Dart3- Buzzing on Analog Value Threshold
Alerts can be setup to monitor an assets external voltage and to send an alert when the voltage dips below certain level.
External Voltage is always reported on analogue input 2. So the below configuration means that an alert will be triggered when the external voltage of the asset is below 18V.
However this is not suitable for certain applications. E.g. if we want to monitor a secondary battery in a 4WD, and sound a buzzer in-cab to alert the driver when the battery voltage is below certain level.
The device firmware does not support buzzing based on analogue input, but making use of third party hardware like the LM393 Voltage Comparator Module can help achieve the desired result.
The Comparator can be set up such that it will then activate a device Digital Input - and the device firmware allows for buzzing when a DI is active.
Please see DART3 12-wire Harness Definition
The Dart3 has three digital inputs.
- Input 1 - Pink Wire
- Input 2 - Blue Wire
- Input 3* - Green Wire
*Input 3 is shared with the Driver ID line, so cannot be used alongside an RFID or Weigand reader.
Voltage Comparator Module
Please refer to the pinout diagram of the module you are using for this application to identify the Digital Output pin. Below is the LM393 comparator module diagram at the time of writing this article.
Input Voltage - 4.5 - 28 V
- Connect the digital output pin from the comparator module to either DI1 or DI2 in the Dart3
- Set the comparator up such that >2.2V will be on the Dart3 Digital Input when we are outside our allowable voltage.
- Connect the high side of the buzzer to the power source and low side to the switched ground, Pin 12- Yellow Wire in the Dart3
We assume the comparator module is connected to DI1 in the Dart3 for this example. Add the DI1 tab in OEM and set the following.
The Bias Resistor and active level can be left on defaults, ie
- Bias Resistor - Pull Up
- Active Level - Low
The "Buzz On" parameters determine the behaviour of the buzzer. By default, the "Buzz on Active Buzz Count" is disabled. This is the number of times the buzzer will buzz when DI1 is active. This can be set to any number of times. Setting this to 255 will leave the buzzer to sound continuously until DI 1 is inactive, i.e, when the voltage is above the predetermined level.
Telematics Guru Setup
Alongside the in cab feedback, alerts can also be setup based on the Digital Input. From the New Alert Advanced option in TG, configure the below
This means that an alert will also be sent to an assigned user when DI1 is active.