alternative to Wifi Shield? recording to SD card / 9" thick wall [resolved]
Scipio
Nigeria
IMPORTANT NOTE: This product is in beta mode. The WiFi shield is known to have reliability issues across different computer configurations. Using it effectively requires advanced technical skills and programming knowledge. Please proceed at your own risk. OpenBCI cannot guarantee that the device will work with your configuration.
This note in the Wifi Shield Starting Guide is off-putting for anyone like me who has virtually no programming knowledge and advanced technical skill. Is there no way of using one's own Router for streaming and recording EEG data to a micro SD card without the Wifi Shield?
Comments
Scipio, hi.
I assume you are asking about the Cyton? You can use the SD card without involving the Wifi Shield. Ganglion does not support SD card. Do you already have an OpenBCI product?
William
@wjcroft Yes, I am asking about the Cyton +Daisy board. My overriding concern is that if I purchased just the Cyton +Daisy without the Wifi Shield, it would not serve to transmit EEG data from an OpenBCI headband (with 16 channels) on a patient's head, across a nine-inch wall, to a Samsung netbook 10 to 15 feet away in an adjoining room? Surely, without the Wifi Shield or Bluetooth (which I understand also has its own compatibility problems), I would have to attempt to improvise by boring a hole through the wall and somehow, if at all possible, connecting the Cyton +Daisy to the serial or USB port of my netbook, using cables passed through the hole in the wall, in order hopefully to be able to stream and view EEG data on my Windows 10 netbook in real time while at the same time recording the data in a 400GB micro SD card installed in the Cyton +Daisy board?
The whole point of this thread is that at OpenBCI, the present situation which obtains in the case of the Wifi Shield is, to my mind at least, unsatisfactory and we ought to be quickly moving forward to the point where using Wifi should not lie within the domain of only those with advanced technical skill and knowledge of programming. It should very soon be merely a matter of using a Router with universally swappable SIMS depending on your location, local service provider and password.
Using Bluetooth as an alternative to the Wifi Shield may not be satisfactory, either, because apart from a reduced data sampling rate, I have cursorily read reports on this forum concerning technical problems with breakout boards and HC-105.
However, having just read one success story, I wondered @wjcroft (William) and @pushtheworld whether the Bluetooth alternative would work for a non-technical person like myself in the sort of set-up envisaged above: monitoring the EEG of a patient (not mine, of course) in an adjoining room across a 9-inch wall on a Windows 10 netbook computer.
Scipio, interesting.
This sounds like a complicated situation. Is your equipment is on the other side of a concrete block wall? The Cyton already uses a form of Bluetooth. So any other "Bluetooth alternatives" you mention would perform similarly.
https://blog.nordicsemi.com/getconnected/things-you-should-know-about-bluetooth-range
That article specifically mentions that concrete walls attenuate severely. The Cyton and dongle use 'BLE' Bluetooh Low Energy 4.0, not Bluetooth Classic (2.x), which has larger range. Could I suggest that you try some tests using OTHER BLE devices first. Such as a BLE audio headset, used with a mobile phone on the other side? If that works, then Cyton has a better chance of getting through the wall.
Perhaps the simplest solution is to just use a USB extension cable. Possible even routed through existing wiring conducts / pathways that are available in ceilings, outlet boxes, etc. A repeater can even extend this length,
https://www.monoprice.com/product?p_id=6149
With a long cable, you could place the dongle in the same room with your subject, and run the cable to the computer.
Regarding Wifi, it is not always clear that even the Wifi Shield signal can penetrate certain kinds of walls. For example, some concrete block has steel reinforcing rods spaced periodically through the holes in the brick. Such rods would attenuate any RF signals.
Regards, William
@wjcroft Thanks, William. The following seems to be the most practicable part of your suggestion:-
However, the part of this suggestion about routing the leads via 'existing wiring conducts/pathways that are available in ceilings, outlet boxes, etc' is less appropriate because the proposed setup would only be a temporary one accommodating a 24 to 48 hour visit.
The cable mentioned above, including the repeater, is 32 feet long. Would not that be enough to just run the cable via the doorways? If this is a 1 or 2 day visit, seems that would be acceptable.
Super flat usb cable exists that can fit under door or window cracks.
https://www.vpi.us/super-flat-20-cables/usb-cable-super-flat-extend-687
@wjcroft Thanks, William, for your kind and useful suggestions. This gives me a confidence boost in my quest to acquire the OpenBCI apparatus to carry out my experiments and test my hypotheses.
@wjcroft Thanks, William. I have had a look at the USB extension cables:-
https://www.vpi.us/usb-active-extension-cables/usb2-extender-cable-1572.
It just occurred to me to ask whether the EEG signals from the OpenBCI headband and Cyton +Daisy would not drop significantly over 32 feet, in addition to being distorted by noise since the USB cables may not be touch-proof or have noise-cancelling properties? My only consolation would be that such noise and drop in signal quality would not greatly affect the recording of the EEG signals in the micro SD card located as it would be in the Cyton +Daisy board.
The USB 'active' extension cables have a digital repeater (receiver / transmitter) built in, that can handle the extra cable length with NO distortion in the usb signals. They are received and re-amplified. There may be other active repeater usb cables on the market. The Monoprice and VPI links should be viewed as suggestions. A good strategy I find, is to look something up on Amazon and check the reviews before purchasing. Then you can even purchase locally, but at least you know other customers have had good luck. The VPI cable link seems to show 20, 40, 50 meters possible.
The dongle at the end of the extension cable converts between the BLE radio waves and USB signals. Since the dongle is in the same room or near the Cyton, radio reception is clear.
Remember, do some Bluetooth tests first with the wall in question. The Cyton and dongle may be able to handle it. You did not say what type of wall material you are dealing with. Drywall / wood may be fine. Whereas concrete / rebar, may attenuate more.
@wjcroft Thanks again, William. Your reply is useful as before. From the point of view of conserving the Cyton +Daisy Board battery power, it would make sense to use a USB cable for transmission of data from it to my computer. From my experience with Bluetooth earpieces for mobile phones, Bluetooth tends to consume more power than conventional earphones. With the type of experiment I will be running, I have been advised that over a 9 to 12 hour period, I will have to change the AAA batteries of the Cyton every 3 hours to maintain good EEG data transmission, presumably both for quality micro SD card recording as well as for quality streaming to my netbook.
Aside from the issue of increased Cyton +Daisy battery power consumption, I think that the average walls one would encounter in hospital wards would permit streaming of EEG data across adjacent rooms using Bluetooth.
Scipio, thanks. re: "From the point of view of conserving the Cyton +Daisy Board battery power, it would make sense to use a USB cable for transmission of data from it to my computer."
The Cyton connects over BLUETOOTH with it's 'dongle'. The dongle plugs into usb. Hence, there is NO usb connection directly to the Cyton mainboard. And no augmentation of Cyton power from the usb. The Cyton is strictly battery powered.
One alternative to the AA battery pack, are various lithium cells, which have much larger mAh capacities. See,
https://learn.adafruit.com/li-ion-and-lipoly-batteries
There are chargers for cells like these. The lithium cells plug directly into the Cyton power connector. That is what I would recommend. There are also extension cords for the power cable. Such that a larger heavier cell could be placed on a nearby surface.
Another power option are so called usb (5 volt) battery packs. These have lithium cells inside, but convert the lithium voltage of about 3.7V, to 5 volts using a power converter. Since these power converters can potentially generate some switching power supply noise on the 5V power lines, the plain lithium battery packs have no possible noise problems.
wjcroft Hi. How does one know that the USB super flat cable and repeater USB extension cable ordered for will fit snugly onto the OpenBCI Dongle? There happen to be many sizes and ypes of USB repeater and super flat cables, some with micro B male heads and others with A male or female heads (https://www.vpi.us/search?q=Super+flat+USB+2.0+CABLES+male+A+to+Male+micro+B&submit_search=Search) Are special adapters/connectors needed?
Most (older) laptops and netbooks use Type A female at the computer. The dongle is Type A male. Thus a Type A male to Type A female will act as an extension cord.
https://www.vpi.us/super-flat-20-cables/usb-cable-super-flat-extend-687
If your laptop happens to use usb mini or usb micro (unusual), there are adapters. Similarly for usb Type C, which is on latest laptops.
Note that the previous link is only 10 feet. If you need more distance, use the ACTIVE usb extension. The flat type cable may be helpful to go under doorways / carpets. So you might combine say a 5 or 10 meter active cable, terminating in the flat, which is limited at about 3 meters (10 feet).
https://www.vpi.us/usb-active-extension-cables/usb2-extender-cable-1572#/length-5_meters
http://www.yourcablestore.com/USB-Cable-Length-Limitations-And-How-To-Break-Them_ep_42-1.html
@wjcroft Hi. What is the maximum effective Bluetooth range of the Cyton+Daisy board and OpenBCI dongle?
From September 14,
https://www.google.com/search?q=bluetooth+4.0+range