Let me first start off by saying i am not an electronics person by any means
I am wifi enabling my Neato House vac robot so that i can control it via cell phone or via REST. I have the Ardiuno and a USB host shield wired and working just fine when i power the ardiuno from a separate power source ie: my computer usb port. With the Ardiuno usb host shield plugged into my Neato Robot via its usb port it runs perfect. So the next step of my project is to have it operate of the Neato’s power source which is a bunch of AA sized lit ion batteries which output 9+ volts. So i wire up a 5v volt regulator in between the batteries and the Ardiuno. Plug in the Ardiuno and it runs just fine. Then when i plug in the USB cable from the Neato to the Ardiuno USB host shield its almost like it shorts because the Neato shuts down until i unplug the usb cable from the Ardiuno host shield.
I am guessing it has something to do with circuit isolation??
Again i am a n00b with circuit design so feel free to flame me if in the end it results in a solution I also attached an example.
That’s not normally how it should be charged. It has it’s own separate recharging dock and pads. USB port is used for firmware upgrades but I will try and see if I am able to charge it via USB.
undertoe:
So i wire up a 5v volt regulator in between the batteries and the Ardiuno. Plug in the Ardiuno and it runs just fine. Then when i plug in the USB cable from the Neato to the Ardiuno USB host shield its almost like it shorts because the Neato shuts down until i unplug the usb cable from the Ardiuno host shield.
I am guessing it has something to do with circuit isolation??
If you did what I think you did it has everything to do with tying two 5v supplies together. When you say you;
So i wire up a 5v volt regulator in between the batteries and the Ardiuno. Plug in the Ardiuno
Did you wire the output of that 5v regulator to the 5v pin on the Arduino and not into the barrel jack ? If so then what happens when you plug the USB cable in is that the Arduino runs of the USB 5v and ties that to it's 5v pin ... the same one you've now tied another 5v regulator to. Of course both then "fight" to make that common voltage equal to what it's "thinks" is 5v, which will be a little different from each other ... or any other regulator.
I would suggest that you run the Neato’s 9v battery into the Arduino’s barrel jack and let the Arduino’s regulator and voltage routing circuitry do it’s job. It’s also simpler that what you’re presently doing.
Hmmm, OK how about a link to the Arduino that you’re using so us unpaid volunteers trying to help you aren’t wasting too much of our quasi-prime drinking time. :mrgreen:
Who says I don’t multi-task ? I have to carefully time the beers vs commercial breaks in the Miss USA swimsuit competition ! :mrgreen:
And answer these posts. And figure out the scubaguys beacon and the curling guys electronics.
I’ll have to review the shield schematic in more detail as it seems to do something very stupid. It ties the USB 5v to the MAX3421E, which is a 3.3v part. It’s also ties the USB Vbus (5v) to a line it names “3.3v” which doesn’t seem to tie into the Arduino Micro (that would be a good thing) but …
Haha nice, see i though i had it all figured out with game of thrones but looks like i am missing the good stuff.
hmmm so even though i wired it to +3.3v on the Micro the other signals on the SPI are all done via 5v to the 3.3v only host shield… bummer. I have
a pro mini here i will wire up and see. But what was strange if that sheds any light on it is when i connect just the ground to my board it looks like it shorts.
Ok found out what was wrong, one of my wires must have touched the heatsink on the regulator and it exposed the wire lol. My bad, i only found this out after i ripped out all the wires to start fresh on my bread board. As i said N00b, with a capital N!
I know its normal for a decrease of volts to release in the form of energy but is it normal for a volt regulator to get that warm going from 9v to 5v?
Actually no still having the same issue. I attached a better image. Powers up just fine then as soon as i plug the neato into the usb port it trips the neato and causes it to shut down. In fact if i just plug in the ground to the neato onboard battery with the usb plugged in it trips the neato. dont know if that helps.
Check the voltage between the black lead of the 9V battery and the USB cable ground. If it is not 0V, than the neato’s ground isn’t tied to the black terminal of the battery. My guess is that the 9V battery pack is center tapped, with the center tap grounded. That gives a +4.5V and -4.5V supply that they are using to reverse the motors. In that case, you would drive the teensy from the midpoint and +4.5V terminals on the battery pack instead.
Can you measure, w/the ohmmeter, between the black wire you’re using for ground and the ground pin on the Neato’s USB ?
It would seem that you have things wired correctly. That 9v from the battery is reduced to 5v before going into the Teensy’s regulator. There it becomes 3.3v to run both the Teensy and host adapter. How sure are you that the 5v pin on the host adapter’s USB connector is cut from the adapter’s 3.3v bus ? If you disconnect the host adapter from everything and plug it into the Neato’s USB, do you measure any voltage on the host adapter (you shouldn’t) ?
ps - If you’re using a 7805 (or other linear) regulator then yes it’ll become hot. A draw of 250 mA means the regulator is dissipating 1W (0.25A x 4v). That’s a lot w/o a heatsink. I’d guess your system’s draw is more like 100 mA but it’ll still be hot to the touch.
Mee_n_Mac:
Can you measure, w/the ohmmeter, between the black wire you’re using for ground and the ground pin on the Neato’s USB ?
It would seem that you have things wired correctly. That 9v from the battery is reduced to 5v before going into the Teensy’s regulator. There it becomes 3.3v to run both the Teensy and host adapter. How sure are you that the 5v pin on the host adapter’s USB connector is cut from the adapter’s 3.3v bus ? If you disconnect the host adapter from everything and plug it into the Neato’s USB, do you measure any voltage on the host adapter (you shouldn’t) ?
ps - If you’re using a 7805 (or other linear) regulator then yes it’ll become hot. A draw of 250 mA means the regulator is dissipating 1W (0.25A x 4v). That’s a lot w/o a heatsink. I’d guess your system’s draw is more like 100 mA but it’ll still be hot to the touch.
2.5 volts on the usb +/- wires without it being connected to anything. which when the arduino is connected the + & - do go into the host shield. But the host shield is not m
dont know if i am measuring resistance the right way but between - battery and - usb -293 on 2000k setting. No reading if i flip it, should it be negitive? if i flip it nothing.
Also the volt regulator with out the usb connected is mildly warm, when i connect the usb it heats up super quick, like if i touch it it would leave a mark. I disconnected instantly.
Hmm just thinking what would all be involved on using the 2.5v coming off the USB and splicing before connection to the USB host and increasing the voltage to the 3.3v needed
The USB D+ and D- lines will switch between 0v and 5v when sending data. They can be parked at a few voltages to tell the host some info before communications start. You can’t really use them for power.
You measured 293 ohms between the black battery wire and USB connector ground ? And nothing (no reading, blinking reading) when you flipped the ohmmeters leads the other way ? It should read a few ohms if the 2 places are directly connected to each other. This might indicate that the black wire is not a good ground. Perhaps the 9v supply is split as mentioned above or there some other DC-DC converter between it and the Neato electronics or ??
If you don’t use that black wire as ground but instead plug the USB cable into the host adapter and then use the ground on the host adapter board as ground for the Teensy and the 5v regulator … I wonder if it work.
Mee_n_Mac, that did the trick! getting 4.9 volts in the arduino circuit!
The drawing you attached, looks the same as mine. did you do anything different? So for the voltage regulator would i just input to the + battery, ground just hook up the ground on the aurdiuno and then output hook to vin on the aurdiuno.
couple questions though since i would have never figured that out.
Why does it work in that way. Also anything i can do to decrease the wasted voltage since i am taking it from 16.2v to 5v with the regulator.
Also to simulate a usb disconnect (because the neato requires usb to be disconnected to preform any move commands) I have a NPN transistor that i have the base wired to a resistor and the output of a digital pin. then C & E break the + going to the usb port. So then i just flip it to output high when i want to send a command and then low when i am done issuing the command. Do you see any problem with that?
