Monthly Archives: January 2015



About end of last month I get this MT7688 board from taobao.
Just have a try recently, result is here:

Good Parts:
1. Temperature is low, about 35C.
2. Better memory, 64MB.

Bad Parts:
1. Wifi signal is very weak, about 5m it drops to -90db. (I think that is antenna problem, clear zone is too small)
2. The chip provider said this chip cost three times more than RT5350.
3. OpenWrt do not have a good support yet, need more contributors, but all datasheet is not open.

Unknown Parts:
1. Power consume is unknown yet, I use 9V power, the average current >0.30A, maybe the LDO power consume is too much.

If I have more time, will do more test later.

VoCore: Wifi Mode Small Issue

I am trying to make openvpn run on VoCore, so I set VoCore to AP mode with WPA2.
Change&Add the following lines to /etc/config/wireless

config wifi-iface
	option device   radio0
	option network  lan
	option mode     ap
	option ssid     VoCore
	option encryption psk2
	option key	TestPassword

If just set the config and then call “wifi” but not “reboot” to restart wireless part, it has an issue that every 10~20 seconds, the network will disconnect automatically.

But after reboot, everything back to normal.
This does not happen when change AP mode to AP+STA mode.
This happens when change from AP mode to encrypt AP mode.

So I guess the driver might have conflict inside. If we do not have to reboot but just call wifi to reset current config, that will be the best.

New Project: Tiny H264 HD USB WebCam

:) This two weeks I am on a new challenge, I am not very happy with current exists HD h264 camera, so I decide to make one of my own.
MJPEG camera might easy to use, but it costs too much network resource. Only choice is usb + h264 camera, but current h264 camera is super big(40mm x 40mm) or super expansive(such as some famous camera on the quadcopter, even most of them are not h264).

My target is to make a super small(I will keep the size as a secret for now. :D), powerful(with high quality microphone), h264 HD USB webcam.

It is really hard to design…due to the digit and analog are very near each other.
I can use some tiny parts to make this come easy(my friend suggest DCDC XCL206A303AR-G which is made in Japan, its cost is really high, almost 1USD for each), but no challenge, no fun, so have to use my poor brain, design it from common parts in market :)

Anyway, the first version board has in factory now, good luck to myself. If everything goes smoothly, later days I will write an adapter app for it on VoCore.

Can you guess out its real size from this layout picture?
Screen Shot 2015-01-20 at 12.07.24

A simple adapter board for USON8 flash(just feel it looks good):

VoCore: How about to make a small wireless audio player?

Just made a simple test on the wireless audio module :)
It is so easy to enhance VoCore to control a headphone.

Let me tell you how easy it is: just connect I2S to the DAC chip, then connect speaker to the DAC chip, that’s all!

So I have an idea…
How about make the world smallest wireless speaker?

I have a Nokia Play 360, not that portable…it use bluetooth to transfer data, that audio quality is not good enough(if you always hear pure CD quality music, you will know how bad the bluetooth speaker). So I have to take it with a wire everywhere.(in fact, I did not take it everywhere except from kitchen to bedroom)

If we make a little cube(mini play 360?), contains 2000mA battery(enough for play 6~8 hours!)… Emm, that might be very cool!

Surround Stereo…5.1, just use wireless connect all of them without a single wire. Maybe this is a solution? 5.1 = 6 x 44.1KHz, 16bits = 8.4Mbps, wireless is far enough for this.

:) But if we want the best audio quality, an audio profession is necessary, this must be a team work.