Timeline for Grounding dc project to clean RF noise
Current License: CC BY-SA 3.0
23 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 26, 2016 at 22:34 | answer | added | Sam | timeline score: 1 | |
| Apr 26, 2016 at 20:36 | vote | accept | badweasel | ||
| Apr 26, 2016 at 20:36 | comment | added | badweasel | Thanks for the help and discussion everyone. I got it installed and grounding was very simple to do. Read range is decent but I'm still working on other aspects of the project. If I had more time, an oscilloscope, and it didn't take 3 days everytime I needed to buy a single capacitor - I'd try fixing my circuit instead of grounding it. I'll eventually post about it on my blog and add a link here. Thanks again. | |
| Apr 26, 2016 at 20:18 | history | edited | badweasel | CC BY-SA 3.0 |
added 576 characters in body
|
| Apr 26, 2016 at 13:09 | comment | added | reggie | If the read range is satisfactory on both battery and earthed, it still points to the SMPSU. The earth is simply providing a return path back to the psu. Because you can fix it with a good ground, doesn't mean that's the most practical solution for your needs. | |
| Apr 26, 2016 at 12:58 | comment | added | reggie | Have you any pipes near by the unit? I did mention pipes in my response. | |
| Apr 24, 2016 at 9:47 | comment | added | badweasel | Right. Which is why I asked 2 questions about grounding it that no one has answered yet. Also I'm all for finding the source of the interference. But let's say that the cap reduces the interference by x %, how will that improve the read range compared to just grounding the circuit? I need maximum read range for this application. And a battery gives that range and grounding it gives 95% of that read range. Read my op again. I'm trying to make sure that I ground it in a safe way. | |
| Apr 24, 2016 at 9:42 | comment | added | reggie | Value of cap used depends on the frequency of interference. If you don't know, then you need to try a range of values. But looks like you have your solution, if earthing it is practical. Good luck. | |
| Apr 23, 2016 at 11:08 | comment | added | badweasel | I'll try a capacitor and shortening and twisting my power wires. But as I said connecting gnd to house ground / earth fixes it. I don't have a scope to see exactly what's happening to the dc when I do different things. I had already tried a capacitor between +v and gnd and it had no effect, but it wasn't 1000uF it was 100uF - all I had handy. | |
| Apr 23, 2016 at 11:06 | comment | added | reggie | you may have both common mode CM and differential mode DM problems so require a combination of fixes, but it sounds like CM to me with the limited data you've given. | |
| Apr 23, 2016 at 11:03 | comment | added | reggie | You could also try shielding if you find it to be common mode interference. Put everything inside an earthed tin box. Be careful about heat and electrical insulation mind! | |
| Apr 23, 2016 at 10:57 | comment | added | reggie | If its differential mode interference, then a cap from "Positive of cap to Vcc and Negative of cap to GND" will help. You could also try a range of small value caps from Vcc to earth, and GND to earth, as close to the SMPSU as possible. One needs to find out which type of interference it is, then focus on the relevant solutions. Pay attention to the frequency response of the components you use, a capacitor turns into an inductor above certain frequencies! | |
| Apr 23, 2016 at 10:32 | comment | added | badweasel | I wish there were still radio shacks around so I could drive 5 min and buy caps rather than having to order every component on Amazon. I'll try to get my hands on some. Yes that dc barrel jack has a black gnd and red vcc out the back that goes to the black breadboard. You can sorta see them in the photo. | |
| Apr 23, 2016 at 9:56 | comment | added | Whiskeyjack | I think you are using that black DC jack to power it externally. You must be somehow getting two wires - VCC and GND out of it. Put a 16V or 25V 1000uF capacitor in parallel. Positive of cap to Vcc and Negative of cap to GND. or better yet, solder it to GND and VCC pins on the arduino board. Do the same with 0.1 uF cap. Do this with RFID module as well. Reggie has also pointed out some improvements. You might want to try that. | |
| Apr 23, 2016 at 9:19 | answer | added | reggie | timeline score: 1 | |
| Apr 23, 2016 at 7:38 | comment | added | badweasel | Photo added. On the actual install I won't be using breadboards or jumper wires and will solder all the connections. | |
| Apr 23, 2016 at 7:37 | history | edited | badweasel | CC BY-SA 3.0 |
edit to clarify something for commenter
|
| Apr 23, 2016 at 7:22 | comment | added | Whiskeyjack | Are you using proper arduino board? Or you made one yourself using Atmega328 IC on a PCB? Can you please share an image of the setup? | |
| Apr 23, 2016 at 7:15 | comment | added | badweasel | Your talking on the DC side of the power adaptor? I'm not an EE I'm a dangerous coder with a soldering iron, which is why I'm here asking. So I don't know where you mean that the cap should go - between what and what? And "close to the micro controller" - everything is close to it. It goes DC power plug and then 4 inches of wire and then the arduino. | |
| Apr 23, 2016 at 7:11 | comment | added | Whiskeyjack | One more suggestion - Try adding big filter cap - 16V 1000uF or so at the entry point of wall adapter and 0.1 uF decoupling capacitor as well close to the micro controller. If you are resourceful, try making a PI filter (2 caps 1 inductor). See if it helps. | |
| Apr 23, 2016 at 7:04 | comment | added | badweasel | I've tried 4 or 5 different ones, different manufacturers, some that I bought specifically to power arduino projects, and some that I have around the house like 12v hard drive supplies. | |
| Apr 23, 2016 at 7:02 | comment | added | Whiskeyjack | Have you tried different power supplies? Maybe the particular one you are using is of bad quality and hence causing the issue. If another good quality wall adapter works, you can call it a day. Usually SMPS ICs have frequency between 60 kHz to 120 kHz so there might be a possibility but a well made SMPS should work. | |
| Apr 23, 2016 at 6:57 | history | asked | badweasel | CC BY-SA 3.0 |