Remote control effects

[theonefromthesky]

Had an idea for a while and just want to run it by you guys...

Remote control effects from guitar.

I already have made a wireless guiar audio set with a free chanel, and got thinking about using the spare to run effects. As its audio I need a tone generator, which got me thinking, use DTMF and then a decoder at the other end.

I want it simple, 8 or so buttons, press latches relay on, second press latches relay off. Simple.

So tone generator ignored for a moment, as thats easy enough.

Heres what I thought;

Decoder ------> 4line to 16 line -------> Latching circuits---> Darlington Driver--> Relays

HT9170 ------>  DM54154 -------------> 74LS373 -----------> ULN2804A ----------> Relays
MT8870                                             CD4013B


Lets see if I have this right in its most basic form

If you input a momentary DTMF tone, the decoder will decode as 4 bit Binary, and then latch that output until you select a new tone, this is then fed in to the decoder to give a single pin output. Feed this output in to a latching circuit, which will output in to the darlington driver and then drive the relays.

The only thing I am not sure on is the 74LS373, its an octal latching circuit (aparantly), but the way I read the datasheet sugests that the latching ocures when you pull the "LE" pin low and any high inputs will be latched. Am I right in this? As If I am its useless, as you would enable one effect go to turn on another which woudl then turn off all the others.

If this is right, is there another alternative chip that will suit the purpose or would 4 of the CD4013B Dual D-Flip-Flip Chips be a better solution and just feed Q in to -Q to get the latch I want?

I did a quick search on the forum and found a similar idea and link to schematic. I just wanted the extra control, so I know the idea is sound, but I was unsure to the latching side of things as having 4 of the cd4013b chips takes up a bit of room. If necessry then fine, but if there is a smaller alternative then great!

Thanks for advice!

J

[R.G.]

I did something similar for a guy and posted it on geofex. Look at "remote footswitch bypassing system" in the index page from 2003.

All you need to do is have your DTMF decoder fire off the latching setup described.

For using the '373, just put the data on the data pins, strobe LE low, and whatever is on the data pins when LE goes high that satisfies the setup and hold times (Tsu and Thold) goes to the output pins.

[R.G.]

The one I've always intended to do in my copious spare time ( ) is to use a pair of PICs with RS232 ports inside to just run serial communications on an RF link or as ultrasonics on the guitar cable itself. Just make the local (on the guitar) PIC sense the switches and spit out what to do. The remote PIC watches the incoming signals and does as instructed. Simple if you have a reliable RF or ultrasonic link.

[Gurner]

The one I've always intended to do in my copious spare time ( ) is to use a pair of PICs with RS232 ports inside to just run serial communications on an RF link or as ultrasonics on the guitar cable itself. Just make the local (on the guitar) PIC sense the switches and spit out what to do. The remote PIC watches the incoming signals and does as instructed. Simple if you have a reliable RF or ultrasonic link.

I'd toyed with this very same idea  ...I didn't pursue cos I reckon if the the player rolls down his tone knob, then bye bye goes your ultrasound carrier too! Plus of all the numerous things that an onboard PIC can permeate into a guitar signal with ....serial output 'pulse trains' are it! (ok, lowish baud stuff).....led pops & clicks are nothing vs a few characters leaving a PIC serial port!