Using the AutoPi with an external power supply (LAB)

The device you have is pre-configured to work directly in your car. When working it in a lab environment you may need to supply the AutoPi with a controlled power supply. There is a couple of things you should be aware of, before connecting your device:

  1. Always power your AutoPi from the OBD connector. Don’t use the power inputs on the Raspberry Pi. This makes some of the function on the AutoPi not function correctly and could potentially damage your AutoPi device.

  2. The AutoPi has several commands that can be run from the local terminal. Use help to find them, like “power.status”. All terminal commands can also be run when logged in via ssh. All you need to do is add them to the autopi command, like “autopi power.status”.

  3. The AutoPi auto powers down when voltage is below 12.2V. This is to prevent draining the vehicle battery. Power it with 12.5V when in lab.

  4. here is a trigger (sleep timer) on the device, that will initiate if there is no COM to the car. You can see sleep timers by running this command “power.sleep_timer” and you can disable them by running “power.sleep_timer enable=false”.

We recommend getting the OBD power cable from our shop, to ease the connection to any external power supply. You can get it here:

https://shop.autopi.io/products/obd-ii-power-cable-8/

1 Like

Do we need to supply exactly 12.5V or can we supply more?

Having a hard time finding a configurable power adapter with exactly 12.5, most actually stop at 12V. I did find on that has 13.5V would that work? https://www.amazon.com/Belker-5V-15V-Universal-Adapter-Speaker/dp/B015H0UPWU/ref=sr_1_8?ie=UTF8&qid=1540916145&sr=8-8&keywords=multi+voltage+power+adapter

Hi @ziggyo7,

Yes this adapter will work. The AutoPi is able to handle 13.5V. Its should be safe up 15V.

best
Peter

Hi! Just received my AutoPi and the OBD power cable. I haven’t seen that kind of connector that is on the power cable. What is it called? What 12V transformer should I get to fit this connector?

Hi @sysdev,

The power cable is a standard DC connector in one end and then OBD connector in the other end. The DC connector fits in to most power supplies or power adapters. As such we dont have recommendations to the power adapter. Just make sure it can supply the needed requirements (above 1A and between 12-15V)

best
Peter

If you don’t have some older HW that has the correct connector and voltage, I recommend buying something like http://www.vanson.com.hk/product/smp-60wme/ so you can have use for it in different scenarios other then AutoPi later :slight_smile:

Br,
Mikael

1 Like

Thanks @Peter ! I have now bought a power adapter. So now on to next question :slight_smile: The connector on the power cable fell off (was very loosely tighten). Which one, brown or blue, is positive and which one is negative? I think the rasberry pi is sensitive to polarity.

Hi @sysdev,

Yes the power cable is indeed sensitive to polarity. I’ve attached an image with the correct connection:

Brown is positive.
Blue is negative.

best
Peter

2 Likes

Is there a command to disable the shutdown on voltage < 12.2 ? My PSU can only provide 12V.

Hi @Mikkel,

Welcome to the community.

In the advanced power settings in my.autopi.io, just set the Safety Cut-out and Battery Critical limit below that of your PSU. That should keep it awake. Also remember to clear your sleep_timers during startup, or change the sleep timers so the are sufficiently long to do your development.

Please notice, that when you change the setting for your development environment, the device could drain your car when inserted. So revert the changes before using it in your car.

best
Peter

Hi @Peter
Thanks that is good input. However the device doesn’t have enough time to connect to the my.autopi.iobefore it’s shut down. I only have around 30-60 seconds on the local.autopi.io to enter a command before it shuts down. Is there a CLI command I can use to set these settings?
Thank you,
Mikkel

Hi Mikkel,

If you just change it in the cloud, then the device will download the settings immidiately when its online (its the first thing it does). So it should work.

Alternatively, just insert it in your car and update the settings. Then re-insert it into your PSU after the settings been updated.

best
Peter

Great, will try that. Can you pls share exactly where I can find those settings in my.autopi.io. I don’t seem to find them anywhere. Many thanks.

You can find them here:

settings->dongles->advanced settings->power

The settings menu is found in the top right corner (the profile icon).

best
Peter

Having the power.sleep_timer enable=false timer disabled, the low power shutdown will still work?
Or how can I keep the autopi started (for defined period of time) after I turn off the engine?

Thanks

Hi @schrapnel,

If you disable all the sleep timers, then the device won’t go to sleep. If you want to control the sleep timer after the engine turns of, then you need to look at the “Event Driven” sleep timers under the advanced power settings. The “Period” settings will control, when the device sleeps after the sleep event has occurred.

Best
Peter

1 Like

Hi!

I am having a bit of trouble getting the device to start using the power cable (https://shop.autopi.io/products/obd-ii-power-cable-8/). I’ve tried supplying it with both 13.5V and 15V but it won’t start (IE, it does not show up as an WiFi hotspot). The device starts fine when I plug it in my car so I would assume the device is not broken. What am I doing wrong?

Hi Oscar,

Through the holes in the top of the casing, you should be able to see a green light if the device is on. It can be a bit tricky to see. This will indicate sufficient power.

If you dont see this, then an idea could be to check that the power supply outputs enough power (amps). Find one that will give you minimum 2-3 A.

best
Peter

I’ve actually got two units with two different power supplys. One of them is rated at 2A and the other at 2.4A which should be enough? No green light from what I can see (I even tried taking the plastic cover off but could not see any green light).