I'd recommend using either the Teensy's or [URL="http://digistump.com/products/1"]digistump/digispark[/URL] to interface with the computer over USB. You could just do a bare bones development with any old AVR chip and use the V-USB library/driver, but that takes a bit more effort than the Teensy/Digistump route which has the USB stack presupported with stuff like HID, Serial-over-USB, etc.
I'm assuming when you mean key, do you mean detecting for a particular tone? Or just a normal switch.
Going the tone detect, you could use a tone detector IC like the [URL="http://www.ti.com/lit/ds/symlink/lm567c.pdf"]LM567[/URL] or [URL="https://www.rcscomponents.kiev.ua/datasheets/ba1604_datasheet.pdf"]BA1604[/URL], and possibly add on some digital potentiometer to change the detection frequency on the fly. Both output logic zero (requires a pull-up resistor) when the signal is detected.
Or with a normal switch just make a debouncer circuit and hook it up to the uController.
[QUOTE=andreblue;50023339]Maybe try a [url]https://www.pjrc.com/teensy/[/url] They can act as usb devices.[/QUOTE]
I built this using an old Teensy board that I had. It was going to end up in my center console for my CarPC, but I just ended up using up using a $5 IR steering wheel remote from eBay. Oh well, it was fun to build.
[t]http://i.imgur.com/HUENByD.jpg[/t]
[QUOTE=Falcqn;50023344]What's your setup with the USB soundcard? A little more info would be useful.
It sounds like you're thinking of putting a switch in series with an analogue audio line which is generally not great, since switches are very noisy and you don't want that getting into the signal, and any filtering would be awkward since you don't wanna touch the frequency content of your audio signal if possible.
[editline]29th March 2016[/editline]
There are plenty of microcontrollers on the market that support USB, so finding one of those shouldn't be an issue, PIC and AVR are pretty popular. If you're looking to send the audio signal over USB (still not sure what you mean by 'usb soundcard interface' - does it interface with a usb soundcard? or is it a usb device that handles audio?) you're gonna want to find a microcontroller that has a decent ADC, or find a separate ADC chip for audio stuff. 24 bits @ 44 to 48 KHz is pretty standard when it comes to digital audio.[/QUOTE]
Uh, yeah 24 bits is so unbelievably overkill. Assuming a 5 volt input range that gives you a 300 nanovolt resolution. You will never build an audio circuit where the noise floor is anywhere near that level. Even 16 bit is pretty overkill but some people [I]may[/I] be able to hear the difference at over 16 bits but it is unlikely.
At that level 24 bits doesn't even help mitigate the quantification error as the typical noise floor might be in the hundreds of micro volts range or low millivolts.
Edit: I mean if you want to be pedantic, 16 bits doesn't cover the "full" range of human hearing nor does 24 bit but that is misleading. The "full" range of human hearing exists from the absolute threshold of hearing at the low end to the pain threshold at the upper end. Unless you are listening to a system that goes from pin drop to standing next to a jet engine you do not need the "full" range of hearing. I don't have the link right now but ~-70dB seems to be the lowest possible distortion people can hear relative to a 0dB signal so any SNR higher than that is pretty much a wash.
[QUOTE=Falcqn;50023344]What's your setup with the USB soundcard? A little more info would be useful.
It sounds like you're thinking of putting a switch in series with an analogue audio line which is generally not great, since switches are very noisy and you don't want that getting into the signal, and any filtering would be awkward since you don't wanna touch the frequency content of your audio signal if possible.
[editline]29th March 2016[/editline]
There are plenty of microcontrollers on the market that support USB, so finding one of those shouldn't be an issue, PIC and AVR are pretty popular. If you're looking to send the audio signal over USB (still not sure what you mean by 'usb soundcard interface' - does it interface with a usb soundcard? or is it a usb device that handles audio?) you're gonna want to find a microcontroller that has a decent ADC, or find a separate ADC chip for audio stuff. 24 bits @ 44 to 48 KHz is pretty standard when it comes to digital audio.[/QUOTE]
[t]http://i.imgur.com/kwgDcuP.png[/t]
Orange lines imply what is effected.
Specifically I'm looking for [url=http://www.ebay.ca/itm/USB-2-0-3D-Sound-Card-Adapter-External-Virtual-7-1-Channel-Audio-PC-Laptop-Win7-/381069814012?hash=item58b987e8fc:g:Rw0AAOSwaNBUeD0o]something like this[/url] to directly interface with [url=http://www.ebay.ca/itm/Baofeng-Speaker-mic-UV-3R-Mark-II-UV-100-UV-200-BF-U3-BF-U8-hand-shoulder-radio-/131740848313?hash=item1eac5dd0b9:g:38cAAOSw4UtWSvk7]a microphone like this[/url]
I [I]could[/I] wire a TRRS adapter that goes to a normal SP/MIC TRS/TRS input and then a line to the GPIO of my computer, in this case a Raspberry Pi, but I'd like to make my own interface.
[URL="http://www.ti.com/product/PCM2912A"]Ti actually makes a dedicated USB soundcard chip.[/URL]
As for detecting PTT, you'd probably want to get a teensy or something else that can emulate a keyboard, and have the ptt ring of the trrs trigger that.
So I'm trying to get the hang of using this logic probe I have... I need to use the pulser to be able to detect a frequency is present in a project I'm working on, simple right? Testing on my arduino uno I have the probe hooked up to the arduinos ground pin and 5v out, but the clock pins (9&10) are only reading low, no sign of anything else from the probe. The probe is set to CMOS mode. Am I dumb? Is the probe borked? How can pins 9&10 be clock pins when you can do pwm stuff on them at the same time anyway? Any advice would be appreciated.
[QUOTE=Meepbob;50024864]So I'm trying to get the hang of using this logic probe I have... I need to use the pulser to be able to detect a frequency is present in a project I'm working on, simple right? Testing on my arduino uno I have the probe hooked up to the arduinos ground pin and 5v out, but the clock pins (9&10) are only reading low, no sign of anything else from the probe. The probe is set to CMOS mode. Am I dumb? Is the probe borked? How can pins 9&10 be clock pins when you can do pwm stuff on them at the same time anyway? Any advice would be appreciated.[/QUOTE]
The physical pins 9 and 10 on the chip itself are clock, the pins that are usable through the connectors are just PWM pins. Those numbers don't correlate to the actual numbers on the ATMega328.
[url]http://foros.giltesa.com/otros/arduino/fc/docs/pinout/uno.jpg[/url]
[QUOTE=Dolton;50024033]Uh, yeah 24 bits is so unbelievably overkill.[/QUOTE]
Yeah, my bad, I was half asleep and thought "digital audio? well, my soundcard does this many bits".
A resolution of 10 bits gives about a 5mV quantisation interval (assuming 5 V), which is probably fine for this.
[QUOTE=Cakebatyr;50024586]
Orange lines imply what is effected.
Specifically I'm looking for [URL="http://www.ebay.ca/itm/USB-2-0-3D-Sound-Card-Adapter-External-Virtual-7-1-Channel-Audio-PC-Laptop-Win7-/381069814012?hash=item58b987e8fc:g:Rw0AAOSwaNBUeD0o"]something like this[/URL] to directly interface with [URL="http://www.ebay.ca/itm/Baofeng-Speaker-mic-UV-3R-Mark-II-UV-100-UV-200-BF-U3-BF-U8-hand-shoulder-radio-/131740848313?hash=item1eac5dd0b9:g:38cAAOSw4UtWSvk7"]a microphone like this[/URL]
I [I]could[/I] wire a TRRS adapter that goes to a normal SP/MIC TRS/TRS input and then a line to the GPIO of my computer, in this case a Raspberry Pi, but I'd like to make my own interface.[/QUOTE]
Is your vocoder a peripheral for the Pi, or a separate chip on its own? If it's separate, you could include it in your USB device and just send the encoded voice data over USB. The datasheet for the AMBE3000 says it can recieve/output un-encoded voice over SPI, and output/recieve encoded packets over UART, which shouldn't be hard to work with.
If you're familiar with any micro architectures, I'd take a look at their products to see what they've got available. Features you'll want are at least 1 ADC channel, a DAC for your audio out (10 bits resolution on both is fine), USB, and 2x SPI and UART for interfacing with the vocoder. Atmel have a ton of microcontrollers that'll fit your spec.
You're also going to need an audio amplifier, since you don't want to drive the headphones/speakers directly from the micro's pins.
While a large amount of bits for audio is pretty much bullshit it's more or less standardized now, you can get a 24 bit audio ADC / DAC for the price of a general purpose 8 bit one.
You can get USB to I2S chips, I2S is commonly used for digital audio so don't confuse it with I2C.
[QUOTE=Zero-Point;50026702]The physical pins 9 and 10 on the chip itself are clock, the pins that are usable through the connectors are just PWM pins. Those numbers don't correlate to the actual numbers on the ATMega328.
[url]http://foros.giltesa.com/otros/arduino/fc/docs/pinout/uno.jpg[/url][/QUOTE]
Ah alright, didn't know that. I was probing the atmega itself though, just putting the probe on the part of the pin that's exposed before it goes down into the socket, not the arduino pin headers. So even when probing the chip directly, would I be able to detect a frequency on pins 9&10? From what I understand the arduino uses an external 16mhz crystal so I thought my probe would be able to detect that if I were to put it on the xtal pins. Am I doing this wrong, maybe there is there some step I'm skipping? Thanks
You should see a 16MHz sine wave on one of the pins, the other pin is being used to drive the crystal so I'm not sure how the waveform looks like there.
[QUOTE=nikomo;50029060]You should see a 16MHz sine wave on one of the pins, the other pin is being used to drive the crystal so I'm not sure how the waveform looks like there.[/QUOTE]
Unfortunately I don't have an oscilloscope. I'm just using the pulser on my logic probe to try to detect the signal but can't seem to. I'm starting to think it's faulty equipment.
Here's the probe reading low on pin 10....
[thumb]http://i.imgur.com/WZHookT.jpg[/thumb]
Pin 10 has the other side of the oscillator on it, it should never be low.
The probe is functioning correctly.
[QUOTE=nikomo;50031831]Pin 10 has the other side of the oscillator on it, it should never be low.
The probe is functioning correctly.[/QUOTE]
From the picture you can see pin 10 is reading low, why is that if it should never be low? Pin 9 reads low as well, even when probing the oscillator directly both pins coming out of it read low.
I'm assuming the big-ass light on the probe means logic state. The picture is so shit, I have no idea what the device even is.
Anyways, if it's actually reading low, it's possible that the probe is sampling so slowly, that it never catches the waveform in high state, or the waveform stays in logic high for so little, the light only barely lights up (16MHz sine wave, and only the top few volts are going to register).
When you order a two sided board but the fab only puts a one sided board in.... FUCK
[img]http://puu.sh/nZFPZ/7826a26b07.jpg[/img]
WHYYY
Where did you order that from? That's bloody hilarious.
I'd doublecheck the gerbers you sent, though.
I'd guess OSHpark from the purple color, panelization and that he's got three peices, but I thought they had way better quality control than that, even if he fucked up the gerbers.
I love the way those bypass caps are laid out though.
[QUOTE=Tobba;50037276]I'd guess OSHpark from the purple color, panelization and that he's got three peices, but I thought they had way better quality control than that, even if he fucked up the gerbers.
I love the way those bypass caps are laid out though.[/QUOTE]
I sent the image over to them and they recognized a bug in their system caused by something or another and are putting 3 more boards through the super-swift service (already in fab since I reported it)
Still a happy camper :)
For purely academic interest, does anyone have any resources on fm radio and specifically fm radio signal jamming (or, more like overloading; having one signal hit a radio before the other one, drowning out the previous one)
if you don't mind about being indescriminate a spark gap will do a fantastic job of killing just about all the bands.
[QUOTE=pentium;50043014]if you don't mind about being indescriminate a spark gap will do a fantastic job of killing just about all the bands.[/QUOTE]
Right but then your own signal wouldnt work, right?
Oh, so do you want to overpower a specific frequency with another transmission.
Hmm, well in that case I got nothing besides a second tunable FM transmitter of equal or greater power.
[QUOTE=pentium;50043216]Oh, so do you want to overpower a specific frequency with another transmission.
Hmm, well in that case I got nothing besides a second tunable FM transmitter of equal or greater power.[/QUOTE]
That's what I assumed; I sort of wanted to know the mathematic behind how much power you need to block out a signal of x strength y km away, etc.
Of course, any fm equipment capable of transmitting a signal in the matter of km would be expensive so this is purely academic interest
It's not hat it's expensive. It's that anyone who tries to publish online a near exact how-to for a high power radio transmitter gets their ass whipped by their regional version of the FCC. You're not even allowed to talk about that shit online unless it's a secure discussion board or word of mouth. Frankly quite annoying because I'd love to read up on home built short-range AMPS repeaters.
Oh no I'm I gonna go to jail for asking
The issue with jamming things, is its trivially easy to find out where the transmitter is.
Especially by this guy:
[t]https://upload.wikimedia.org/wikipedia/commons/d/d6/Ardf_0001.jpg[/t]
If you're interested look up the FM capture effect. It might get you started at least.
[QUOTE=pentium;50043336]It's not hat it's expensive. It's that anyone who tries to publish online a near exact how-to for a high power radio transmitter gets their ass whipped by their regional version of the FCC. You're not even allowed to talk about that shit online unless it's a secure discussion board or word of mouth. Frankly quite annoying because I'd love to read up on home built short-range AMPS repeaters.[/QUOTE]
Which is weird considering how easy high power FM transmission is around the commercial band.
Is there any form of modern version of the [url=https://www.tindie.com/products/reinnovation/dataduino-the-arduino-based-data-logger/]DataDuino[/url]? I have a project here that requires me to log every ten seconds or so an NMEA formatted sentence to an SD/CF card via RS-232.
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Electrical Engineering V3
