U-blox 7 vk-172 gps module can not get correct readings

Recently, one customer complained:

I bought a U-blox 7 from you and I’m giving it some tests right now and I’m not getting correct readings from it. I’m an application developer and I had to add a compensation element to both latitude and longitude in order to get “correct” readings from it.

GPS data to google data need conversion

Here is the link about how to do it https://drive.google.com/open?id=1MwNTrqJtst3Dpl9qH8Mt3UJhs87ODdf9

SIM7100A 4G Development Board for Arduino Raspberry Pi DIYmall

1 .  Connect the board like this, one micro usb cable to computer, power the SIM7100A board ( pins is supply and GND, you can use DC Power supply to power the board . Power supply voltage:5V-18V, current  about 1.0A, you can adjust the current until the PWR LED turn on

2 . Download document link
User name and password is diymall

3 . Press the switch   until the 2 LEDs turn on (PWR and STA)

4 . Open device manager, then you will see

5 . Right click to install the driver, you need install the driver manually, find the driver file and install it for about 5 times ( you need choose the right system file)

6 . Then the computer will inform you to install the driver, just click and install the driver . After installing, please find the COM port in the device manager

7 . Open SIMCom Wireless Kit software, choose the Simtech Hs-USB AT Port 9001 (here is COM23), click open port, you can input AT commands in the e.g blank place, like AT, ATI

Amazon link      https://www.amazon.com/dp/B078BNWB9X

DIYmall 9G Servo with Arduino UNO R3 Tutorial

Servo control generally requires a base pulse about 20MS,if the degree is not 180 degree, you need adjust the base pulse in the Arduino code

0.5ms—0 degree
1.0ms—45 degree
1.5ms-—90 degree
2.0ms — 135 degree
2.5ms— 180 degree

Below is Arduino code:


#include <Servo.h>

Servo servo1;


void setup()




servo1.writeMicroseconds(2500); // = -90°


servo1.writeMicroseconds(500); // = 0°


servo1.writeMicroseconds(1500); // = 90°


servo1.writeMicroseconds(2500); // = -90°


servo1.writeMicroseconds(500); // = 0°


servo1.writeMicroseconds(1500); // = 90°



void loop() {}



Test result video links:

sweep from left to right:  https://youtu.be/arjDG0e88Bs

From left to middle then to right:  https://youtu.be/LZMyuq_Ohn0

amazon US https://www.amazon.com/dp/B074SH8XRK

email  sales@diymalls.com



DIYmall 9G Servo and Servo Tester

Today, we will learn how to test 9G servo
You need prepare:
9G servo
Servo Tester
USB to TTL serial cable

The connection as below:
9G Servo      Servo Tester  out              Servo Tester in         Serial Cable
Yellow              S                                                  S                                   White
Red                  +                                                   +                                    Red
Brown              –                                                    –                                   Black

Video link  https://youtu.be/1ECQAyoVbqU

Servo link https://www.amazon.com/dp/B012LZKTDO

9g servo link https://www.amazon.com/dp/B074SG74KV