Really? so cheap for a WiFi RC smart car? Yes. You are right.
This WiFi RC smart car is designed and developed based on ESP-12E from ESP8266, which can be controlled by mobile, PC, and wechat (now just in China). All of the documents can be downloaded for the DOIT official site: www.doit.am, including the scheme for car.
After get it, can further develop based on the Lua IDE.
1) Motor Power(VM): 4.5~36V, can power separately;
2) Control Power (VIM): 4.5~9V(10V MAX), can power separately;
3) Module having shortcut module (connect VM and VIM), thus can use one-way power publicly (4.5~9V) to power control board and motor shield board;
Logic Working Current (Iss):≤60mA (Vi=L), ≤22mA(Vi=H);
Driving Working Current (Io): Io:≤1.2A;
Max Dissipation Power: 4W（T=90℃）;
Control Signal Input Voltage: High voltage (2.3V≤VIH≤VIN); Lower voltage (-0.3V≤VIL≤1.5V);
Working Temperature: -25℃～＋125℃
Driven Mode: Double-way large power H-bridge driven;
Support wireless 802.11 b/g/n standard;
Support STA/AP/STA+AP 3-types working mode;
Built-in TCP/IP protocol stack; Support multi-way TCP Client connection (5 MAX);
D0～D8, SD1～SD3: used as GPIO, PWM, IIC, and etc., Port-driven ability 15mA;
AD0: 1-channel ADC;
Power Input: 4.5V～9V (10VMAX); Support powered-USB; Provide USB-debug interface;
Working Current: continual send:≈70mA (200mA MAX) standby：＜200uA;
Support UART/GPIO data communication interface;
Support firmware by remote update;
Support Smart Link;
Working Temperature: -40℃～＋125℃；
Driven Mode: double-way big-power H-bridge driven;
Weight: about 310g (not including battery).
Contact the service, can free get the Android APP source code.
When get the DoitCar, the default mode is AP. Under this mode, the default SSID nameis Doit WiFi, and password is 12345678.
Open the power from the smart car;
Search the AP SSID name DoitWiFi, and then connect it;
Open the APP from your phone, if your has no this APP, please download http://bbs.smartarduino.com/showthread.php?tid=4 and install it.
After connect successfully, can let car Forward, Back, Stop, Turn Left, TurnRight, Left to Accelerate, and Right to Accelerate, etc.
Under the STA mode, the DoitCar can be controlled by phone APP, WeChat, and page frominternet. Note that, if using STA mode, you should firstly download the DoitCarControl.lua (https://github.com/SmartArduino/DoitCar) into the DoitCar. For more details about download methods, please visit the documents on NodeMCU development. Before download the DoitCarControl.luainto the control-board, you must let the SSID name and password in DoitCarControl.lua same as the ones in your router. In addition, in the DoitCarControl.lua, you should rename the car as the one you like (the defaultname is car). This name is used as the device name controlled by mobile phone,Wechat, and web-page.
The following Figure is shown that car is controlled by web-page.
ESP-12E motro shield
Name: ESP-12E motor shield
Using ESP-12 DEV KIT development shieldmodule
Extend the output ports for ESP-12 DEVKIT: SPI, UART, GPIO, AI and 3.3V power interface
Extend 2-ways motor, then can directlydrive 2-ways motor
Design a power switch
Driven cihip: L293D
Doltage for motor: 4.5V-36V
Voltage for ESP control board: 4.5V-9V
Disparate the power of ESP board andmotor for avoiding the interference. In our experiments, for convenience, a shortcut module is used to connect VIN and VM for the power of ESP board andmotor.