I think you have a power issue. How many amps is your PSU and how much do the servos consume?

Yeah - I agree with power. A brownout is a disconnect. If it was a blackout, it would stop entirely, or reboot.

a brownout is when one or all of the chips restarts or a peripheral on a chip restarts or a timer restarts. Usually it’s peripherals like timers or dma buffers etc.

Thanks guys. Makes since. Everything was going on the robot when it happened. I may have to increase the available amp capacity somehow. Probably need to add another Power Supply and split the load.

Good idea. Brown outs are difficult to identify sometimes. Because the entire micro doesn’t shut down, only parts of it. Sometimes the servos will stop responding and the rest seems to work. Or something will reset. This is because the micro is actually a bunch of little chips doing different things. Some of the things require more amperage than others. Or, they shut down or reset because the chip design can’t provide enough current to one peripheral. So each micro and it’s program configuration will have different behaviors of a brownout.

What I would recommend in a production robot is two batteries. One for the motors and one only for the micro. A common ground would ensure they’re on the same foundation for measuring current. But the positive side of the power would be connected separately to the peripherals (servos motors etc)

Oh btw, for one of my daily driver robots, I use two batteries. One runs the servos and such and another smaller 7.4 lipo runs the ezb and arduino.

Outstanding DJ! That was just what I wanted to know. I had no idea just parts of the micro could brown out.

Thanks also for the placement of the second PS. I was wondering if just a small PS feeding the EZB would do the trick.

A while ago there were several discussions and solutions concerning adding super capacitors to the EZB to help with power brown outs. Jeremie had some very good posts on how to add them and what to use. I can't seem to find any of these posts. Does someone have a link or two to these?

I'm not drawing any power for any servos, motors or lights through the EZB. All of these are fed directly from the power source through separate fused circuits.

As mentioned above I'm having an occasional issue with my EZB v4 browning out and disconnecting from WIFI when I have many servos and motors running at one time. I was going to place a dedicated power supply feeding only the EZB as DJ mentioned. Then I remembered this super Cap fix of @Jeremie . If my thinking is correct I thought it would be more elegant to simply place a cap on the power input of the EZB.

A second PS feeding just the EZB would be difficult to implement in my case. My robot has dual power types depending on how I set relays. One way is 12vdc battery power directly from two 35ah deep cell batteries wired in parallel for better amperage. The other way is from a power supply that converts 120vac to 12vdc. It's a 20 amp converter, When using the AC to DC converter is when I seem to get the brownouts. The batteries, power supply and relays are deep within the robots legs and I only have 12vdc running up into the robot body.

I wonder if a simple DC to DC converter placed just before the EZB would help smooth out the voltage? Any thoughts are welcome.

Hi Dave,  I always prefer to use battery power instead of a transformer. The voltage from a battery is pure and has no noise. Cable length is also a problem, besides the voltage drop it is also catches any noise nearby. Proximity to the transformer is also bad for digital applications. You could use a good quality DC converter.

Hi Dave,

This should get you started, using only plus and negative wires.  maybe Jeremie will chime in too.

https://synthiam.com/Community/Questions/Ping-Jeremie-1663

The super caps we use for the inmoov and it helped a lot. The only trouble is you have to wait a few minutes to reboot the EZB because the power takes forever to drain. A supercap will work for you, I'm sure of it.

Hello Dave,

The best method I found for utilizing supercaps to prevent brownout was this:

Use two 2.7V rated 1F capacitors in series, which is equivalent to a 5.4V rated 0.5F cap.

Keeping in mind proper polarity connect the series of supercaps to the 3.3V rail.

While many people may encourage you to place the supercap on the Voltage input rail, the solution above allows you to use less supercaps to keep the 3.3V rail shored up to prevent brown-out.  Supercaps ain't cheap so the less you can use, the better!

Thanks Jeremie for the info.

Will this fix work even though I'm pulling no amperage through the EZB? My power circuit that feeds the ezb may be sagging when many motors are turning. These motors are attached directly to the Power supply and not through the EZB.

If so I assume that the caps being attached to the 3.3 rail backfeed the needed power when the main power feed sags keeping everything stable in the EZB?

Didn't you have a tutorial or a thread on this forum showing all this?

Thanks again for the help!

Yep, it acts like a mini UPS and will hold the 3.3V power rail up for even a few seconds.

I can do a tutorial, no promises on when I can get it to you though. Got a busy weekend

No worries on the timing. II found these caps at Mouser and have them ordered.

Thanks again for the help.

I assume the cap legs are attached in series between a 3.3vdc regulated power pin and a ground pin (and in the  proper polarity of course) as you mentioned?

That’s correct

1. first cap negative leg to EZ-B ground

2. first cap positive leg to second cap negative leg

3. second cap positive leg to EZ-B 3.3V

You can use the GND from any black pin on the EZ-B and grab the 3.3V from the Analog header red pins or the 3.3V on the UART0 header.

Your the best Jeremie!!!

@Jermie or other knowable builders,

I have built and connected the supercaps as you laid out above. It seemed to attach to the 3.3v rail without issue. I really hadn't tested it under servo load though. Today I have a problem pop up related to this setup.

With the caps installed on the EZB Analog header (Neg caps lead to black ground pin and Pos caps lead attached to the 3.3v power pin), the EZB seems to lock up and will not connect to my network. I'll hear no voice prompt. I will have a green flashing LED and also a steady red LED. With the caps removed from the 3.3v analog header the EZB boots properly and attaches to my WIFI network properly with a voice prompt saying "I have successfully connected to your network". I then get a steady green LED and a steady Blue LED.

One odd thing did happened as I was troubleshooting this issue. With the caps attached and after several attempts to reboot the EZB by power cycling, there was one time it succeeded in booting up and attaching to my WIFI network. However when the voice said "I have successfully connected to your network", she was speaking very fast and the tone was very tinny. She sounded much like Alvin The Chipmunk. When I connected to ARC everything seemed to be working properly. Then, the next reboot (with caps installed) I was back to lockup with no voice prompt.

I haven't changed anything on the robot that I can think of since I installed the Supercaps and the EZB would properly boot and attached to WIFI up until this issue started. I did take apart and then reassemble him but nothing was changed with the control or power systems. Just plugs and bolts taken apart and reattached.

Odd I had a week of proper bootup and connections then today this starts. Does anyone have any ideas what's going on?

I also sent a support question to EZ-Robot about this problem.

I have several other ezb's so I'm in process of switching out. One other question. I noticed the old bottom board that just burnt up has a big flat yellow antenna on it. The label on it says ez-b v4. The newer ezb's bottom board I'm switching to does not have an antenna on the lower board and looks totally different. Obviously this is the newer version. I thought the in performance enhancement of version 2 was in the upper board. Does the lower board give a performance enhancement also?

Hello Dave,

I'm not quite sure what's going on but here are the things I can tell you:

The big yellow antenna that you are referring to is a resettable thermal fuse. We found that the thermal fuse didn't really offer much more protection so we removed it from the design when we updated the lower board.

The chip that has the hole in it is the switching power supply chip.

Try not to move a fully charged super-capacitor (or any capacitor for that matter) onto a PCB as there will likely be an ARC that can damage the electronics, safely discharge a cap with a power resistor, or lightbulb before moving it.

One other thing to note when using a super cap on the 3.3V rail. When resetting the EZ-B you need to wait a while when shutting down as the cap will reverse power the EZ-B until it fully discharges. Turning the EZ-B on and off really quickly with the super cap installed will have very weird results as you'll have the super cap providing low voltage and the SWPS providing 3.3V to the circuit and the Microcontrollers are likely still in a brownout protection state. You need to wait a minute after removing power for the super cap to completely discharge and be ready for power again.

Thanks for taking the time to explain this. I have no doubt that I am the one who blew that chip up. Just kind of wanted to know how I did it. Lol. It all makes sense now.

I installed another tested and known working EZB V4/2. Everything is up and running again.

However the new EZB still locks up when the Supercaps are added. I did not turn the power on and off this time. Just one power on to test boot and connection with the old Cap bank added.

I wonder if one or both caps are damaged. I don't have a capacitor tester to find out. I'll make up another cap bank with a new set of caps tomorrow and try again.

Hmmm, I’ve never experienced lock up when using a supercap. Could you post a picture of your supercaps?

Electrolytic capacitors are fairly hard to damage, unless you connect them in reverse, then they usually go boom

Thanks for the interest Jeremie. I'll attach a couple pics of what I made up and was using. I noticed that the two legs that I have tied together are very close to their side walls. I wonder if they were shoring out? I did have them in a shrink tube that I cut off for these pictures. But thinking it through I don't think it would mater if the caps shell got energized in this setup.

I'm still not able to get My EZB to boot properly with the banked supercaps attached to the 3.3v power rail of the ADC header to try to solve the brown out issue.

I've tried for many days using two different sets of banked supercaps and different methods to try to figure out why it's not working. I can't get it to work consistently with weird results sometimes. The weirdest result is at Mark 11:39 that will make you laugh.

I think It's time to move on and find a different solution I think. Here's a video of my struggles and results if you're interested:

Add a switch then. A super cap is a battery. So unless it’s fully drained, you’ll always have some power. Jeremie explained that earlier.

Humm, A switch, That's a genius idea.

Thanks for the video Dave! Everything looks great in terms of how you hooked it up. I posted a comment on your YouTube video. I believe that brand of cap, or the material it’s made of is likely slow to charge. The slow charge is affecting the output stage (3.3V) of the EZ-B and causing very odd behaviour. I’ll have a look at the brand I use, I know they are aerogel, and let you know.

Thanks Jeremie,

I can't find anywhere in the caps datasheet that says anything about Aerogel. Here's the order page on Mouser of the ones I'm using.

AVX Supercaps

In fact I'm having a hard time finding Aerogel Supercaps anywhere. If you don't mind, what brand are you using and where do you get them?

Hello Dave,

I was just lurking around today. Here are some pictures of my super caps that I’ve never had a problem. Sorry I don’t remember where I got them at but it might help with the name that’s on the caps.  Name on caps say superstor .

This May not help or you already have this script running.

EDITED: I have my caps on ACD7

Right on @Merne! You beat me to it, I was just about to comment that the supercaps I've always used are Cooper-Bussmann PowerStor Aerogel (with Low ESR). My caps were also labeled "Series B". There are other PowerStor caps from Eaton that have worked for me as well.

Datasheet here: http://static6.arrow.com/aropdfconversion/5595f83bc15c9d812700e2f0df7c9c90edf2c0c4/powerstorp_specs.pdf

They are available at Digikey and Arrow, among other places. I got mine from Solarbotics and Digikey.

Maybe it's the ESR value from the caps you have Dave? ESR (equivalent series resistance) will affect how fast a cap charges and discharges, the lower the ESR the better!

Thanks @Jeremie.

@Dave Maybe you should try using the same caps as Jeremy’s or the ones I’m using as a last ditch attempt.

Also I noticed in your video, I’m not sure if your sound amplifier have its  own power source or getting it from the EZB and are you using the caps on the bottom EZB too?

last question please; on your B9 you are using EZB’s too, right.  Is it the same Wi-Fi that you’re trying now on the B9 you’re working on?

I really hope you get this figured out as you have spent a lot of time and love of labor putting this B9 back together.

Cheers, merne

@Dave,

I just watched you video again.  Have you tried pressing the reset button on that EZB, then reapply the client network for your WiFi network.  I’ve had to do this once in the past for my EZB.  I’m sure you also applied the EZB v41/2 firmware.   Just a thought.

Of course still get the new supercaps that Jeremie  posted.

good luck!

Wow, thanks for the help and tips guys! Great information.

@Jeremie, you mention ESR. I compaired the valus of both your's and mine from their datasheet and this is what I found: The ESR of my current AVX supercaps are rated: 140 ESR Max @ 1000 Hz (m) The ESR of the caps you point me to is : 1 ESR Max @ 1000 Hz (m) That's a huge difference if I'm reading this correctly. I'll be ordering the ones you recommend and see if this works.  I appreciate your help and time spent. I know you're a busy guy.

@Merne, Thanks for all the extra effort and advice. The pics really helped. I will follow your advice and get the caps you guys are using. T answer your questions: No power for any device is being routed through the EZB. Everything, sound amps, lights, motors and servos are wired directly to the power source.  WIFI, Both the robots are using the same wifi network. In fact, the new EZB I installed in this second B9 (after I burnt up it's EZB) was pulled from my personal B9. It already had the sound modification done and proven to work. Saved me some time and effort. I'm pretty sure it has the most recent firmware. I'll double check that. I'll have to relearn how to do that though. It's been years since I've done it. LOL.

I was asking a friend of mine who manufactures ventilator power supplies about this issue. Here area a couple of his suggestions I'll include for food for thought. I'd love to hear your thoughts on them:

Quote:

You should not connect super caps line that across the ezb. All caps look like a dead short at t=0. Because they are super caps they will take a VERY long time to charge to 5t Im almost certain your issue is not brownout. It’s noise from another device on your system creating a pulse on the reset line of your ezb.

Quote:

If it were me I’d instantly increase the power supply current. There is one other thing you can add and that is a TVS (Transient Voltage Suppressor). It’s a special kinda surge absorber. I use them in the ventilator power supplies I manufacture and have them in my robot. They will support the DC rail when magnetic fields collapse - this collapse can cause a spike on the power rail the ground AND the supply. They will keep transitive noise off your rail voltages.

So I'm shopping for the supercaps you directed me through the data sheet you linked to. It looks nothing like what you guys are using. The difference I can see is that the one in the datasheet is rated at 5v not 2.5v.

I assume I only need to use one of these and not have to solder two of the 2.7v caps together?

https://www.digikey.com/en/products/detail/eaton-electronics-division/PB-5R0V105-R/1026757

EDIT: I think I found them. These are 2.5v, 1f Eaton supercapacitors but I don't see that they are Aerogel. What do you think about these?  https://www.mouser.com/ProductDetail/504-B0810-2R5105-R

I see these are the "B" series you are using. first link in this post that you pointed to is for the "P" series.

Hi Dave,

I would get the caps from your edited post, the Ultracapacitors 1F 2.5V EDLC B SERIES CYL,  2 of them.

They are fast charging and B series.  I don’t think it matters what brand, but that would be a question for Jeremie.  I have never had a problem with the caps I am using currently.

As for the Transient Voltage Suppressor I really don’t have any expertise in this area I believe JeremIm does.  However I will look at the quotes out of curiosity.

Out of curiosity what if you took everything off the EZB like the amp And anything else connected to it. Even the super caps you have currently connected and try booting and see if you hear it connect to Wi-Fi every time.

PS, I am by far no expert in any of this. I am a very novice and been away from it a long time and it has changed since DJ form his new company has.

i’m slowly getting back into it myself and have to redo everything for my Inmoov currently.  And I work at a very slow pace because I have a hard time focusing. LOL.  I’m just giving suggestions that I hope work.

good luck, merne

Edited: I forgot to say if it does connect to the Wi-Fi every time with everything disconnected, then I would first put the amplifier back on and see if it does the same thing. If it does it could be your amplifier.

DJ in the past has had me remove everything and put one thing at a time on to see which one is causing the issue that I was having at the time just food for thought.

@Dave yeah sorry I didn't really look at what series the datasheet was. I more wanted to give you the manufacturer name.

I'm unsure what to think of your friend's advice. I don't see cross-talk noise ever being large enough to jump over and trigger the reset line. I have never seen this in all my career.

So capacitors are used for decoupling (shunting AC noise to ground) and for storage. Capacitors may look like a short at t=0 if they are filtering the first rising edge but that wouldn't affect anything because power is not on yet. Until the power supply is actually on and then short-circuited then bad things will happen but at t=0, who cares, it's as if there is not power applied. On switching power supplies, output stage capacitors are used for storage and to keep the output level steady. I am unsure about the ventilator world but in the robotics world, we are dealing with huge current demands and see brownouts happen very often. It's a common problem especially when using large motors. As mentioned, one solution is to increase the current capacity of your power supply but you could end up with an outrageously expensive and huge power supply to meet the demand. In robotics we are always worried about space, so another solution is to increase the output capacitor storage capacity (as you are doing). Yet another one, is to use battery power.

In my experience TVS diodes are not the answer. I have used them and when they see a transient voltage they sacrifice themselves and no longer work. I really wanted them to work because they sound awesome, but they failed me. In any case, TVS diodes are not the answer in this situation, they are not going to help with brownout conditions as this is a current starvation problem, not a transient voltage (high positive/negative voltage spike) issue.

I don't think that there's any reason to doubt that the supercap method works, because it does, both Merne and the Synthiam inMoov are proof that it does work. I'm not familiar with AVX supercaps and I'm not sure the reason why they wouldn't work for you, maybe Aerogel is the key.

Wow Dave reading that post about burning the Ezb chip, I feel your pain , you must have as many replacement boards and EZb's as I have too!xD

Again, WOW you guys! Thanks.

@Merne, You have some real good points and tips there. Actually if I pull the supercaps off the EZB will boot and connect to the network properly. No matter what is connected to it. When I was first was troubleshooting this issue I actually had everything unplugged and fond no difference in behavior. Running bare and free the EZB booted and connected. As soon as I installed the AVX supercaps it would lock up. I'm going to order the caps I found in my edited text. They seem very similar but are not Aerogel. I'll also keep looking for the Aerogel Jeremie mentions.

@Jeremie, I really appreciate you sharing your knowledge, thoughts and insight. I'm learning a lot on this subject. You have helped me understand a lot of what is going. You also have helped me avoid some missteps. I'm looking forward to getting similar caps like you all have and see the difference. This has actually been a fun process so far.

@robo rad, Well, yes I actually have a lot of extra ezb stuff. However I've ran out of boards. LOL.

I have noticed additional behaviors with the caps I currently am using. If I leave them plugged into the EZB they will drain down to t=0 overnight.  As I mentioned I have nothing pulling power through the EZB. Perhaps the EZB it's self is draining them. #If the EZB is turned on with the caps attached in this state the EZB will lock up. #If I pull the caps The ezb will boot and connect just fine. #If after the ezb boots and connects and I plug in the supercaps in the state of t=0 it will disconnect and shut down. The top green LED will continue to flash but there bill be no lights down near the reset button.

@DJ has mentioned using a switch to connect and disconnect the caps after the ezb boots. I've simulated this. I've so far found that if the caps are or near t=0 the EZB will lock up when the switch is closed and the caps are added to the power rail. I still need to test to see if the caps will shut down the ezb if they are charged when the switch is closed. Perhaps if the caps are isolated from the EZB with an open switch while it's turned off the caps will not drain down to t=0.

OK, I'm still using the original AXV supercaps. I let them fully charge yesterday and shut down the robot. Like mentioned above when power is disconnected the relay opens and the caps are disconnected from the EZB.

This morning I turned on the robot. The relay was still opened and caps disconnected. The EZB booted and connected to my network. ARC was started and connected to the EZB. Next I had ARC close the relay, connecting the caps to the rail. No issues at all! Everything stayed operational and connected.

I think as long as the Super caps don't discharge down to near T=0 then this should work. However I still have the new series B caps coming this Thursday from Mouser. I'll wire them in when they get here and see if there is any change in behavior.

Conclusions so far to this point: #When the AXV super caps get down to near T=0 they are seen by the EZB as a dead short and shuts down part of the board, disconnecting it from my network. #When the AXV caps are charged and disconnected from the EZB , the next day when I boot the EZB and connect I'll then close in the charged caps and everything remains stable.  #It seems that the EZB drains the caps when all external power is turned off. Perhaps the cap drain happens because the EZB is still trying to draw power to operate.

Questions still unanswered;  #Will the new Series B caps I have yet to use to replace the current AVX caps have this same behavior? New caps coming: Supercapacitors / Ultracapacitors PowerStor / Eaton 1F 2.5V EDLC B SERIES CYL. These have a much lower ESR () (Equivalent Series Resistance) then the AXV caps.  #If the PowerStor / Eaton caps do seem to work for this application do I still need the relay to disconnect them from the EZB when external power is disconnected? #If I still need to disconnect with the relay due to drainage then why is the EZB draining power and why are other builders having success with this modification and I am not?

Quote:

#When the AXV super caps get down to near T=0 they are seen by the EZB as a dead short and shuts down part of the board, disconnecting it from my network.

Quote:

#When the AXV caps are charged and disconnected from the EZB , the next day when I boot the EZB and connect I'll then close in the charged caps and everything remains stable.

Quote:

#It seems that the EZB drains the caps when all external power is turned off. Perhaps the cap drain happens because the EZB is still trying to draw power to operate.

Quote:

#If the PowerStor / Eaton caps do seem to work for this application do I still need the relay to disconnect them from the EZB when external power is disconnected?

Quote:

#If I still need to disconnect with the relay due to drainage then why is the EZB draining power and why are other builders having success with this modification and I am not?

Thanks again Jeremie for keeping me in line and helping me to understand.

The only way I've been able to get the AXV supercaps to work with the Super caps I currently have is with the relay. I'll get the new caps tomorrow and swap them out and pull the relay out of the circuit.

I read in the supercaps data sheet that these caps are very sensitive to soldering heat. They recommend soldering quickly to keep from damaging the caps. I'll be careful not to apply too much heat when soldering the legs together.

Your recommended removing the "other item" I have on the ADC header. I'll do that if needed but it's only an open switch. I don't even have a pull up resistor on it.

Good luck with your new supercaps Dave.  I personally would leave the cap legs a little longer if you have room on the B9, IMO.

My the Robinsons be with you.

Good news. I received my new SuperCaps Thursday evening and installed them yesterday. They are wired and hooked up exactly like the first set shown above. They seem to be working properly now with no EZB lockup on powerup. Wahoo! love

I'm not really sure what the secret is that made the difference. Weather it's the ESR, whatever the "B" series is pertaining to these new caps or I damaged the other set soldering them together. My "gut" tells me that Jeremie is correct that the caps ability to take a quick charge is key.

As far as an operational test I did get one lockup and wifi disconnect while checking things out after the install. I was running all the servos in the robot at the same time, moving them back and forth quickly and repeating this test quickly many times. I think I was depleting the caps and simply drained them of power faster then they could recharge.  I slowed down the servos a little and doing the same testing this never happened again. All and all I'm pretty happy with this now.

Thanks again for all the help. I'll let you know if anything changes.

Here's an update on the of original issue in this thread. This issue continued even after applying suggested solutions in this thread.   Recap and final working solution: #I was having trouble with the EZB disconnecting from the WIFI network and needing to be rebooted before it would work again. This happened when servos moved in a very quick moving animation routine that I had recorded using the servo Recorder and servo Pad. #Servos used are 6 EZ-Robot HD servos. They are all moving at the same time.  #This animation and others created by the servo Recorder using the servo Pad was being played back through an EZ script in ARC when the shutdown happens. There were three separate servo recordings being played back in that script involving the six EZ-Robot HD servos.  #I was advised to attach super caps to the 3.3 ADC power rail to shore up and stabilize any voltage sag caused by the servos drawing peek power when they moved.  #After installing and overcoming an issue with the Super caps not allowing the EZB to fully boot, the original issue of random EZB WIFI disconnection continued. #Conclusion: The Super caps did not fix my issue in my case. After much testing to try to nail down when exactly this happened I have come to believe that my issue surrounds the way I recorded the servo movements.  By me recording very fast and erratic servo movements using the servo Recorder using the servo Pad I believe I was overdriving the servos and the quick back and forth of the DC motors may have caused voltage spicks to feed back to the EZB controller thus causing some of it's components to shut down. #Proof: I have other animations using the same HD servos created by the Servo Recorder using the servo Pad that have slower, more fluid servo movements. I have never experienced any shutdown issues when playing back these recordings through ARC using EZ scripts.  #Solution: I removed the Supercaps and I scraped the three recordings that were causing the shutdown issue. I then used the AutoPosition control in ARC to recreate the wanted animation of the six HD EZ-Robot servo movements. In the EZ Script that I was using I removed the commands to playback the three servo recordings and replaced them with the new AutoPosition action command. After testing this change many times I have had zero shutdowns or issues.  #Remaining questions: What really caused the shutdown? Was it the voltage spick of the DC servo motors backfeeding into the EZB? Was it simply to many Servos drawing peek power too often? Since the issue happens both with a large battery amp hour supply and a AC to DC power converter I'm going with the former. I've found a solution and am moving on.

Unless the EZB shutdown issue pops up again I'm going to say all is well now based on what I outlined above. I am a little disappointed in the results of recording servo movements with the Servo Recorder using the servo Pad in regards to causing my issues. However I don't blame ARC and it's controls. I blame the limitations of the devices I'm using and basic natural cause and effect.

I would love to hear any thoughts on this matter about any of this from you all. Thanks so much for the assistance in my efforts to resolve this.  You guys rock!