out the board and retrace every connection, against the circuit diagram. Make sure every contact is like in the schematic. Then with a sharp knife make sure there are no wild connections between close enough pads on the board. Some stranded solder spikes or bridge.
Why connect pin 7 of the first 555 to Vcc? Why do you need to short Vcc to ground when the output goes high?
Ok you got my interest with this one
I wish to have a 12V supply as I want to activate a 12v solenoid or actuator. Can I use the same components you have in your Diag or would I need to supplement? Any help would be appreciated...
run it to a relay
so instead of alarm you wire a relay to it then then the relay opens the circuit to either your higher power battery or a buck converter buck converter is usually good
Pin 7 of the 555 to vcc? That sounds ... strange.
Pin 7 is "discharge" and is an open collector to gnd, it would create a short whenever pin 6 "threshold" is held high.
For the weird noise, I think - I have not tested it yet - that using pin 5 ("voltage control") to turn the second chip on or off does not quite achieve the job - if you want to have a on-off tone, you can get the output of the bistable to the reset on the first 555 and the output of this 555 to the reset of the second (the one driving the speaker). Using pin 5, you can actually create a two-tone alarm: the bistable then drives the reset on both 555, and the output of the first 555 drive the VC (pin 5) of the second 555. The resistor between the two should be tweaked to achieve the right voltage change.
Internally, there is a voltage divider with 3 5k resistors (www.ti.com/lit/ds/symlink/lm555.pdf). Voltage Control (pin 5) arrives directly between the first and second resistors and at the junction with the threshold comparator. With your 10k resistor, trigger and threshold are set to 38% and 75% of Vcc when high, and 22% and 44% when low: when high, the frequency is significantly lower than when low.
I will play with this when I get a chance.
Yup, you have to bind the reset pins from both 555 to the output of the bistable if you want to create a two-tone siren using pin 5.
Your "The Learning Circuit" Playlist is completely in the wrong order with somehow your team adding new videos to the top of the playlist.
Unfortunately we have to put the playlist in backwards order so that the most recent episodes show up on our channel page. However you can find a list that is in order as well as all the resources for the episodes on the element14 community - www.element14.com/thelearningcircuit
Could you do a musical hallway some time? It would be along the lines of this circuit. Something where a photo-transistor on 1 side of a hallway and a bright led on the other side of the hall could cause musical tones to play as someone walked thru the different transistor/led pairs for 8-10 feet maybe spaced out a foot apart. Like musical stairways but more basic. The demo could be small in size for the video to make it less troublesome. I think some people call these air harps. Thanks!
We made a laser harp back on The Ben Heck Show. Though it was mostly all Ben and Felix that built it. I remember it being kind of a nightmare for them.
What do you do to avoid oxydation of the PCB?
Since I just build these for these videos, I don't really do anything about it because I don't need them to last long.
Dear I just wanted to know which solder iron do u use
It's a Weller WT1. I really like it. It heats up very fast, is easy to adjust the temperature, and keeps a very consistent temperature. Would recommend.
Thanks dear ,but I'm from India ,I don't think it will be available here
Hi Karen happy new year
When will you make another video? We have a longing for your videos.
here we go again.. everytime i suddenly wanted to do a project like this one there's always one component that i dont have. this time its LDR😤😭
that's the fun part improvising and breaking shit it how u learn
SORRY I CANNOT SEE VERY WELL. HENCE ALL CAPS. CAN I USE A BOARD WITH WIFI? I was told 8266 has WiFi. I NEVER PUT CODE IN BEFORE.
I NEED STORAGE BUILDING / WORKSHOP INBACK YARD PROTECTED. WIFI / I CAN SEND TO COMPUTER . I WILL START USING HOME ASSISTANT SOON HOPEFULLY. VERY COLD IN WINTER AND HOT IN SUMMER, NOT GOID FOR RASPBERRY PI TO WORK.
IF YOU KNOW HOW, A DOOR / WINDOW SENSOR WOULD WORK. I THINK SOME USE 8266 FOR THAT ALSO. I DONT KNOW BATTERY REQUIREMENTS. SINGLE LION MAYBE OR IT MAY HAVE CORD TO RUN...PLUG IN..?
Please advise.
Most Humble Appreciation! Alton
We need to have a warning saying WARNING Class III LASER in use to protect premises, We need a an op-amp driving a series pass transistor to control the current and voltage to the laser and also a small resistor connects from the negative side of the laser diode to negative and a 47K resistor from the junction of the laser diode and the resistor to ground feeds back to the inverting pin on the op-amp as we don't want to burn out the LASER diodes as they are expensive.
✅🟢
Real laser tripwires send a modulated binary signal that's a value generated by an algorithm to prevent you just shining another laser in the hole, or doing a replay attack...
Make it lauder to annoy intruders
WEEOOWEEOOWEEOOWEEOO
@@maker_karen1785 thats the way🙂
This is the way.
Too much info
Thats not how you make a sandwich.