Sound-activated circuit wirelessly turning another one on
Dakk
Posts: 4
Hey there. I aspire to create a little device for reasons unspecified that would work as such:
One circuit is sound-activated. This would preferrably be powered by a battery or two (the other circuit as well) and it would active when it hears a sound "loud as hell", such as it is right next to someone screaming or an alarm of some sort. Do i measure this in the sound intensity (dB) or should i measure it in some other unit? I would like this circuit to send a wireless signal that would turn another circuit on. How would i go about to do this?
I've completed the first year of electrical engineering so even thouh i have all the basics and such, i still have no idea where to start.
One circuit is sound-activated. This would preferrably be powered by a battery or two (the other circuit as well) and it would active when it hears a sound "loud as hell", such as it is right next to someone screaming or an alarm of some sort. Do i measure this in the sound intensity (dB) or should i measure it in some other unit? I would like this circuit to send a wireless signal that would turn another circuit on. How would i go about to do this?
I've completed the first year of electrical engineering so even thouh i have all the basics and such, i still have no idea where to start.
Comments
The link is a sound sensor. This could easily connect to the Propeller. There are a number of very simple ways to transmit wirelessly to some other device. Xbee, Nordic, etc. First get a Prop board of some sort, then get the sensor. An LCD display like the Parallax 2x16 or a TV output would be nice to see the output. Once you can see the sound values displayed, then move the next step of transmitting it.
https://www.parallax.com/product/29132
I think I have three of these devices. I just use one sensor and set all three chimes to the same channel. This way I can be pretty much anywhere in the house with the radio blaring and or water running and still hear the doorbell. It make quite a racket when a little neighbor kid rings the doorbell a dozen times in a row.
It's a shame things haven't changed in 35 years. My EE girlfriend back in college couldn't actually build a simple circuit in her junior year. Stay tuned to this forum and get yourself a "What's a Microcontroller" package to work through this summer as do your own projects. You'll learn more practical stuff there and here than in 4 years of school.
I feel like i in theory know alot, but i simply don't know the approach or the workflow as to creating your own circuit. Where would i even start? Could you or someone else here maybe outline a workflow as to creating a circuit to order parts to
Getting started with a project requires a lot of non-electronic background knowledge (suppliers, available chips, circuit boards, cases, etc.) that takes time to accumulate. Take erco's advice, get some learning kit from Parallax, and ask for help and advice on the forum. After a couple of completed projects you will have acquired a lot of valuable knowledge and experience.
Otherwise my process for a new PCB is:
1 Put ideas into a block diagram.
2 Look for off the shelf solutions instead of a new design. (You can use the building blocks suggested thus far).
3 In a new design try to determine the IC parts, connectors, cables, power supply requirements, size, enclosure, heat dissipation, total cost, component cost, required reliability, accuracy, maintenance, and the development and assembly time.
4 Identify the most difficult problems to solve and figure out where the risk factors are. Always have a plan B for any unknowns.
5 Concept-Plan peer review.
6 Schematic entry. For each part in the schematic have a pdf datasheet in the design folder. Keep a spreadsheet of the parts used by your own PN, cost, manf PN and vendor PN. The schematic entry tool should be able to generate a BOM.
7 Next PCB layout and order parts. Digikey.com is my favorite place to find the correct parts using their parametric search engine.
8 Be sure to match physical parts with layout footprints.
9 Generate Gerber files for PCB manufacture. In a readme.txt file spec thickness, layers, finishes, silkscreen, HASL/ENIG etc., pitch, impedance-traces and spaces, hole count, ROHS or leaded---
10 Make PCB boards
11 Solder on parts and you're done.
A new design is not a cake walk. You have to have the CAD tools (Diptrace), a little pocket change and time, about 4 -6 weeks start to finish or longer for a newbie.
Or you can "You can use the building blocks suggested thus far." Start anywhere and things will magically fall into place.
That sounds like a fun project! It sounds like it'd be a good idea to have one side have a microcontroller monitor a sound sensor (much as the other folks have linked). And when it picks up a signal from the sound sensor, it can send a signal through say an xbee or some other wireless transmitter.
Then on the other end, you could have a microcontroller constantly checking for a signal from the transmitter, and when it senses it, it could cause your receiving circuit to turn on (maybe through a HIGH/ON from a microcontroller pin).
My steps on how to approach this:
1) Figure out how to get the microcontroller to work with the sound sensor. Have the serial terminal tell you when it hears a sound.2) Figure out how to get the microcontroller to work with the xbee/wireless transmitter. So that when you press a button, it sends a note to the receiving end - this will require 2 MCUs and 2 xbees in total.3) Figure out how to activate the xbee when your sound sensor is triggered.4) Figure out how your receiving end talks to say a serial terminal when it receives a message from the transmitting xbee5) Figure out how your receiving end can trigger your end/secondary circuit to turn on.6) Finally, figure out how the signal from the xbee can trigger something to turn your secondary circuit on.
Once you have these components together, you should have a functional circuit that does what you asked for.
Let's say you absolutely do need a Propeller (great choice), then you'd want to see what all a propeller needs to function. It needs a good power source, it needs memory, it needs circuit protection (decoupling capacitors). Then you start figuring out how they'll connect together. In the beginning, I'd do pictures first, then convert them to schematic symbols - mostly because I wasn't comfortable with them.
Example:Step 1:
Step 2:
Step 3: http://tymkrs.tumblr.com/post/20065099953/schematic-draft-2-heart-led-project
My engineering friends eyes bled, but by jove, I learned from this process! If you're already comfortable with the schematic symbols, then decide what you need for the MCU to run, for the XBEE to run, all of that. Essentially, take out of the prototyping stage, what you actually need for the manufacturing stage. Isolate that stuff out.
Then use a pcb design program (KiCad, Eagle, Diptrace) - learn how to make schematics with that. There are tons of tutorials out there for each of these programs to show you how to make the appropriate schematic symbols and part modules. It'll just take time. But that's okay!