Question

write a 2 page paper on data collection on platform based on the ESP-12 Wi-Fi module. It is a microcontroller with the ability to upload data wirelessly. This microcontroller allows us to run on a standalone power supply so that the device does not have to remain plugged into a computer. Our device uses the Arduino IDE to upload any necessary programming to the device. Along with this microcontroller we used several sensors to make our data collection as easy a process as possible.

Answer 1

ESP-12E WiFi module is developed by Ai-thinker Team. core processor ESP8266 in smaller sizes of the module encapsulates Tensilica L106 integrates industry-leading ultra low power 32-bit MCU micro, with the 16-bit short mode, Clock speed support 80 MHz, 160 MHz, supports the RTOS, integrated Wi-Fi MAC/BB/RF/PA/LNA, on-board antenna. The module supports standard IEEE802.11 b/g/n agreement, complete TCP/IP protocol stack. Users can use the add modules to an existing device networking, or building a separate network controller.

ESP8266 is high integration wireless SOCs, designed for space and power constrained mobile platform designers. It provides unsurpassed ability to embed Wi-Fi capabilities within other systems, or to function as a standalone application, with the lowest cost, and minimal space requirement. ESP8266EX offers a complete and self-contained Wi-Fi networking solution; it can be used to host the application or to offload Wi-Fi networking functions from another application processor. When ESP8266EX hosts the application, it boots up directly from an external flash. In has integrated cache to improve the performance of the system in such applications. Alternately, serving as a Wi-Fi adapter, wireless internet access can be added to any micro controllerbased design with simple connectivity (SPI/SDIO or I2C/UART interface).

Features

• 802.11 b/g/n

• Integrated low power 32-bit MCU

• Integrated 10-bit ADC

• Integrated TCP/IP protocol stack

• Integrated TR switch, balun, LNA, power amplifier and matching network

• Integrated PLL, regulators, and power management units

• Supports antenna diversity • Wi-Fi 2.4 GHz, support WPA/WPA2

• Support STA/AP/STA+AP operation modes

• Support Smart Link Function for both Android and iOS devices

• Support Smart Link Function for both Android and iOS devices

• SDIO 2.0, (H) SPI, UART, I2C, I2S, IRDA, PWM, GPIO

• STBC, 1x1 MIMO, 2x1 MIMO

• A-MPDU & A-MSDU aggregation and 0.4s guard interval

. Functional Descriptions

4.1. MCU -

ESP8266EX is embedded with Tensilica L106 32-bit micro controller (MCU), which features extra low power consumption and 16-bit RSIC. The CPU clock speed is 80MHz. It can also reach a maximum value of 160MHz. ESP8266EX is often integrated with external sensors and other specific devices through its GPIOs; codes for such applications are provided in examples in the SDK.

4.2. Memory Organization

4.2.1. Internal SRAM and ROM

ESP8266EX WiFi SoC is embedded with memory controller, including SRAM and ROM. MCU can visit the memory units through iBus, dBus, and AHB interfaces. All memory units can be visited upon request, while a memory arbiter will decide the running sequence according to the time when these requests are received by the processor. According to our current version of SDK provided, SRAM space that is available to users is assigned as below: ▪RAM size < 36kB, that is to say, when ESP8266EX is working under the station mode and is connected to the router, programmable space accessible to user in heap and data section is around 36kB.) ▪ There is no programmable ROM in the SoC, therefore, user program must be stored in an external SPI flash.

4.2.2. External SPI Flash

This module is mounted with an 4 MB external SPI flash to store user programs. If larger definable storage space is required, a SPI flash with larger memory size is preferred. Theoretically speaking, up to 16 MB memory capacity can be supported. Suggested SPI Flash memory capacity: ▪OTA is disabled: the minimum flash memory that can be supported is 512 kB; ▪OTA is enabled: the minimum flash memory that can be supported is 1 MB. Several SPI modes can be supported, including Standard SPI, Dual SPI, and Quad SPI.

Pin Descriptions

NO Pin Name Function

1 RST Reset the module

2 ADC A/D Conversion result.Input voltage range 0-1v,scope:0-1024

3 EN Chip enable pin. Active high

4 GPIO16 GPIO16; can be used to wake up the chipset from deep sleep mode

5 GPIO14 GPIO14; HSPI_CLK

6 GPIO12 GPIO12; HSPI_MISO

7 GPIO13 GPIO13; HSPI_MOSI; UART0_CTS

8 VCC 3.3V power supply (VDD)

9 CS0 Chip selection

10 MISO Salve output Main input

11 IO9 GPIO9

12 IO10 GBIO10

13 MOSI Main output slave input

14 SCLK Clock

15 GND GND

16 GPIO15 GPIO15; MTDO; HSPICS; UART0_RTS

17 GPIO2 GPIO2; UART1_TXD

18 GPIO0 GPIO0

19 GPIO4 GPIO4 9

20 GPIO5 GPIO5

21 RXD UART0_RXD; GPIO3

22 TXD UART0_TXD; GPIO1

Table 2 Pin Mode

Mode GPIO15 GPIO0 GPIO2

UART low low high

FlashBoot low high high

Table 3 Receiver Sensitivity

Parameters Min Typical Max Unit

Input frequency 2412 2484 MHz

Input impedance 50 Ω Input reflection -10 dB

Output power of PA for 72.2Mbps 14 15 16 dBm

Output power of PA for 11b mode 17.5 18.5 19.5 dBm

Sensitivity

DSSS, 1 Mbps -98 dBm

CCK, 11 Mbps -91 dBm

6 Mbps (1/2 BPSK) - 93 dBm

54 Mbps (3/4 64-QAM) -75 dBm

HT20, MCS7 (65 Mbps, 72.2 Mbps) -72 dBm

Power Consumption

❶Modem-Sleep requires the CPU to be working, as in PWM or I2S applications. According to 802.11 standards (like U-APSD), it saves power to shut down the Wi-Fi Modem circuit while maintaining a Wi-Fi connection with no data transmission. E.g. in DTIM3, to maintain a sleep 300mswake 3ms cycle to receive AP’s Beacon packages, the current is about 15mA.

❷ During Light-Sleep, the CPU may be suspended in applications like Wi-Fi switch. Without data transmission, the Wi-Fi Modem circuit can be turned off and CPU suspended to save power according to the 802.11 standard (U-APSD). E.g. in DTIM3, to maintain a sleep 300ms-wake 3ms cycle to receive AP’s Beacon packages, the current is about 0.9mA.

❸ Deep-Sleep does not require Wi-Fi connection to be maintained. For application with long time lags between data transmission, e.g. a temperature sensor that checks the temperature every 100s ,sleep 300s and waking up to connect to the AP (taking about 0.3~1s), the overall average current is less than 1mA.