MUFF WIGGLER Forum Index
 FAQ & Terms of UseFAQ & Terms Of Use   Wiggler RadioMW Radio   Muff Wiggler TwitterTwitter   Support the site @ PatreonPatreon 
 SearchSearch   RegisterSign up   Log inLog in 
WIGGLING 'LITE' IN GUEST MODE

Wireless CV transmission?
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3  Next [all]
Author Wireless CV transmission?
pugix
How would I transmit a DC level reading without wires? I have a small muscle sensor that is wearable. I want to transmit its output (0 to 3V DC) wirelessly. The transmitter would have to be wearable, too. Any ideas?

Thanks,
guest
you can get little wireless boards from sparkfun and the like for not too much money. are you ok with some arduino or microcontroller programming? typical scenario is:

DAC->micro->RF->air->RF->micro->ADC

another option is to hack an RC car controller, or other cheap RF devices.
Revok
This tiny bluetooth arduino might be worth looking into: https://www.dfrobot.com/product-1259.html
pugix
Revok wrote:
This tiny bluetooth arduino might be worth looking into: https://www.dfrobot.com/product-1259.html


If I got this, what would I used to receive it and convert to CV?
guest
since it is bluetooth, you would most likely need to use a computer to recieve the signal, and then something like puredata running on the computer to generate a signal. a more generic wireless device would be something like the wixel (https://www.pololu.com/product/1337), and then you would put a DAC on the recieve side (or use PWM on it). with any of these you will have to do some programming, so its probably best to pick a platform that uses a programming interface you are familiar with.
Revok
pugix wrote:
Revok wrote:
This tiny bluetooth arduino might be worth looking into: https://www.dfrobot.com/product-1259.html


If I got this, what would I used to receive it and convert to CV?


I'm not an expert or even experienced with this stuff but I'm pretty sure you can pair it with another bluetooth arduino or similar device and then into a DAC. Check out this link for an example on pairing: http://www.martyncurrey.com/arduino-to-arduino-by-bluetooth/
Grumble
check THIS out.
or this: https://hackaday.io/project/2386-bluebasic-basic-for-bluetooth
or: https://github.com/espressif/arduino-esp32
av500
you could also go old school and use an analog RF link, like ye olde cordless headphones. convert your CV to a frequency, send that through an FM link and convert frequency back to a voltage at the receiver.
JohnLRice
hmmm..... I think you want one of these?


d'oh! Sorry, those are for AC transmission! Mr. Green
pugix
JohnLRice wrote:
hmmm..... I think you want one of these?


d'oh! Sorry, those are for AC transmission! Mr. Green


I couldn't find it on Amazon.com. smile
pugix
guest wrote:
since it is bluetooth, you would most likely need to use a computer to recieve the signal, and then something like puredata running on the computer to generate a signal. a more generic wireless device would be something like the wixel (https://www.pololu.com/product/1337), and then you would put a DAC on the recieve side (or use PWM on it). with any of these you will have to do some programming, so its probably best to pick a platform that uses a programming interface you are familiar with.


This sounds like I would have to learn too much in too short a time. I do know how to program, though.

Thanks,
pugix
Revok wrote:
pugix wrote:
Revok wrote:
This tiny bluetooth arduino might be worth looking into: https://www.dfrobot.com/product-1259.html


If I got this, what would I used to receive it and convert to CV?


I'm not an expert or even experienced with this stuff but I'm pretty sure you can pair it with another bluetooth arduino or similar device and then into a DAC. Check out this link for an example on pairing: http://www.martyncurrey.com/arduino-to-arduino-by-bluetooth/


Thanks. I like the idea of device to device, rather than having to carry around a computer.
pugix
Grumble wrote:
check THIS out.
or this: https://hackaday.io/project/2386-bluebasic-basic-for-bluetooth
or: https://github.com/espressif/arduino-esp32


I was a professional computer programmer for over twenty years. But I've never done any arduino programming. I'll have to look over the language options.
pugix
Revok wrote:
pugix wrote:
Revok wrote:
This tiny bluetooth arduino might be worth looking into: https://www.dfrobot.com/product-1259.html


If I got this, what would I used to receive it and convert to CV?


I'm not an expert or even experienced with this stuff but I'm pretty sure you can pair it with another bluetooth arduino or similar device and then into a DAC. Check out this link for an example on pairing: http://www.martyncurrey.com/arduino-to-arduino-by-bluetooth/


Looking at this in more detail, I think it might work. I have no problem with C programming. I have a project that needs this sooner than later, so I will be experimenting and I'll post what I find.
Jarno
It could be a very helpful module, standalone multichannel hardware wireless cv. Amazed that nobody has done such a thing, either commercial or as a hobby project. Although wireless midi also hasn't caught on, maybe it IS a niche.
Sandrine
I have a bunch of those transmitter/receiver modules like the ones from Sparkfun, they are 315MHz I believe.
The "data" doesn't have to be fed from/to processors. A simple PWM signal would suffice, using a 555 timer chip on the TX and pulse width to DC on the RX. The frequency could be 1 - 4 KHz.

Those TX modules output on one side of the pulse as AM signal so nothing fancy, but should work nicely. A proper length antenna on the receiver boosts range substantially.

My project using those was a shoe-pedal
pugix
Sandrine wrote:
I have a bunch of those transmitter/receiver modules like the ones from Sparkfun, they are 315MHz I believe.
The "data" doesn't have to be fed from/to processors. A simple PWM signal would suffice, using a 555 timer chip on the TX and pulse width to DC on the RX. The frequency could be 1 - 4 KHz.

Those TX modules output on one side of the pulse as AM signal so nothing fancy, but should work nicely. A proper length antenna on the receiver boosts range substantially.

My project using those was a shoe-pedal


You're talking about these:

https://www.sparkfun.com/products/10535
https://www.sparkfun.com/products/10533

They also have 434 MHz versions.

I'll look into these, too. So I wouldn't need arduino?
windspirit
av500 wrote:
you could also go old school and use an analog RF link, like ye olde cordless headphones. convert your CV to a frequency, send that through an FM link and convert frequency back to a voltage at the receiver.


It would be easier to convert to amplitude (muscle sensor controls a VCA on a static high frequency oscillator) and then envelope follow the receiver.

If you want to go the mega hackerish circuit bending route you can hack a baby monitor for a cheap medium range radio transmitter/ receiver. Just add the audio/ envelope follower circuitry and voila.
Sandrine
pugix wrote:
Sandrine wrote:
I have a bunch of those transmitter/receiver modules like the ones from Sparkfun, they are 315MHz I believe.
The "data" doesn't have to be fed from/to processors. A simple PWM signal would suffice, using a 555 timer chip on the TX and pulse width to DC on the RX. The frequency could be 1 - 4 KHz.

Those TX modules output on one side of the pulse as AM signal so nothing fancy, but should work nicely. A proper length antenna on the receiver boosts range substantially.

My project using those was a shoe-pedal


You're talking about these:

https://www.sparkfun.com/products/10535
https://www.sparkfun.com/products/10533

They also have 434 MHz versions.

I'll look into these, too. So I wouldn't need arduino?


Yep, that's right. they are "dumb" TX/RX and respond to pulses whatever size, but lower frequency (1KHz or even 100Hz) squares will give better resolution pulse-width-wise. I tested them up to 19KHz rate but they weren't exactly these so...

I guess on the RX any DC low pass would work unless you want to get fancy
Grumble
Or design a circuit that acts like a servo controller, a 50% pulsewidth gives 0volt, a higher percentage gives a proportional higher positive voltage while going lower as 50% the voltage becomes proportional negative.
pugix
windspirit wrote:
av500 wrote:
you could also go old school and use an analog RF link, like ye olde cordless headphones. convert your CV to a frequency, send that through an FM link and convert frequency back to a voltage at the receiver.


It would be easier to convert to amplitude (muscle sensor controls a VCA on a static high frequency oscillator) and then envelope follow the receiver.


I think I will try this approach first. As long as a carrier is established, I can vary the amplitude of a fixed square wave oscillator on the transmitting side. Then it's easy to add an envelope follower on the receiving end. Also, I can adjust the envelope follower response rather easily.
Sandrine
I'm not sure if that linear output will be good AM but it's worth a try!
pugix
Sandrine wrote:
I'm not sure if that linear output will be good AM but it's worth a try!


I don't mind if the response curve is changed. All I need is some tracking of the sensor. I'd rather breadboard a few simple circuits that learn a new IDE for arduino.
pugix
This is getting a little complicated. I picked up a transmitter/receiver pair and found some videos on using it. One described using HT12E and HT12D chips to transmit a digital code. Next step would be converting the analog signal I want to send to an 8 bit number. So I need a simple 8 bit A/D converter circuit. I could use suggestions here.

As for D/A on the receiver side, I can make an R/2R ladder, since precision is not an issue.

TIA
guest
the ADC08XX parts are pretty easy to use. the ADC0820 doesnt require an external clock.

another way to do it, is to build your own. the simplest is to get a counter IC, and put another R/2R DAC at its ouptput. you then count it up until its output matches the analog voltage, at which point you output the value. you then reset and do another count.
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3  Next [all]
Page 1 of 3
Powered by phpBB © phpBB Group