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new hobby thread
thinking about making a computer - HT radio interface
would be cool to write something to write something to Tx/Rx SSTV, CW, and other data

so from my understanding for analog radios..

analog signal received by radio → analog signal fed to speaker

analog mic signal fed to radio → radio transmits analog signal

Attached is the circuit for a kenwood 2 pin style mic/speaker
i dont see why i couldn't hook this up to a microcontroller for prototyping and figure out how to have the board Tx, record/analyze Rx, and write stuff around that


random stuff on quora
>PTT is triggered when the PTT at the top of your diagram (MIC-) is connected to ground (SPK -). When shorted, only a few mA of current flows, so your can use a small transistor as a switch. For example, a '7002 would work. Connect the drain to the PTT (MIC-), gate to an arduino digital output, and the source to ground (SPK-).
>By setting the arduino digital output high, PTT will be triggered.
>Arduinos are generally bad at audio stuff, but you can find some PCM audio libraries or audio shields that can help. The radio expects an audio signal, which as you noticed, arduino can't output without some hacking. So try to get the arduino to just play the file out to headphones. If you can get that to work, then you can use that output as the input to the radio.
i dont see why i couldn't use PWM instead of analog signal. it will have reduced quality due to the square wave not being perfect and introducing some noise, but i think it will be acceptable for testing


>This technical brief highlights the use of a low-pass filter to transform a PWM signal into an
analog signal.
ok cool looks like that will be pretty easy to do
admittedly, signals/circuits shit im almost entirely clueless about


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ive seen this thing using a USB sound card floating about



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get to work boy


ok so obviously one of the goals of this would be SSTV but ic an't find any of teh SSTV protocol details, so thinking about maybe experimenting with making something
figure the 3 variables you can manipulate the output signal is by changing the frequency, changing the amplitude, and altering the duration
so i was thinking of having each of these correspond to R,G,B for a color
put 7 bit color palette as the goal since they're not really differntiable from 8 bit
each one of these in a specified range and increment would correspond to a value
the program would just look for a change in the combination of them to differentiate one pixel to the next
to help that differnetiation i can have 2 bands of frequency that it alternates between, with a dead space in between
that will help with error detection too
at the start of the transmission the sending station can put out a calibration signal to give the receiving station a baseline for the high/low end of teh ranges for how to interpret it
i think in principle its sound. not sure how practical it is depending on the limitations of the radios/radio communication in general


as best i can tell, this is basically a sound card:
except i dont to play to a speaker, in fact the output will be very, very low (since its replacing the microphone in the radio) so i'll have to really knock the voltage down


try connecting it to the scrum output


>thinking about making a computer - HT radio interface

For commercial work or just for fun?


fur fun


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ok so after sifting through a lot of info and kind of working backwards, i think the way to go about this is:
turnkey USB to I2S solution, then attach an externa DAC and ADC
this is why i fucking hate the arduino/raspberry pi community because it heavily obscures the real (and 20x cheaper) solutions
every problem is something solved by using an MCU with all its unneccessary hardware
theres never a deeper understanding/refinement beyond that
so heres a very general layout for what i think this will look like:
there will of course be some circuit stuff i'll have to figure out regarding automatically transmitting when it gets a signal from the DAC (a transistor probly) and some stuff to attenuate the Tx and Rx signals since they're probly the opposite of what most DAC and ADC are expecting, but figure that is going to be simple op amp / potentiometer thangs


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try this


Maybe look into an electric guide before going forward. You may electrocute yourself to death


let that boy cook (ohmicly)


shaddap im smarter than you
i'll post what ive got so far, its an I2S to USB plug and play solution, along with a DAC and ADC
that should be the bones of this thang.. then its just getting input in the right format, getting the clocks set up right, PCB design, and testing


ok so after a few days of reading the tech documents and letting it all soak in im thinking this:
CP2615 USB-IS2 audio bridge
basically a 'plug and play' solution for bridging USB data transfer protocols with IS2 audio protocols
it also provides a master clock and derived clocks for said IS2 protocol
to that i'll connect a WM8761 DAC and a CS5343 ADC. the ADC has some poorly written documentation that leaves a lot of ambiguity, but as best i can tell these should all play together assuming I feed them the right input
so basically i have to figure out how/what needs to be done to condition my signals, as well as how things like the clock gets split up (can i wire the master clock directly to both chips? can i use a transistor to act as a switch to suspend (power save) the ADC or DAC when its not needed? if the chip is in a suspended state does (one of the chips?) hold data in a buffer as it comes online or does it lose it?
idk but it seems the basics of it is coming together
i might change ADC/DAC since i wanted them to both be from the same company but the WM one is actually a seperate company that got swallowed up by the CS so theres obnoxious differences in terminology


fuk u wadain u dumb whore


think im gonna select new ADC/DAC. i dont like the ones i have now and they're a bit excessive, i'd like to standardize to a single company to.. TI maybe?


ok so best i can tell silicon labs is the only name in the game for USB-I2S bridge chips, and they've just recently discontinued production (not very popular?)
anyway ive decided to go with an audio CODEC chip because it makes sourcing and documentation a lot easier, MAX9860 appears to be compatible with CP2615, with flexible master clock input and compatible input/output resolution
plus i dont have to think about how id want to go about splitting up the master clock to suspend the DAC or ADC when its not getting any input, it'll all be internal for the chip


or the CS42L55 which is what they used on their prototyping microcontroler board
probly that one since its guaranteed functional


>This product is no longer manufactured. View Substitutes.
guess i WONT be using the CS42L55




connect the CR receptor to the DTM-WTD


ok i did that now CR is giving me 'that' look


ok now dig your finger down into his DNUT-HOLE and try to induce a P-STATE-ORGSM and see what happens???




this tech support relationship isn't gonna work if you can't follow simple instructions


>shaddap im smarter than you





lel get smart dumb dumb
y u so dumb dumby
hahahah dumby dumbo dumb


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ok so this is just an information diagram i've put together for the Ailunce HD1 using a converter to kenwood 2 pin. it has all the info i wish i would have found in a single picture
able to figure it out by reading the documetnation for the Motorola GP328+ (same pinout as HD1), random radiofag blogs about the baofeng speakers, and direct voltage measurements with what i have on hand


so basically the idea is i'll hook up what would be speaker output to the ADC on my MAX9860 codec after some signal conditioning (signal would normally be driving a speaker, so probly voltage divider to drop it down), the digital audio would be passed through to my PC using the CP2615, some code i've written would analyze and process it, then a response would be the opposite going from digital audio from PC to CP2615, passed to the MAX9860's DAC, some signal conditioning (another voltage divider, since this ALSO would normally be driving a speaker?) then to the radio mic wires (along with a transistor activated by the GPIO pins on my CP2615 to start tx)
seems daunting but i should just start wiring these together on paper or an easy to use cad shit


low current applicatoin so i'll use a BJT. investigating if transistors introduce weird signal stuff that would require more conditioning or preclude their use


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looked at those easy-digi hobby boards that are all over the place that people use along with USB sound cards to do what im doing
followed the traces to figure out what im looking at
ya looks like it just isolates the analog and digital signals from the ADC/DAC and the radio. nothing too special. looks like some low pass filters coming off the analog stuff to filter out DC. not really familiar with octochips or whatever teh fuck those optical digital isolation chips, and im not familiar with their method of PTT. plan on doing a transistor based one. no idea if BJT transistors introduce DC bias into signals it passed through, though i consider its possible (i dont know shit about this stuff, it just seems like a reasonable guess considering what their input is). i suppose if it does i could filter it out on the other side.


ok maybe theres a good reason why this wouldn't work but what if i had the JFET transistor between the DAC and the isolation transformer, i have the DAC output with a DC bias and have it wired in a way so the bias activates the transistor, the signal passes through the transformer which filter all the DC out. smart?


err fuck i mean BJT transistor


spit on it and plug it in again


hey are you the same feller what fixed that organ? i know ur about ur electronix but im thinkin bout gettin an old reed organ from like ~130 years ago.. yu kno nething ab stuff lik that?


no that was duder idk shit about electronics
also realized i cant use the dc bias from the MAX chip because thats intended for the microphone
i can probly use one of the GPIO pins on the CP2615 controlled through software i guess


but ya id guss duder would know something


ok ya so using I2C protocol on the CP2615 i can set a GPIO pin high or low from software side
so since my PTT circuit would be on the isolated, radio side of everything, i'd have the GPIO pin go trhough… actually how the fuck would i isolate it? i guess i could use an octocoupler? hell that would act as a switch in itself wouldn't it? no need for a seperate transistor?
idk i need some sleep. tired..


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jus lik consult the chart i dunno lol



thanks i consulted it but ended up getting 'it' stuck in my garloid again


ok after pouring over the tech manuals for another few days i think i've figured it all out, at least from a top level perspective
the CP2615 has a custom input/output protocol from USB that you can use to interact with stuff on the board, program internal registries, or send small amounts of data to slave devices through I2C
so using that custom IO, i can program the MAX9860, which by default comes in a condition that automatically shuts down upon power up
also using that custom IO, I can set one of the GPIO pins into a high (pullup) or low (pull down) state. thats how i can iniate PTT for the radio


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made this in a tired haze and didn't document it
gonna go line by line through the 100+ pages of documentation i have and cross reference it with a spreadsheet of every pin re: design decisions and requirements
wish me luck


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i think this would be functional?
have to sit down and really go through the circuits, do some math and size all the components


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ok im not pretending this is a good layout but i think its at least fully realized. still have some resistor, capacitors to specify
my voltage dividers, transformers, high pass filters all set up in a way that actually wroks?
fixed a lot from the old one i drew
gonna go to bed, will try and check this in the morning


File: 1630745317218.png (39.58 KB, 500x250, 2:1, Oekaki.png)

some quick notes on how i can improve layout
ok gnite


File: 1630883763530.png (192.49 KB, 1652x1171, 1652:1171, Schematic_PC Radio Interfa….png)

the latest
finding little errors..
making it more readable


i want to look at an baofeng external mic and ensure that i understand its circuit properly


ok im moving onto actual routing of the traces aaaand
its a nightmare. the MAX9860 and the CP2615 dont have very good pin layout
its impossible to connect all the clocks without crossing eachother and using a via
i think i'll just do that. keep the trace lengths between the I2S master, l/r, and bitclock the same, and all 3 go with a via
that way they should all have the same impedance and clock skew ?


File: 1630994896002.png (69.53 KB, 292x594, 146:297, ClipboardImage.png)

a very rough layout with some fucked up partial traces as i try to figure out something that will work
USB changed to female (for attachment to a male-male USB)
will change the audio jacks to solder pads for attaching the wires, i just have those in there so i could visualize the circuit


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sorry this phone camera is soehow 10 years behind he curve
ok i soldered the max9860 and cp2615 to the breakout boards
i suck at it. they're in QFP packages so its a bit of a bitch
at first i was using fluxed wire to solder all the pads, then i was going to flux them up, put the chips on, and put it in the reflow oven
but i didn't have any flux ;_; so i added a little bit of flux paste on top and put the chips on
into the reflow oven with the right heating profile and they seemed to come out ok
i checked the pins for shorts and fixed any that shorted to an adjacent trace
im really bad at soldering, some of the pins aren't actually filled in
hope i didn't fry the boards


>not yachting to colophon and harvesting your own artisinal pine rosin flux
never gonna make it




ok got the diode arrays for the USB power and data lines
they come in an SOT-143 package and are about 1mm by 2mm small as fuck
i guess i could solder a teeny tire wire onto each pin, but i think i might make PCB breakout for each one
will require making a PCB, doing the traces, holes etc

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[ 76 / egy / h / kc / librejp / sp / v ] [ ukko ]