September 2014 – Seite 3 – music, gadgets and travelling

More research here…

Earlier i posted about the 5V source next to the micro USB port. Today i found out that the 5V source is active as soon the OTG adapter is connected even if the Lenovo is powered of. So if connected to the OTG cable the Huawei E3331 is still active even if the Lenovo is powered off. Additional the 5V Pins I figured out on the Motherboard are powered toghether with the OTG source with 5 Volts. There is so far no external power source connected. This is weird.

The internal 3.3V source switches off when the lenovo is shut down. So to prevent the modem sucking off the battery i have two options.

Buying a step up converter that makes out of the 3.3v from the sensor connector a 5V source. Second option is to connect a small relay or IC from the sensor source to switch a permanent 5V source from the OTG USB source. Research going on but the options increase in further research.

2014-09-15

Huawei E3331

The Huawei E3331 starts working with a voltage over 4.1V so the Lenovo Miix does only provide 3.3V internally. I will go on further with a step up controller which will be installed also inside the body of the miix.

2014-09-102014-09-14

Huawei E3331 disassembled

First tests are done the stick is working on the pc. After I connected it to the Lenovo Miix 2 i found out that the indication LED is not giving me a feedback. So far I am sure that the supply voltage is too low. So i opened the the case of the Huawei E3331 to find out if there is a voltage regulator inside to power the device with 3.3V from the source i got in my Miix. I measured the connectors through and there is a 3.3V source so maybe i can connect it directly there to get the modem working…

2014-09-102014-09-14

Modem arrived for the Lenovo Miix

I choosed the Huawei E3331 even there is at the moment no way for voice calls. The USB stick is really tiny. Huawei promotes it as the tiniest USB 3G stick available at the moment. So we will see… But first i have to make some tests with it on my PC if it works before get rid of the warranty.