Slacker's midi clock metronome PLUS tap trigger (AKA TikTakTap)

[lars-musik]

Now here's something I am really proud of. Although admittedly nearly all of the credit for that little invention goes to the forum member Slacker.

After I failed getting an old midi clock optical metronome to work (discussed here), slacker kindly offered support in designing a completely new one with up-to-date parts. So all I had to do was writing up a wish-list and stealing slacker's time by constantly modifying it.

But, in the end, here is a brand new optical midi clock metronome with a REALLY GREAT additional feature: it triggers a relay that in turn can be used to sync all kinds of great things, foremost analog tap tempo effects to a midi clock (in my case to the click our drummer hears and, thanks to this device, now also sees.).
It has got a 9V jack if the midi device powering it doesn't supply enough current (iirc the midi standard only calls for 5mA) to drive the relay driver but my old boss drumcomputer does it without an additional psu.




I recorded a quick demo, because the usefulness is more obvious this way.

Slacker's files:
https://github.com/slackDSP/slack_metro


Wait, I did contribute something besides the wishlist. Here's a 1590a compatible PCB layout for the circuit I did. It used a dual NO-relay (datasheet) to drive two tap effects (tremolo and if I sort the out-of-sync-troubles with my taptation a delay) because I am not sure if you could simply use a Y-cable from one relay output. To sync my BOSS RC-2 I will have to revise the thing, because I think in need a NC-relay.

PCB:

Schematic:

[deadastronaut]

Totally brilliant...

be nice to control tempo from the box too...

[lars-musik]

Thanks, Rob. It goes perfectly with one of those as a central "tap-able" midi clock generator on your board (or for your whole band):
1. Padchokola
2. midihub 6-way

Whereas the first one looks fantastic (you can dial the tempo in per jog-wheel), the tap tempo reacts somewhat sluggish. The second one works great regarding the tap function, but hasn't got an option for numerical dialing in the actual tempo. And it is booting into a non-tapping mode, which makes it somewhat difficult to use. However, both work fine and the tiktaktap functions just as a translator for the midi clock.

I built both of the above mentioned. For the moment our drummer uses the padchokola with an integrated midi splitter (one out to the drum computer as audible click generator, one out to my pedal board and optical metronome).

I am even thinking about a 1590a tremolo with a 3,5mm tap-input jack and loosing the tap switch altogether.
Let's see.

Anyway, it would be quite easy to integrate this little circuit into one of the above if necessary - et voilà.

[Processaurus]

Amazing!!  That's great for modulation effects to stick to the tempo.

I don't think it needs any other features, other than maybe a little switch to change a relay output from NO to NC.  It's great that it is dead simple.

[deadastronaut]

cool...i could have done with that midi hub years ago ....

[electricco]

Great job guys !!!

the Tremolo pedals is it DIY too (is it on this forum too) ?
I'm courious about MIDI implementation on it
Tx

[lars-musik]

Yes, it 's diy, it's theTapflo tremolo by the Electric Druid found here: http://www.electricdruid.net/index.php?page=projects.taplfo. I published the layout here: http://www.diystompboxes.com/smfforum/index.php?topic=109156.msg997441#msg997441. The layout follows basically the original Tapflo Tremolo circuit.

[easilyamused]

This is a great project! I was looking for something like this... Thanks for sharing.

One question: most MIDI devices use an optical isolator on MIDI IN, and sometimes a 74LS14 to sharpen up the incoming waveform. Any reason why at least the isolator was not used here?

Also, If anyone's interested I'm nearly done with an ATtiny85 version (instead of PIC). I'll post when it's done.

[charbot]

BTW, I already wrote a very similar arduino sketch the other week:  http://www.diystompboxes.com/smfforum/index.php?topic=110577.msg1014702#msg1014702   Mine is w/ a promini and installed inside a EH dlx Memory boy.
I would have preferred to use an attiny but I could not get soft.serial  to work reliably.   Hope you have  better luck. 

[charbot]

Not to sell it too hard.... but a nice thing about mine is that it only sends a few tap signals whenever the midi clock tempo is changed which leaves the pedal's original tap switch free to be used to override the midi sync.

[easilyamused]

Charbot, did you set the fuses on your ATtiny85 to use the 8MHz internal clock? Mine seems to be working fine so far ...

[charbot]

Yes, I did set the fuses for 8mhz.  Im pretty sure the problems I was having were related to two hardware issues.   First,  a temperamental opto that seems to work fine on standard serial but only  occasionally on softserial,   and second;  I was trying to run an attiny 85 20-pu off of 3.3v which (i believe) was causing it to have an irregular tempo.       I got just got some attiny 85 10pu's which take a lower supply voltage.  They should operate more reliably on 3v.    I havent had a chance to try it out yet, tho'.

[slacker]

One question: most MIDI devices use an optical isolator on MIDI IN, and sometimes a 74LS14 to sharpen up the incoming waveform. Any reason why at least the isolator was not used here?

No opto isolator was used because this was designed to be powered by the MIDI device that it's connected to, if you add an isolator you can't do this and would need to add a power supply. If you use it just as a metronome then it has no connections to any other device so there's nothing to isolate it from and the relay isolates the taptempo output.
If you need to power it or you build it into a pedal then yes to make it comply with the MIDI standard you should add an opto isolator.

[slacker]

Not to sell it too hard....

No problem sell as hard as you like, the more the merrier. I did consider making it do exactly what your design does but in the end just went with what Lars had requested.

[Arthur_Git]

Hello Lars,

On my search for a way to accurately sync my boss rc-3 to my bandmates' synthesizer, i've come across this thread. Most Loopers under 150 Euros out there aren't feasable for band use which is quite frustrating. Yours and Slackers project looks very interesting concerning this problem.
You mentioned that you were eager to modify the TikTakTap so that it would send the right output to your rc-2.
Did you try that yet? Did it Work? Would be happy hearing from you!

[lars-musik]

Hi Arthur, welcome to the forum!

The solution is very easy and; luckily, there are no alteration to the circuit needed to feed a BOSS RC looper, just  a different relay. My Tik-Tap-Tap operates with a Meder DIP 05-7221 that works as two NO-switches (pinout diagram 21). The jacks are soldered a) to pin 1 and 7 for the first switch and to  b) to pin 8 and 14 for the second one. The coil is operated through pins 2 and 6 although that has to be guessed from the pinout diagram.

Now the important part: If you drop in the double throw switch Meder DIP 05-7251 (pinout diagram 51), pins 1 and 7  still operate as NO switch, so you can hook up a jack for your "standard" tap effects. Pin 8 and 14  on the other hand are now working as a NC switch with is exactly what you need for your BOSS RC.


Summarized: Just build it as shown above and use a Meder 05-7251 (e.g. here. Your looper needs to be hooked to the "Tap 2" jack.

Unfortunately I didn't try this. I ordered the relay and probably received it, but our drummer wanted to get rid of the click completely as we shifted our musical focus from electronic stuff to more brassy stuff. So I use this only for recording nowadays and the looper isn't in the loop at all. But next time I'm in the rehearsal room I might test it (if I find that relay in my messy workbench).

All the best, Lars

[Chewbakka]

Hi
I guess the PIC12F1822 needs to be programmed for this. How did you manage this?

[lars-musik]

I bought this:

https://www.olimex.com/Products/PIC/Programmers/PIC-KIT3/

[CarpathiART]

Hello,

I´m new to the forum and first of all thanks to everyone here for contributing!

This is a great project you´ve put together! I was looking at the same layout for the 16C54 as your preceding project idea but that seemed a bit too much work towards the results. I´m thinking of a way to convert midi clocks to 5V square wave to feed some 555 chips for sync with MIDI devices. This seems like it could be pretty easily produced from what you guys have created here.

My own knowledge towards PIC programming and and the principles behind it is very limited.

Thank you in advance!

K

[lars-musik]

Hi,

can't you use the Tap Out from the PIC? It produces 5V signals for the relay so it might just work with a 555.

Then again, maybe not. Just try it!