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by gregeric
Fri May 05, 2017 10:30 am
Forum: AIY Projects
Topic: Faulty HAT?
Replies: 19
Views: 2130

Re: Faulty HAT?

sudo apt-get update && sudo apt-get dist-upgrade will get you kernel 4.9 and the Voice HAT drivers/overlay.
by gregeric
Fri May 05, 2017 10:00 am
Forum: AIY Projects
Topic: Faulty HAT?
Replies: 19
Views: 2130

Re: Faulty HAT?

Make sure it's a fully updated image so that you get the overlay, codec & soundcard driver, which only landed last week.
by gregeric
Fri May 05, 2017 9:46 am
Forum: AIY Projects
Topic: Faulty HAT?
Replies: 19
Views: 2130

Re: Faulty HAT?

Your arecord -L is identical to mine, so recording at least should work.

aplay -L is different, probable due to the dtparam - you only have the DAC, no HDMI or analog outputs.

Perhaps try with plain Raspbian to see if the hardware works with the test commands I posted.
by gregeric
Fri May 05, 2017 9:26 am
Forum: AIY Projects
Topic: Faulty HAT?
Replies: 19
Views: 2130

Re: Faulty HAT?

So the drivers are loaded fine. Ouput of arecord -L, aplay -L?

Does this google image have dtparam=audio=on? I can't see snd_bcm2835 in your lsmod, as I have in Raspbian.
by gregeric
Fri May 05, 2017 9:19 am
Forum: AIY Projects
Topic: Faulty HAT?
Replies: 19
Views: 2130

Re: Faulty HAT?

Weird. With no mics attached it should record silence. What does lsmod show? Also arecord -L, aplay -L?

All my testing thus far is on standard Raspbian with the overlay enabled.
by gregeric
Fri May 05, 2017 9:10 am
Forum: AIY Projects
Topic: Faulty HAT?
Replies: 19
Views: 2130

Re: Faulty HAT?

Try adding

Code: Select all

dtoverlay=googlevoicehat-soundcard
to config.txt
by gregeric
Fri May 05, 2017 8:51 am
Forum: AIY Projects
Topic: Faulty HAT?
Replies: 19
Views: 2130

Re: Faulty HAT?

For a quick test of the Voice HAT's mic & playback hardware:

Code: Select all

arecord -Dhw:1 -c2 -r48000 -fS32_LE -twav -d10 -Vstereo test.wav
records a 10sec clip.

Play it back over the speaker with:

Code: Select all

aplay -Dplughw:sndrpigooglevoi test.wav
by gregeric
Fri May 05, 2017 8:39 am
Forum: AIY Projects
Topic: AIY Voice HAT Hardware Reverse Engineering
Replies: 19
Views: 7301

Re: AIY Voice HAT Hardware Reverse Engineering

Driver pads are open drain n-channel MOSFET low-side switches. There appears to be a flyback diode & polyfuse, suitable for small inductive loads (little motors). No idea of the fuse value. The GPIO pin with 10k pulldown resistor is exposed too, so you can use it as an input if you desire. Driver 0-...
by gregeric
Fri May 05, 2017 8:16 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Interfacing a ISO 7816 compliant smart card with the RPi3
Replies: 6
Views: 2306

Re: Interfacing a ISO 7816 compliant smart card with the RPi

As I said in my edit, it seems that pigpio is missing a bitbang Tx capability. Serial comms in ISO7816 is half-duplex on one i/o line with an open collector Tx line wired to the Rx line. The Pi doesn't have open collector outputs, so the diode is used to simulate that: cathode to the Pi Tx line, ano...
by gregeric
Fri May 05, 2017 7:05 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Interfacing a ISO 7816 compliant smart card with the RPi3
Replies: 6
Views: 2306

Re: Interfacing a ISO 7816 compliant smart card with the RPi

You could use Joan's pigpio library to bit-bang the serial i/o, generate the clock, & do the card detect. Your hardware will then be reduced to level shifting (if needed to 5V) & the Schottky diode to combine the Tx/Rx lines. Edit: looks like pigpio bitbanging serial only does read, not write? http:...
by gregeric
Fri May 05, 2017 6:32 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Interfacing a ISO 7816 compliant smart card with the RPi3
Replies: 6
Views: 2306

Re: Interfacing a ISO 7816 compliant smart card with the RPi

You can purchase USB smartcard readers - search for "smartmouse" or "phoenix", commonly available from satellite dish/stb retailers. If you're OK with hardware, you can build one youself from an FTDI FT232 breakout board, smartcard socket, a schottky diode and one resistor. That will clock the card ...
by gregeric
Thu May 04, 2017 1:33 pm
Forum: Advanced users
Topic: Whitling away at Pi3B standby current.
Replies: 0
Views: 1408

Whitling away at Pi3B standby current.

After a sudo poweroff, the Pi3 continues to draw around 95mA. Bar using an external HAT board eg MoPower, WittyPi et al, I took a look to see if there were any hacks to get the current draw lower. Checking out the Pi3 partial schematic , first thought is turning the perfect diode's Q3 off so as to c...
by gregeric
Thu May 04, 2017 11:59 am
Forum: AIY Projects
Topic: Adding into standard Raspbian rather than new image
Replies: 18
Views: 2659

Re: Adding into standard Raspbian rather than new image

For a quick test of the Voice HAT's mic & playback hardware on standard Raspbian : arecord -Dhw:1 -c2 -r48000 -fS32_LE -twav -d10 -Vstereo test.wav records a 10sec clip. Play it back over the speaker with: aplay -Dplughw:sndrpigooglevoi test.wav Edited to emphasise plain Raspbian, not the Google ima...
by gregeric
Thu May 04, 2017 11:33 am
Forum: AIY Projects
Topic: Two HATs ?
Replies: 10
Views: 1796

Re: Two HATs ?

The little daughter board can readily be used directly on a Pi, bypassing the Voice HAT altogether: simply jumper wire it to the i2s & power pins on the Pi's header. What's more, it appears to have been designed such that you can snap off one or both L/R mics, either to increase the stereo separatio...
by gregeric
Thu May 04, 2017 11:05 am
Forum: AIY Projects
Topic: Two HATs ?
Replies: 10
Views: 1796

Re: Two HATs ?

robthez should've wrote: Inside the magazine, you’ll find a Google Voice Hardware Attached on Top (HAT) board, a Voice HAT stereo microphone accessory board, a large arcade button, and a selection of wires. Last but not least, you’ll find a custom cardboard case to house it all in.
by gregeric
Wed May 03, 2017 6:17 pm
Forum: Troubleshooting
Topic: Camera connector on Pi Zero
Replies: 6
Views: 1176

Re: Camera connector on Pi Zero

The black portion of the camera socket is a wedge - when pushed in it both (weakly) secures the cable & at the the same time presses together the cable & connector contacts. Without the wedge, you will not get reliable electrical connections. You could try pushing a thin layer of (for example) plast...
by gregeric
Wed May 03, 2017 9:07 am
Forum: General discussion
Topic: Raspbian kernel headers missing from official image
Replies: 12
Views: 9438

Re: Raspbian kernel headers missing from official image

raspberrypi-kernel-headers gives you the version matching the kernel available on apt-get. I assume your 4.9.25 came from rpi-update, in which case rpi-source is your friend. There is something amiss with dkms, my (esp8089) driver being uninstalled and not automatically rebuilt on apt-get kernel upd...
by gregeric
Wed May 03, 2017 6:15 am
Forum: General discussion
Topic: Raspbian kernel headers missing from official image
Replies: 12
Views: 9438

Re: Raspbian kernel headers missing from official image

raspberrypi-kernel headers is available by apt-get & gives you the headers matching the installed (by apt-get) kernel.
by gregeric
Tue May 02, 2017 1:17 pm
Forum: Troubleshooting
Topic: Brand new Pi Zero W seems to boot but blank screen
Replies: 15
Views: 4514

Re: Brand new Pi Zero W seems to boot but blank screen

Is your ZeroW inside the offical case? The bundled HDMI adapter is too short to connect properly when the Pi is in that case. If so, try again without the case.
by gregeric
Sun Apr 30, 2017 5:08 pm
Forum: General discussion
Topic: Good Low Cost RTC
Replies: 22
Views: 5217

Re: Good Low Cost RTC

A0/1/2 are to set the address for the I2C eeprom on board. For peace of mind, you could easily disable trickle charging by taking the diode out of circuit - crush that glass package. Or, if you have a soldering iron, remove that or the resistor - when hot enough, they will stick to the tip and come ...
by gregeric
Sun Apr 30, 2017 3:12 pm
Forum: Beginners
Topic: Does anyone know the value of this capacitor?
Replies: 5
Views: 744

Re: Does anyone know the value of this capacitor?

Well in this case it seems to be part of an RC time constant / delay, not decoupling - see Burngate's diagram in the link I gave. It's there so that the current limiting switch can be turned on quickly via the diode, but turned off with a delay while discharging through the resistor. Why that behavi...
by gregeric
Sun Apr 30, 2017 2:22 pm
Forum: Beginners
Topic: Does anyone know the value of this capacitor?
Replies: 5
Views: 744

Re: Does anyone know the value of this capacitor?

The component numbering seems to be retained with newer Pi versions. Previously, mahjongg has confirmed C106 as 220nF on a B+. I'd be confident that is still the case on a Pi3. It's likely the exact value won't matter anyway if it's a decoupling capacitor, and may even work without it. Edit: it def ...
by gregeric
Sun Apr 30, 2017 7:00 am
Forum: Beginners
Topic: I think I got the wrong device!
Replies: 9
Views: 1456

Re: I think I got the wrong device!

An ARM microcontroller may be better suited. You can get up to speed very quickly if you choose one which is mbed compatible: https://developer.mbed.org/platforms/ There are some in form factors similar to the Zero. Be careful to selet one which has the ADC or DAC capabilities which you require, bui...
by gregeric
Sat Apr 29, 2017 4:56 pm
Forum: Beginners
Topic: mems microphone
Replies: 7
Views: 2794

Re: mems microphone

That's not an I2S mic, which would allow you to connect it directly to the Pi's I2S port.

Instead, it has an analogue output, & as such needs an additonal ADC board between it and the Pi.
by gregeric
Tue Apr 18, 2017 11:16 pm
Forum: Media centres
Topic: DVB-T2 TV with Raspberry Pi 3?
Replies: 9
Views: 16875

Re: DVB-T2 TV with Raspberry Pi 3?

H265 is/will be suppoorted, but not at the highest resolution/framerate:

viewtopic.php?f=63&t=156434&p=1112221#p1129848

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