[Tutorial] Building your own DIY E-Stim Stereo Device

[19Hellothere83]

Hello there, is it possible to plug an external battery pack into the mains power supply connector of lolol2 original design?

If so, please could someone suggest a suitable one?

Hi Jpl.
Cool to hear you completed the device!
I don't think this built is adequate for battery use... Since batteries will be empty quite fast i believe.
In my opinion there are more suitable designs for battery usage.

I however have no experience with this But maybe someone else here in the forum maybe can help.
I myself am looking for a smaller built with stereo controls with battery....

[lolol2]

Hello there, is it possible to plug an external battery pack into the mains power supply connector of lolol2 original design?

Maybe check out again my first post.

1x 12V power supply - 29,99€ (120W is maybe not needed, but can recommend this one)
For safety reasons make sure to pick one that is double insulated and has some good quality, don't buy cheap ones without any declaration about that!
Of course this device could also be powered by a 12V battery which is also a safe way.

I had ran this setup in the beginning with a 12v battery block because I thought this would be a good idea to have more mobility. But switched later to an external power supply because I never used the device where I hadn't any power source and didn't wanted to charge the battery after every use.
It was a 12 V 3.2 Ah battery and it was able to let the device run for mostly 3-4h with high volume phases.

[19Hellothere83]

Maybe check out again my first post.

[19Hellothere83]

Hello

Since I had the request to explain how I connected the LedBar I will do it here.
Please keep in mind that this is how I made it, and it works for me.
Please let me know if you see any issue or mistake

After several tries (also DYI with the LM3915) I decided to go with this one as it has some awesome displaying options:
https://www.amazon.de/gp/product/B07YZC ... UTF8&psc=1


connection is very easy:
Power supply : +12V and PGND is directly connected to the 12V supply (somewhere after the switch otherwise the ledbar will remain switched on all the time also after flipping theswitch)
LIN and RIN are connected to the input signals directly at the aplifyer
SGND is connected to the ground of the entry signal

Here the connections poorly drawn into lolol2s schematics:

Spoiler: show

pegelanzeige.JPG (47.21 KiB) Viewed 3849 times

[sissyslutwayne]

I would really love to build one of these however I am based in the UK, does anyone have any links to where I can buy the components in the UK (Amazon, Digikey, RS components, etc)

Thanks in Advance

SSW

[steelhorse545]

I would really love to build one of these however I am based in the UK, does anyone have any links to where I can buy the components in the UK (Amazon, Digikey, RS components, etc)

Thanks in Advance

SSW

I’ve got all the components, I’ve just started building so can’t confirm yet whether the transformer is suitable. But somewhere in a list/spreadsheet in this or another thread there’s a tr1005 listed - it’s actually made by Monacor, but listed as ‘unbranded’ on the Cpc Farrell website (but comes in a monacor box). Almost bought other options -it’s been out of stock or awaiting stock for some time - but it’s 10w with speaker taps of 4/8/16 ohms and power taps of 0.625 to 10w, so ought to give max flexibility.
There’s actually a couple in stock still at the mo’
https://cpc.farnell.com/unbranded/tr-10 ... dp/LS01596
About 8£ each, which is actually quite a bit cheaper than listed elsewhere (not that anyone else had stock)

I also bought the higher power resistors at the same time (around 4ohm and 16 ohm).

Regarding amps, there’s a seller on Amazon doing two tpa3116 boards for 20£, dispatched by Amazon - wanted one as a backup amd also a small audio amp to drive some (unrelated) speakers. Also bought healthcareworld pads/ gel at the same time (a user on Reddit mentioned the same supplier’s pads being ok). Soldering on the non- surfacemount components on one board could have been better, but it works ok, and I can always redo it.

For leads, switches, audio connectors and some input level pots it was just easier to order from a few suppliers on eBay rather than faff around trying to optimise postage costs.

Oh, and I went with 2mm pin to 3.5mm mono audio jack for the tens leads, since the connectors are probably easier to find than 2.5mm jacks - and in hindsight it was a sensible idea since I’ve actually got a couple of stereo 3.5 plug to 3.5 socket extension cables which will extend the tens cables - the tens cables are something like 400mm, which isn’t a bad length but maybe a little short to get the (unboxed) electronics off the one side :) Tho there may be longer cables available for more ££ - they vary widely -I got 3 for about 10£ via eBay.

Haven’t bought conductive rubber loops yet, was going to see how well it worked with pads before chucking any more money at it !

HTH :)

[BoundSquirrel]

I'm hoping the DIY crowd can help me out here. I've been happily using my DIY box for some time now. I had one amp go out, which I promptly replaced. Now, on the same channel, when I turn up the volume I get nothing up to a certain volume and then POW I get signal. Not painful, but enough to make me sit up straight! After that, I don't get any volume increase even if I turn it up. At a little more than 50% volume, it cuts out and then starts pulsing; signal-no signal-signal-no signal.

I've checked and double checked all of my wiring and it's all right. Is this an artifact of a bad amp, resistor, transformer, or something else?

[Spielers]

maybe the transformer is wrong connected and so the volt are to low

[BoundSquirrel]

maybe the transformer is wrong connected and so the volt are to low

Thanks, but no the transformer is connected correctly. It has been working properly for over a year, and it is connected exactly how the other channel is, which works as intended.

[steelhorse545]

maybe the transformer is wrong connected and so the volt are to low

Thanks, but no the transformer is connected correctly. It has been working properly for over a year, and it is connected exactly how the other channel is, which works as intended.

In turn, try swapping various connections from one channel to the other. it’s a nuisance but without having test equipment that’s all you can do (other than visual checks). May just be a lousy joint (are you using screw connectors?), but the individual components aren’t particularly fragile or fault-prone.

[BoundSquirrel]

In turn, try swapping various connections from one channel to the other. it’s a nuisance but without having test equipment that’s all you can do (other than visual checks). May just be a lousy joint (are you using screw connectors?), but the individual components aren’t particularly fragile or fault-prone.

Thanks. That's what I was hoping not to do. Everything is soldered except for the amps, which are screw down connectors. I checked all of the connections to ensure that they're sound. I have a multi-meter and checked the resistors; they're reading 5ohm each so they appear good. I've got one more brand new amp- I'll swap that out first to make sure the replacement isn't dead out of the boys. If that's not it, I've got spare resistors to swap in. The only part I don't have extras of are the audio transformers. I would think those are the least likely to fail.

Maybe it's just time to build a whole new box. This one looks like a big giant mess anyway since I've built and rebuilt it about 4 times as I've learned more along the way. it's worked well for 2+years, so maybe I'll just order new everything and try not to zap my junk off with a new build.

[steelhorse545]

In turn, try swapping various connections from one channel to the other. it’s a nuisance but without having test equipment that’s all you can do (other than visual checks). May just be a lousy joint (are you using screw connectors?), but the individual components aren’t particularly fragile or fault-prone.

Thanks. That's what I was hoping not to do. Everything is soldered except for the amps, which are screw down connectors. I checked all of the connections to ensure that they're sound. I have a multi-meter and checked the resistors; they're reading 5ohm each so they appear good. I've got one more brand new amp- I'll swap that out first to make sure the replacement isn't dead out of the boys. If that's not it, I've got spare resistors to swap in. The only part I don't have extras of are the audio transformers. I would think those are the least likely to fail.

Maybe it's just time to build a whole new box. This one looks like a big giant mess anyway since I've built and rebuilt it about 4 times as I've learned more along the way. it's worked well for 2+years, so maybe I'll just order new everything and try not to zap my junk off with a new build.

Cool, checking continuity will help. Actually, just got mine built - made the schoolboy error of using the wrong contact set on the output sockets, and only spotted that by with the ohmmeter. Tho I added a bunch of switches to reverse phase etc, so it’s a bit of a birds nest :/ made worse cos I used some fairly heavyweight speaker cable which is a bit stiff (add your own puns) - I’ll have to rewire it to get it into a decent sized box. But it works ok from initial trials I also added some input pots to control channel volume, and another switch to flip left<>right, but it looks like the (new!) pots may be noisy .. it seems unlikely tbh, tho I’ve got 3 spares to try, so currently just using equal level audio into the amp..now to get my sound sources and vids in the right places, so I can try triphase properly :)

[BoundSquirrel]

Cool, checking continuity will help. Actually, just got mine built - made the schoolboy error of using the wrong contact set on the output sockets, and only spotted that by with the ohmmeter. Tho I added a bunch of switches to reverse phase etc, so it’s a bit of a birds nest :/ made worse cos I used some fairly heavyweight speaker cable which is a bit stiff (add your own puns) - I’ll have to rewire it to get it into a decent sized box. But it works ok from initial trials I also added some input pots to control channel volume, and another switch to flip left<>right, but it looks like the (new!) pots may be noisy .. it seems unlikely tbh, tho I’ve got 3 spares to try, so currently just using equal level audio into the amp..now to get my sound sources and vids in the right places, so I can try triphase properly :)

So, I ordered everything to try Mantrid's build... Except the capacitors apparently. What would happen with that build if it was just the audio transformers with the resistors? What function do the capacitors serve (I ask mostly because they're not in any other build).

So I tried to repair my existing build - replaced the amps, the resistors, and rewired everything. And it doesn't work. The only thing I didn't swap was the transformers, so I believe I roasted them somehow... I got one really sharp spike in one test and now nothing no matter what I do.

So, down until Tuesday while I wait for transformers and more heat shrink butt connectors to arrive.

EDIT: I picked up one of these to show volume and I'm not sure how to connect it.

LED volume indicator

I have one of these for each right and left to get individual volume control.

Amps

The led indicator has power +/-,audio r/l +, and a common audio -. How do I reconcile that I have 2 audio +/- going to a single - on the indicator? If I split the wire to go to both amps, won't that create a short between the amps? Also, should this go immediately after the amps, after the resistor, or on the electrode side of the box? I have no electrical wiring experience except for putting in a few outlets around the house and what I've learned from here so any input would be helpful.

[steelhorse545]

Cool, checking continuity will help. Actually, just got mine built - made the schoolboy error of using the wrong contact set on the output sockets, and only spotted that by with the ohmmeter. Tho I added a bunch of switches to reverse phase etc, so it’s a bit of a birds nest :/ made worse cos I used some fairly heavyweight speaker cable which is a bit stiff (add your own puns) - I’ll have to rewire it to get it into a decent sized box. But it works ok from initial trials I also added some input pots to control channel volume, and another switch to flip left<>right, but it looks like the (new!) pots may be noisy .. it seems unlikely tbh, tho I’ve got 3 spares to try, so currently just using equal level audio into the amp..now to get my sound sources and vids in the right places, so I can try triphase properly :)

So, I ordered everything to try Mantrid's build... Except the capacitors apparently. What would happen with that build if it was just the audio transformers with the resistors? What function do the capacitors serve (I ask mostly because they're not in any other build).

So I tried to repair my existing build - replaced the amps, the resistors, and rewired everything. And it doesn't work. The only thing I didn't swap was the transformers, so I believe I roasted them somehow... I got one really sharp spike in one test and now nothing no matter what I do.

So, down until Tuesday while I wait for transformers and more heat shrink butt connectors to arrive.

EDIT: I picked up one of these to show volume and I'm not sure how to connect it.

LED volume indicator

I have one of these for each right and left to get individual volume control.

Amps

The led indicator has power +/-,audio r/l +, and a common audio -. How do I reconcile that I have 2 audio +/- going to a single - on the indicator? If I split the wire to go to both amps, won't that create a short between the amps? Also, should this go immediately after the amps, after the resistor, or on the electrode side of the box? I have no electrical wiring experience except for putting in a few outlets around the house and what I've learned from here so any input would be helpful.

The capacitor addition appears to set a low frequency cutoff (with the assumption that lower frequencies are undesirable) . In practise, the estim authors are a small number of folks -posting here or whose work is in an archive referenced in (Reddit) r/estim , so maybe it’s not a big concern, it’s a safeguard against bad actors. Omitting ie shorting)the capacitor means there’s no frequency twiddling, ie it’s a flat response.

The other feature of his addiction is some diodes to limit the voltage, not a bad idea but I’m not sure the possible failure modes of psu/amplifier warrant it. I had wondered about adding some to the electrode/output side, but without measuring voltages there it’s impossible to specify anything.

Does that make sense ? - feel free to ask :)

[mantrid]

The capacitor addition appears to set a low frequency cutoff (with the assumption that lower frequencies are undesirable) . In practise, the estim authors are a small number of folks -posting here or whose work is in an archive referenced in (Reddit) r/estim , so maybe it’s not a big concern, it’s a safeguard against bad actors. Omitting ie shorting)the capacitor means there’s no frequency twiddling, ie it’s a flat response.

The other feature of his addiction is some diodes to limit the voltage, not a bad idea but I’m not sure the possible failure modes of psu/amplifier warrant it. I had wondered about adding some to the electrode/output side, but without measuring voltages there it’s impossible to specify anything.

Does that make sense ? - feel free to ask :)

Sorry for the late reply. The Email notification of Milovana seems to be broken.

Together with the resistor the TVS diode limits the power. Since the the output power of the transformer cant be larger than the input power, it does not matter where the TVS diode is located except that it is easier to tailor it if it is before the transformer. For even better protection you can additional add a (poly)fuse in series to the resistor.

The capacitor also protects the transformer against DC and very low frequency currents which are transformed into heat.

The problem with the low frequencies is whether estim authors are aware of the issue and probably not whether they wanna harm you. For estim devices that re-modulate the audio signals these frequencies are neither dangerous nor unpleasant. There exist estim files that try to cause pain using low frequencies: Its reported that this feels stinging. That's a strong indication that this feeling is not just caused by directly stimulating nerves ...