Hello there, I am currently searching for a good mic to use with my movi board. It will be used inside a Motorhome/RV so it will be tucked away somewhere and the mic will be sitting on a countertop or something of the like. I need a mic that has about a 20-25 ft pick up radius. I have been looking but cannot find anything that works for my needs and doesn’t require phantom power. Any help would be appreciated, thanks.
Well, microphones for this distance usually need an amplified signal, that’s why they all require phantom power. Too bad MOVI’s onboard microphone doesn’t work for you.
Without knowing much about your setup, an amplified microphone like this one: https://amzn.com/B004REA7MG
might be worth giving a shot.
You can power it with MOVI’s external power supply (by using the microphone power jack in series with the Arduino power plug). However, you will need to build a small attenuator circuit to attenuate from line level to MOVI’s microphone jack level. This is described by the “external microphone” topic posts in our forum.
Maybe that helps…
Gerald
[Last edited Jun 30, 2016 02:54:36]
I just did a test of the MOVI board running the Example program (SimpleDebug). I tested the program using the built in microphone with a Television on an its output volume set higher than a normal conversation level. I also had an air conditioner running for an added challenge. The MOVI Boards built in microphone did pretty well if I spoke to it from about 1 foot away although after the Arduino command and the recognition beep it could take several seconds for the voice recognition to trigger the response to a sentence. After several tests. I turned the power off and connected an Audio-Technica Shotgun Microphone ATR6550 to the external Microphone port. This Microphone is powered by a single AA battery and has two positions one for near and one for far sensitivity. Note: Before I connected the Shotgun Microphone I tested the Mics output voltage with a Multi-meter set to AC voltage, Even when I yelled into it I never saw more than about 350 mV on either power setting. So I figured it would be ok for the MOVI A13 chips inputs without needing the two attenuation resistors and a capacitor. The results of this test were good. Them MOVI responded much faster and more accurately at distances of two to five feet. That’s not bad for such a noisy/semi normal environment. http://www.audio-technica.com/cms/wired_mics/a49c539ef22b0215/
[Last edited Jul 06, 2016 19:24:02]
That sounds good indeed!
it could take several seconds for the voice recognition to trigger the response to a sentence
Playing with the threshold will help that problem. Try adding
recognizer.setThreshold(10);
I am attempting the same sort of thing that the first commenter was. After looking at the microphone you suggested ( https://amzn.com/B004REA7MG ), I was able to figure out how to power the microphone through the Arduino, but I don’t know how to connect the other part of it to the attenuator circuit and then to the MOVI board itself and have it be used instead of the original microphone on the board.
Any help is appreciated.
There is a long discussion about a powered external microphone here:
http://www.audeme.com/forum.html#/20160106/external-microphone-5138266/
Look at the response from Gerald in response #9. I built one based on those specs and it works well. In theory, plugging in a microphone into the microphone jack disables the internal microphone. There is currently some question as to whether or not that is happening completely or not as a few of us are experiencing some odd side effects using an external microphone. Regardless, this is a good place to start to build a circuit as describe in that thread.
Dylan,
Did you use the Adafruit DGC microphone that was linked in the post? I have an external microphone with two power connections, which I would connect in series to power the microphone, then it has two wires. I don’t know how to connect these wires to the attenuator circuit, and then attach that circuit to the microphone jack.
My question is how to physically connect these things. A picture of your set up would be extremely helpful.
I used the one recommended by Gerald in that thread:
https://www.adafruit.com/products/1713
Gerald is very particular about the type of mic that is used and prefers that we use one with the same MAX9814 chip that MOVI has onboard, hence the adafruit mic. It might be worth the $7.95 plus some effort in building a box for it for the piece of mind that you’ll get the best possible support from the Audeme guys. For the box, I used one of those slide top mint boxes lined with some plastic salvaged from an old ribbon cable. Be aware though, the mic is smaller than you will imagine looking at the pictures - the way adafruit laid it out, it is very difficult to find screws and nuts that are small enough to secure the mic to the box, and to drill holes precisely enough right beside the large hole for the electret itself.
A useful photo would be difficult to take because the solder points are all barely visible. It kind of looks like this:
/----------
| GND|---------------------------------------------------- To Arduino GND ----------------------
| Vdd|---------------------------------------------------- To Arduino 5V |
| Gain| (long 8-10 foot cable) |
| Out|---------------------------------------------------- To “Line in” on attenuator circuit |
| AR| To GND on Attenuator circuit -------/
----------/
Thanks Dylan, that was super helpful. However, I think I am going to try a pre-amped microphone and attenuate it. I am trying this at my job and I really don’t want to break anything.
Several of the links on this page are 404’d. I ordered the Adafruit 1713 as recommended, but 2 questions remain:
- On the 1713 board it gives 3 possible settings for Gain (60dB, 50dB, 40dB) which one is correct (and why)?
- Speaking of required attenuation, where is that circuit diagram, with proper values listed?
Thanks a lot.
73, Doug
I posted this to another thread earlier:
https://geoffthegreygeek.com/understanding-decibels-part-2/
Scroll to the 40dB attenuator piece.
As for the Gain, I cannot remember what setting I ended up using. Try all three with the Debug on and see which one sounds best when it repeats back what you said. I have a foggy memory of one of them being very noticeably better than the others.