Newbie requires getting started help for new project


#1

Hi,
I have a project (detailed below) and need relevant information to get started.
In particular, the most important for me is

Information about running system from 5V and charging a connected Lipo Battery (Can this be used to just back up the ram/clock and not run the device)?
What jumper settings are required to set this up?
Are there any Eagle PCB files for Hologram Dash available?
Does the device have RTC onboard or can it get current time/date from cloud and use battery backed system operation to keep clock up to date until cloud available to resynch time?

Details of what I want to achieve:
The devices will be installed onto vehicles.
Data records from another of our products will be received from the serial port
Each data record must be Date/time stamped and saved to SD card
If web cloud is available then all records are published and SD card file cleared
When vehicle is switched off, the system need to keep RTC running.

Thanks


#2

Hey @orbitcoms,

Your project sounds really cool. The Dash can run from a 5V pin and there is an RTC on the device. The onboard RTC syncs with cell-network-time when it first starts up and connects to the cell network.

You could connect the LiPo if the Dash is needed while the car is off, otherwise it is not needed to maintain the RTC. If you use the LiPo and want it to charge, just set the jumper to BATT like you normally would.


#3

Sounds like a very cool project! For what it’s worth, I show about a 12 mA load on the Dash when it is in deep sleep mode, which I believe is the lowest power consumption mode available. I recall that keeps the clock alive as well. That translates to about 166 hours using a 2000 mAh battery. Not too shabby!


#4

Thanks Michael,
I had 2 other questions I asked in an email but did not receive a response. Could you help me with these?

  1. Is there provision to store variable data locally on-board Hologram Flash? Or do I need to add external memory IC?
  2. Do you have an example how to send HTTP POST from Dash using Arduino code? I have set up a “Thingsboard” server and want to send data directly to it. The server is a REST API that accepts MQTT or HTTP POST (json).

#5

There’s no provision to store data in non-volatile memory. See this thread.


#6

Hey, Orbitcoms,

As @alano mentioned, there is no way to store EEPROM data directly in the Dash – the thread he cites is definitely your best bet.

I’ve had decent luck sending to Thingspeak via a Hologram webhook – data directly to the Hologram Cloud, and there’s a whole bunch of tools to manage it from there. You then have the great added benefit of being able to see it directly on the Hologram Dashboard from there (rather than having to debug the whole thing on your Thingsboard).

Here’s the thread that got me started: Routing Rules, Webhooks and HTTP POST