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I2C communication with Monome Teletype


Thanks @x2mirko I was hoping there was one more switch i’d not flipped or some such :wink:

I purchased an esd safe and fine temperature controlled iron and still didn’t manage to get it! So I’m am a little concerned about going at it over and over in case I damage the board/pads.


Did you enable teletype control in the admin settings ?
Oops, sorry, yes you did.

Try this :

SC.TR.P 1 on TT
with a SC.TR to port 1 on the ER 301.


Lets see a picture of your handiwork.


Yes, had done that, but thanks for the offer, As I said I hoped there was some arcane teletype process that I’d missed/misread.

Well I certainly wouldn’t call it handiwork! I was concerned about any excess solder shorting something else, and when I used a desolderer actually sucked the diode off the board :blush: so I went for the soldering of pads together option.

I’ll get a picture tomorrow when I have a chance to dismantle again, but it seems that the bad solder is the only possibility really.

Any chance that I’ve damaged the pads perchance and there’s no current flow?


I commend you for coming clean. Haha.

I find that is quite hard to do but then I might be out of touch given how much soldering I’ve done especially in the last few years.

This mod needs only about a poppy seed’s worth of solder on each side. So it shouldn’t be so much that you wouldn’t for example be able to confirm a good connection visually.

The other thing to do is double-check your wiring.

Pro-tip for debugging without falling prey to cognitive bias: Separate the data-gathering phase from the analysis phase. So in this case, make a picture of the wiring looking only at the board. Try not to think about the correct wiring. Then bring that picture over to the documentation and then compare.


Thanks Brian

The diode mishap was as a result of an endeavour to resolder the bridge after it did not work…but it appeared to have a good connection visually. The bridge sans diode appears similarly to have a good connection but clearly something is awry.

(edit: although i again must confess to considerably more than a poppy seed’s worth!)

I’ll do as you suggest but the wiring was double checked against the wiki photo by some sharp teenage eyes on a number of occasions. One thing that did give me cause for concern was that there was a few more pins on your Teletype board than mine, and a small rectangle below said pins, but I’ll check it all tomorrow (hopefully…i’ve a full day at work) and send an image for inspection.

Appreciate the help.


@sixnon Sorry if this sounds silly:
does the teletype work by itself?
can you pulse TR 1?


Not silly @phonk but yes. I can, and am indeed digging the ‘80’s code style of working although I’m only a few days in. Of course I’ve plenty to learn, and if I need to resort to finding some professional soldering aid, I’ve still got patch cables in the interim! It’s just a little frustrating, given the the quantity of folks who did the job with their 12 euro soldering irons and no soldering experience who got it up and running without hassle :wink: I reigned in my usual “she’ll be right” attitude, assembled all the correct bits, but to no avail! :grinning:


hi folks, I’m new here, but pretty fascinated by the ER-301 after seeing it around a lot on the lines forum.

quick question that I asked over there, but maybe could be better answered here:

there’s a run planned for these faderbanks by @shellfritsch and some other folks over on that forum, which I understand will run on a Teensy and have i2c connectivity, i2c seemingly mainly aimed at Teletype users.

What I am wondering is if there would be a possibility that something like this could interface directly with the i2c on the ER-301, which could potentially give 16 faders without using any analog inputs. It’d potentially radically change how I would imagine myself using the ER-301 (i.e., lots of manual control).

I don’t have a good understanding of i2c, but it seems that maybe there is a ‘master’ device,’ and in this case, maybe the faderbank would need to be configured as master?


Yes - the firmware for the Faderbank could be modded to act as a master and bypass the Teletype. It would be hard-coded to a certain set of inputs (which could also be modded in firmware). This is pretty trivial and as I did the i2c firmware implementation, I’d be happy to add it in. It has actually been on my radar for a little bit as this isn’t the first request.

I would have to check, but I think there might be a need for a powered bus board in the middle in order to bolster the i2c bus with a pull-up voltage. Once could use the bus board that was designed for the Teletype (without hooking it to the Teletype). These are available today.

Or you could build or buy a TXb when they are available. The TXb is an open-source, eurorack mounted bus board with 3.5mm stereo jacks for the i2c. I’m designing them to be an accessory for the 16n and also to help to bridge i2c between eurorack cases / separate rows.

Here is an in-process prototype; final version will have two 3.5mm jacks, metal panel, and be 2HP.

With a 3D printed jack cap to help avoid accidental patching:


this is a better and faster reply than I could have imagined! thanks!


Damn… This is very very interesting. I’ll be keeping a close eye on how this develops.


Having made considerable mention of the elgance of the ER301 I’m almost embarrased to publicly admit to being responsible for this…but…well I did say I was an agricultural kinda fellow.


Oh boy. That is a little worse than I was expecting :dizzy_face:

I hope there a piece of metal embedded in that solder blob because that vaguely square-ish shape looks like the pads are lifted off the board…let’s see what we can do with this though.

Do you have a volt meter with continuity mode? If yes, could you please test the continuity between the following 2 points?



it may not be quite as much worse as you imagined, as that vaugely square-ish shape is indeed a piece of metal, cut exactingly by me, under the solder blob. The pads have not lifted but do have some of the blackening such as is evident around the base of the mod on the wiki page. My thought was that the pads had been covered by flux residue or some such and so contact was not being made. It was difficult to get solder to take on the bare pads and I was conscious of the 2 second rule.

I will check the continuity, thank you for that, I was looking for just such a mechanism to be sure.

Again I’m conscious that trouble shooting this kind of thing not your responsibility and I’m conscious that I’m somewhat hijacking the thread, so no expectations held this end.


@laborcamp I’m curious if the Teletype freeze issue is still happening with v0.3.13?


I will report as soon as I update.

I am doing three live shows this week, and, honestly, am not %100 if I should update before that or not?


No problem. Take your time. Not updating right before a show is definitely the right thing to do.


I am extremely tempted though!


You can always roll back to any version :slight_smile: