China
Africa
Explore chapters and articles related to this topic
Example: Fire-Seeking Robot
Published in Volker Ziemann, A Hands-On Course in Sensors Using the Arduino and Raspberry Pi, 2018
But we do not have enough analog input terminals on the NodeMCU, and have used almost all the IO pins. This significantly limits our ability add new functionality to the robot. We therefore add an Arduino-NANO to the large breadboard and program it to behave as a slave to the NodeMCU, and to communicate over the serial line. The wires that connect the respective TX and RX pins are crossed and behave similar to a null-modem cable. The NANO behaves almost like a UNO and is also programmed in the same way, by selecting Arduino Nano from the Tools→Board menu in the Arduino IDE. The only obviously visible difference is that the NANO has eight instead of six analog input pins, while there are also 13 digital IO pins. Since we power the NANO with 5 V supplied to the pin labeled “5 V”, all IO pins are operating on 5 V logic levels. In order not to damage the NodeMCU that operates at 3.3 V, we use a reverse-biased diode in the connection from the TX pin of the NANO to the RX pin of the NodeMCU. The diode blocks the 5 V from reaching the NodeMCU, but if the TX is pulled low, the signal on the input pin of the NodeMCU is also pulled low. The prototype circuit works with a normal switching 1N4148 diode, but ideally one should use a Schottky diode, which has a smaller voltage drop. Once the essential communication between NodeMCU and the slave-NANO works, we connect the two additional phototransistors from the small breadboard to analog input pins A0 and A1 on the slave NANO. This completes the description of the hardware on the robot chassis, and we can turn to programming the NodeMCU.
VISTATM: Visual Impairment Subtle Touch AidTM – a range detection and feedback system for sightless navigation
Published in Journal of Medical Engineering & Technology, 2022
Bassil Ramadan, Wolfgang Fink, Andres Nuncio Zuniga, Kristena Kay, Nick Powers, Connor Fuhrman, Sunggye Hong
Because of the lack of parallel processing on the selected Arduino microcontroller board due to a single core, 16 MHz processor and limited integrated development environment [17], there is a significant delay between signalling times. As such, each sensor is attached to an individual microcontroller. While this increases the production costs for the prototype, it also increases the adaptability and improves robustness. Each additional board is still low cost and avoids excessive total cost. To power each device a USB type-B splitter was attached to a 2200 mAh power bank used for charging smartphones. The Arduino Nano can supply up to 40 mA per pin, so conservatively it will supply 120 mA per ultrasonic sensor for our use case, because the ultrasonic sensor uses 4 pins: VCC, TRIG, ECHO, and GND, of which the first 3 draw current at a maximum Arduino limit of 40 mA each. This battery can power a set of five sensors conservatively for about 3.6 h while fitting nicely in the pocket of a pant or jacket. This estimation does not currently include idling time nor any other optimisation.
In-ear-EEG – a portable platform for home monitoring
Published in Journal of Medical Engineering & Technology, 2020
In-ear-EEG hardware (Figure 3) include a chip set (in-ear-EEG Electronic) which performs hardware filtering, amplification and conversion to a digital form of analogue biosignals in the range of microvolts. The in-ear-EEG Electronic is connected with electrodes and with a portable computer (i.e., smartphone). Technical specification of the in-ear-EEG Electronic is presented in Table 1. Communication with the computer as well as a power supply for the electronics are realised over USB. The other side of the in-ear-EEG Electronic is connected with the in-ear-Electrodes using standard for conventionally EEG 1.5 mm connectors. The amplification and signal transformation in the Electronic (Figure 4) is based on an ADS1299 chip from Texas Instruments [17]. The Electronics consist of three main subcomponents (Figure 5): Low Pass Filter with user protection, amplifier with ADC converter and microcontroller board (MB). All components from the electrodes to the amplifier are analogue, whereas the amplifier output is digital. The microcontroller board provides power source of +5 and +3.3 V for all subcomponents of the Electronic block. The amplifier and ADC components communicate with the MB over the Serial Peripheral Interface (SPI) bus. To connect with a portable computer, the microcontroller board is equipped with a USB port for data transfer and to receive a 5 V power line from the computer. In our prototype an Arduino Nano V3.0 is used as microcontroller board.