Asked — Edited

5V Regulator Faulty


I bought an EZ-Robot kit at Maker Faire last weekend but have been having all manner of trouble getting it to work reliably (difficulty making & maintaining Bluetooth connections, servos chattering under no load/heatsinks getting hot, random board resets & brownouts). I finally figured I might have a faulty board when the HC-SR04 sensor I wired up started smoking. Upon testing, I found that I was getting the full supply voltage (i.e., whatever I was supplying to the power plug) at all the '5v' outs from the board. The 3.3v pin is fine. It makes no difference if I use a 9v battery pack or 12v external PSU, whatever I put in, I get out from the 5v lines.

Is there anything else I should look for before I open an RMA ticket?




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United Kingdom

Check the connections on the underside for any shorts.


The wiring schematic for the hc-sr04 is tricky, gnd and V are on opposite side, trigger and Echo are in the middle. Check your wiring. B-tooth connection uninstall and re-install the driver, if possible use external driver and not the built in Microsoft driver. What operating system are you running? If I am not mistaking EZ-B board can only put out 5V and 3.3V ( hint the 5 Amp fuse, will blow if large current or large voltage running across the boardboard as @rich stated above check your board and all wires connection for any miniscule sign of shortage.

United Kingdom

Fuses don't blow on over voltage, only over current (although ohms law will come in here). The problem doesn't appear to be with his accessories if the VCC is more than 5V, it sounds like a short on the regulator


And that fuse is not a fast blow , it can draw ten amps for a short time and not blow the fuse. If you accidentally reversed the power and ground or power through the other pins you could let some smoke out of the sensor. Good news is lots of people have done it and they are low cost.

Connection issues Are 90 percent of the time due to using unsupported aftermarket Bluetooth stack. You can try uninstalling the Bluetooth then unplugging it and plug it back in. Win 7 will install the default drivers by itself.


I had bluetooth issues when I first got my ezb. I had to get a Roadrunner Bluetooth dongel from best buy. It's made for windows 7. Around $15. I was lucky enough to have a $5 rewards certificate to use as well.


Based on your post that the 5 v buss is not regulated, it's time to contact support for a replacement EZ-B


All I can say is don't let it get you down, ez-robot customer service rocks and when (not if) you get this sorted, ez-b rocks as well.


Thanks for the advice, folks. I realize that the issues I experienced may not necessarily be related, but first and foremost I need to make sure the board itself is legit. I did have a quick scan for shorts and couldn't find anything obvious. I'll take another pass tonight, but I suspect I'll have to send this one back. Thanks for your help!

United Kingdom

Use the Contact Us page and they will sort you out. I've not had to deal with a return myself but I have heard that they are very good, they are very good at everything else so I'm sure you'll get it sorted. Hopefully it hasn't put you off using the EZ-B :)


Is there another way to contact the support folks? I've tried sending two messages via the 'Contact Us' page but so far no-one has replied.



United Kingdom

Alan, DJ and Lori frequent the forum but no, the contact page is pretty much the only way. When DJ sees this he will probably look into what's happened their end. :)

Looks like there are a few in the office so chances are someone will be on shortly - although don't quote me on that :)


Ok, well I'll be patient for a few more days. I notice that they have some sort of postal address which I think can be used for sending some kinda paper-based message? Sounds terribly old fashioned but maybe I'll try that next :)


@britishmutt - Your first Contact Us message somehow completely slipped by me! I just responded :)