FantomXR Posted December 4, 2017 Author Report Share Posted December 4, 2017 (edited) So guys.... yesterday I spent a lot of time in front of my controller. The room, where the controller is placed at the moment, has a carpet. I noticed, that I get a little shock after while walking through the room when touching metal. I was curious too see if it has an impact to my controller. So I walked through the room and after that touched the encoders, which are directly above the OLEDs. And guess what? The whole electronic became unstable: The OLEDs were freaking out (see pic above) and other illuminated buttons which are connected to the electronic went dark for a few milliseconds. I use those buttons to change the colors of my WS2812 LEDs and it seemed that some of these buttons got triggered, because the color of the LEDs were changing too. It seems that I have an ESD problem here. Is there anything I can do to protect my electronic? BTW: The caps of my encoders are made from aluminum, but they sit on a plastic shaft. So I'm not sure how the "shock" made it into the electronic. (//edit: I don't think that I can connect GND to earth on my AC input?) The first thing I'll add is the suggested cap between RST and GND. The second thing is a larger cap between VDD and VSS at the ribbon connector. For the next PCB revision I'll probably change the 10pin IDC to a 14pin / 16pin (or just add another 2pin header and use stronger wires) and add a second VDD and VSS wire for a stronger connection. Another change I'll make is adding another power supply to the unit. I thought about MeanWell LRS-50-5 which comes with 10A at 5V. I hope to get off the ripple that is inducted by the switching regulators which are working inside the case at the moment. Also for next revision maybe I can add the buffers to the PCB with Andys help... we will see ;-) Thanks for now! I'll report back. Edited December 4, 2017 by FantomXR Quote Link to comment Share on other sites More sharing options...
Zam Posted December 4, 2017 Report Share Posted December 4, 2017 6 hours ago, FantomXR said: I don't think that I can connect GND to earth on my AC input? Did that mean your electronic is floating in a metal case not linked to "earth" ? Best Zam Quote Link to comment Share on other sites More sharing options...
FantomXR Posted December 4, 2017 Author Report Share Posted December 4, 2017 (edited) It's a wooden case... Do I have to connect GND to "earth"? Edited December 4, 2017 by FantomXR Quote Link to comment Share on other sites More sharing options...
Zam Posted December 4, 2017 Report Share Posted December 4, 2017 Just now, FantomXR said: It's a wooden case... mmm... maybe a screening will help Just now, FantomXR said: Do I have to connect GND to "earth"? what do you call GND here ? which side of the power supply ? I'll definitely suggest to hook psu primary "GND" to safety earth, especially if you have any metal part accessible by user. For your 0V ref "GND" at secondary, having it hooked at one point is recommanded too... If you have a SMPS fully floating, what you call "GND" is just a reference that may float way far from AC wall plug earth... No offense but please inform yourself, and get used to 0V(ref), Ground, and (safety)Earth concept Especially to avoid any electric shock if fault occur. But also to properly handle current flow and solve "noise" issue , which seem your case here, where your ESD to the system change in an erratic and unstable way your floating "GND". Not to mention some component can be destroyed by ESD... Best Zam Quote Link to comment Share on other sites More sharing options...
Hawkeye Posted December 4, 2017 Report Share Posted December 4, 2017 Quote The first thing I'll add is the suggested cap between RST and GND. Better between SCLK line and GND, you are using 4-wire SPI, right? Many greets and good luck! Peter Quote Link to comment Share on other sites More sharing options...
FantomXR Posted December 4, 2017 Author Report Share Posted December 4, 2017 Dear zam, thanks for your reply. I understand your concerns. The whole case is made from wood and I don't have any metal parts inside yet. I'm aware of the fact, that all metal parts should be connected to "earth". The power supply is a standard notebook power supply, which of course is connected to earth on the primary side. On the secondary side there is no connection to "earth". The 19V from that supply goes into SMPS, which is where I get the 5V from. With that said: I'm familiar with GND and "earth" in the basics. So I made everything as safe as possible. If I got you right you suggest to add a connection from the power supply secondary side (-) to "earth", correct? If I talk about GND I mean secondary in any case. Sorry to be unclear. @peter: ahh! Got you. Thanks! Yes! I use 4-wire SPI. Quote Link to comment Share on other sites More sharing options...
Zam Posted December 4, 2017 Report Share Posted December 4, 2017 Hi Fantom Ok so you have an external supply, does it output 19V AC or DC ??? In case it's DC why are you using a SMPS after and not a DC-DC convertor or regulator ? In case it's AC are you sure your SMPS is able to handle 19v as input ? If everything is safe/no metal part available for user you don't need to connect your electronic 0V to safety earth BUT as your supply chain still unclear to me I'm curious to know what voltage you have between pcb 0V and safety earth (wall plug). Best Zam Quote Link to comment Share on other sites More sharing options...
FantomXR Posted December 4, 2017 Author Report Share Posted December 4, 2017 (edited) It's 19V DC. I didn't use SMPS! This was a translation mistake ... I used those modules (LM2596) after the 19V: https://www.ebay.de/i/171475050668?chn=ps&ul_ref=http%253A%252F%252Frover.ebay.com%252Frover%252F1%252F707-134425-41852-0%252F2%253Fmpre%253Dhttps%25253A%25252F%25252Fwww.ebay.de%25252Fi%25252F171475050668%25253Fchn%25253Dps%2526itemid%253D171475050668%2526targetid%253D382465680857%2526device%253Dm%2526adtype%253Dpla%2526googleloc%253D9061140%2526poi%253D%2526campaignid%253D905417723%2526adgroupid%253D44044883174%2526rlsatarget%253Dpla-382465680857%2526abcId%253D1129326%2526merchantid%253D112201694%2526gclid%253DEAIaIQobChMIh_fj6ajx1wIVCw4rCh1UeQIcEAQYASABEgKtGPD_BwE%2526srcrot%253D707-134425-41852-0%2526rvr_id%253D1383632515512 Anyway: I think I'll replace all of those (3 of them are build in the housing because I thought I also need 3.3V and 12V) by a single 5V 10A AC-DC converter from MeanWell. This sounds much more convenient and professional. Also the specs look better. Edited December 4, 2017 by FantomXR Quote Link to comment Share on other sites More sharing options...
Antichambre Posted December 4, 2017 Report Share Posted December 4, 2017 14 hours ago, FantomXR said: placed at the moment, has a carpet. You felt the thing... Did you try the box somewhere there is no carpet? Human and animals generally have a positive charge, negative charges are more common to synthetic materials. Can be your carpet... Quote Link to comment Share on other sites More sharing options...
FantomXR Posted December 4, 2017 Author Report Share Posted December 4, 2017 Btw: here you can see it in action. The video was made in the same room where also the problems occur. Today it worked the whole day flawlessly. Very strange, that it sometimes works perfect and another day it starts to freak out after 3min. https://www.dropbox.com/s/7ajek30k9qopmlf/Video%2004.12.17%2C%2022%2051%2016.mp4?dl=0 Quote Link to comment Share on other sites More sharing options...
Zam Posted December 5, 2017 Report Share Posted December 5, 2017 Hello Fantom 11 hours ago, FantomXR said: It's 19V DC. I didn't use SMPS! This was a translation mistake ... I used those modules (LM2596) after the 19V Make more sense now 11 hours ago, FantomXR said: Today it worked the whole day flawlessly. Very strange, that it sometimes works perfect and another day it starts to freak out after 3min If it's a ESD issue (Antichambre also suspect it), it may be completely unpredictable... room temp, humidity, what clothes you have today... Put Cu or Al foil everywhere at inner wood panels, you may also reduce EMI/RFI. Wooden case is nice, but if you look you'll never find any manufacturer using wood other way than cover only (over metal) or completely foil protected. By the way, your controller look cool !!! what are you using across fader, RGB led bar ? Best Zam Quote Link to comment Share on other sites More sharing options...
FantomXR Posted December 6, 2017 Author Report Share Posted December 6, 2017 Dear @Zam, you may be right. But I think, that wooden housings are way more complicated to build in a mass production than metal. This is also a reason why you do not find them on the market. Adding an Cu or Al foil is a good idea! Thanks! The LEDs are WS2812B ;-) Quote Link to comment Share on other sites More sharing options...
Zam Posted December 7, 2017 Report Share Posted December 7, 2017 Hello 11 hours ago, FantomXR said: This is also a reason why you do not find them on the market I don't say that, I say wood is used as aesthetic over metal case or with extended metal foil screen. For example I service and mod a Juno 60 yesterday, the bottom/structural panel is plywood, with pcb attached on him, there is adhesive Al foil all around It will also protect for EMI/RFI !! Both way, our lovely midi box can be noisy at digital lines (I learn it the hard way with my build close to discrete audio circuit) as catching perturbation from over populated electronic environment these days (computer, SMPS, all box in our room with digital electronic) Also you say you have 3 DC-DC converter in your build, still 150khz switcher. The one you show is open frame, maybe a screen around them can help too... Best Zam Quote Link to comment Share on other sites More sharing options...
FantomXR Posted December 7, 2017 Author Report Share Posted December 7, 2017 Hi @Zam, do you have a photo of the inside of the Juno 60? I'd like to see how it looks like with the Al foil ;-) Thanks! Best, Chris Quote Link to comment Share on other sites More sharing options...
Zam Posted December 7, 2017 Report Share Posted December 7, 2017 hello The Juno is now closed (with an audio IN mod) but here I find pict (faster to me to google search than opening the enclosure, take pictures, and upload it ...) http://studiorepair.com/gallery/Roland/Juno-60/slides/Roland_Juno-60_Opened_Right__STUDIOREPAIR_09101301_1009108175.html you'll see the voice/cpu board with silver foil behind, the PSU have L plate that also serve as disipator for regulator there is also a foil at left hand bender board. Best Zam Quote Link to comment Share on other sites More sharing options...
FantomXR Posted December 9, 2017 Author Report Share Posted December 9, 2017 (edited) So I now did some changes: I added an 68pF (I had this in stock... I had no other value available without visiting the next electronic shop) ceramic cap between SCLK and GND at the very end of the OLED-Chain. I also added a 10uF on the IDC connector of the OLEDs between VDD and GND. I also added a 100uF on the WS2812B connector. I checked again the wiring and it seemed that the OLEDs were connected to the same power supply as the LEDs. So I changed that! The OLEDs are now powered from a separate PSU. I didn't have time to put the MeanWell PSU into the device... this is a lot of work... I'll do next year ;-) I'll keep testing the device in the next days / weeks and report back! Thanks!! Edited December 9, 2017 by FantomXR Quote Link to comment Share on other sites More sharing options...
Zam Posted December 9, 2017 Report Share Posted December 9, 2017 Just now, FantomXR said: I checked again the wiring and it seemed that the OLEDs were connected to the same power supply as the LEDs. So I changed that! The OLEDs are now powered from a separate PSU. Yes... IIRC you already have issue with your LEDs before with AD chips Seems that those RGB led strip introduce LOT of noise all around. So careful design seem requested ? maybe a topic alone about this can be open, to share and set good practice for designer that introduce RGB leds, which seem to become more and more used by various members now. Best Zam Quote Link to comment Share on other sites More sharing options...
FantomXR Posted December 9, 2017 Author Report Share Posted December 9, 2017 Yes @Zam you are right. I had issues with those LEDs. But since I use a separate PSU for the LEDs the problem is gone! ;-) Well, I'm still not able to run the faders in 11bit because of jitter (regardless if the LEDs are connected or not) but I really don't need that. 7bit is sufficient.... and thats another topic ;-) I also made a design-mistake: The VDD-traces on the LED-PCBs are way too thin. I used about 0,6mm which might not be enough for this current. I expect a current of above 2A when changing the color for the LEDs. Of course I never run them at full brightness! Then they would draw MUCH more. But yes: If you think we would be able to make something "better", than start another topic. I'm happy to help! (but I'm on vacation from tomorrow on ;-) ) Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.