How high can pull up/down resistances be? The value of a pull-up or pull-down resistor is limited by the leakage current of whatever it is pulling. For instance, say you have a 100K pull up resistor on a mosfet gate connection, and the mosfet has a gate leakage current specification of +-10uA. Your 100K resistor […]
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NMEA 2000
NMEA Docs They’re generally paid, however the following is available online: National-marine-electronics-association-nmea-2000-standard-for-serial-data-networking-of-marine-electronic-devices-main-document NMEA 2000 Basics 250kbps CAN Bus 29bit identifier (ISO11783 standard) 8 byte data field Open Source Libraries The NMEA2000 library by Timo Lappalainen basically makes NMEA2000 possible for the masses (it’s a big and complex standard!): https://github.com/ttlappalainen/NMEA2000
HC-06 Bluetooth module
Most general info is as for the HC-05 – see our page here. HC-05 vs HC-06 The HC-06 is a 4 pin slave on only variant, whereas the HC-05 can be configured to be a master or slave Bluetooth device. Parts HC-06 Bluetooth Serial Transceiver, you want the HC-06 that is mounted to the 4 […]
HC-06 Configuration
The HC-06 is the slave only version of the HC-05. It can also be configured using AT commands. Config settings The config settings are non-volatile (they are remembered when power is lost). Sending config commands to the HC-06 using a PC using a USB to serial cable You might want to do this so you […]
HC-05 transparent link
Transparent link using two HC-05’s Configure one as the slave, by following the instructions on our other page over here. Configure the other as master, using these config commands: Return the HC05 to its default manufacture settings (hold button when sending): AT+ORGL\r\n Set role to Master: AT+ROLE=1\r\n Change comms settings: AT+UART=115200,0,0\r\n Changes the baud rate […]
HC-05 Configuration
Config settings The config settings are non-volatile (they are remembered when power is lost). Sending config commands to the HC-05 using a PC using a USB to serial cable You might want to do this so you can configure the HC-05 without using an Arduino, or even if you want to connect your computer to […]
Instrumentation Amplifiers
Level shifting of the op-amp output You can use instrumentation amplifiers that include a reference input, which is used to level shift the output based on reference voltage of your choosing. Example devices: AD8420AD8421
Creating a new 0V rail within your unipolar power supply
Say you have a 0V and 24V power input, but you need a bipolar power supply, or maybe a part of your circuitry powered with its 0V offset from the power input 0V? Using linear voltage regulators You can use voltage regulators to create voltage rails wherever you like within your power input voltage range. […]
Simulating a load cell
Potentiometer and resistor A pot and a resistor can be used as a really simple way of simulating a load cell. Take the following example: 2.5v excitation voltage2mV per volt at full range.2.5v excitation x 2mV per volt means it will output 5mV at full load. A typical 4 pin loadcell connection:1 – 0V2 – […]
Excitation voltage
A load cell datasheet will typically specify an excitation voltage, for example 10 Volts. This implies that you need to run the device at 10V, but that is not the case. It is the ratio of the input voltage to the output voltage that is all-important, and you can use the load cell at lower […]