DiddyBorg and UltraBorg power arrangements

Submitted by lars_the_bear on Thu, 02/04/2016 - 12:43

Forums:

Hi

I would like to use an UltraBorg with the DiddyBorg. The DiddyBorg runs on (essentially) 12V, but (if I understand correctly) the BattBorg module provides a 5V supply for the Pi. The UltraBorg runs (I think) on 5V.

So my question is -- can the 5V output of the BattBorg operate the Pi, UltraBorg, and at least one servomotor at the same time? Or would I need to consider more elaborate supply arrangements?

I guess the issues are whether the BattBorg 5V can supply enough current, and whether the servos or other stuff in the UltraBorg would pollute the Pi 5V supply.

Best wishes
Kevin

piborg's picture

piborg

Thu, 02/04/2016 - 13:16

While it is possible that the BattBorg could power a single servo and the Raspberry Pi at the same time, we do not really recommend it.

The main concern is that the 1.5 A limit of the BattBorg my not be enough for both, especially with Bluetooth or WiFi dongles attached to the USB.

It is also true that sudden movements from the servos can temporarily 'dip' the 5V output, which usually upsets the Raspberry Pi and causes it to reboot.

As long as the maximum current used by the Raspberry Pi, the servo motor, and any USB devices does not exceed 1.5 A it will probably work.
If the Raspberry Pi either resets or gets 'stuck' then it is likely that the BattBorg could not maintain a reliable enough 5V supply to keep the Raspberry Pi happy.

lars_the_bear

Thu, 02/04/2016 - 17:23

Thanks. So is a possible solution to run two separate BattBorgs from the same battery, and use one to power the Pi and the other the UltraBorg? Or to use a completely different step-down converter with a higher current rating?

12v-5v converters are dirt cheap on eBay, and this one even claims a 96% efficiency (hmm...)

http://www.ebay.co.uk/itm/DC-DC-Converter-Module-12V-To-5V-3A-15W-Duble-...

On the other hand, the BattBorg is not punishingly expensive, and I don't mind buying a second one if you think that is the way forward.

piborg's picture

piborg

Thu, 02/04/2016 - 17:40

It is possible to use two BattBorgs from the same battery, this would allow you to use a total of 1.5 A for the servos.

Since the servos are not as fussy about having an exact 5V like the Raspberry Pi any 5V converter or UBEC should be sufficient for powering the servos.
It may actually be better to use a converter like you have linked since they usually supply > 1.5 A, this will allow you to use larger servos either now or in the future.

If you use a second BattBorg, UBEC, or a converter there is a wiring layout for the power supplies shown here: Powering the servo 5V on UltraBorg
Note that the power connections on the PicoBorg Reverse are actually wrong in the diagram (swapped), everything else is correct though.

lars_the_bear

Thu, 02/04/2016 - 19:14

Ah, I didn't realize that the servos attached to the ultraborg could be powered separately from the logic. Is that what the "5V link" is to control?

From the diagram you linked, it seems that the BattBorg should be able to power both the Pi and the logic of the Ultraborg. Is that right?

I was mildly surprised to see that your diagram has the Pi powered by the i2c cable from the PiBorg Reverse. I've previously found Pi's to be rather fussy about the resistance of the 5V supply cables. Is that not your experience? Might just have been my crappy soldering, I guess...

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piborg

Fri, 02/05/2016 - 11:50

That is exactly what the 5V link is for.
With it attached the servos and sensors take their power from the Raspberry Pi's 5V pin.
With it removed the servos and sensors take their power from the external 5V source.

The logic on the UltraBorg is always powered from the 5V pin on the Raspberry Pi.
This is also true for the PicoBorg Reverse.

The biggest problem we have found with the 5V supply is how close it is to a true 5V.
Longer and smaller cables do give more resistance, we have seen problems with 5V going through many boards.
What does work well is to get some thicker cables between the boards.

From past experience the setup suggested seems to deliver 5V reliably enough.

cleric boomer

Fri, 03/04/2016 - 12:55

Hi PiBorg

Once again I am here asking potentially daft questions.

Just to confirm as I am out buying a new LiPo batter for the DiddyBorg Red.

I am looking at getting a 4S LiPo battery (tomorrow as we are travelling out that way). This is a 14.8v battery (stuck between a 3350mAh or 2500mAh versions). I know the greater the Ah, the longer it will run.

Main question is , Is a 4S at 14.8v (nominal) sufficient for the DiddyBorg Red?

I am assuming that I will have to get another battery for the supply for the sensors etc (SR-HC04 Ultrasonics and UltraBorg, plus what other sensors I need).
Or will a higher voltage battery and BattBorg (for 5v supplys) be a solution?

Cheers

Chris

piborg's picture

piborg

Fri, 03/04/2016 - 15:29

A 4S LiPo should work well with the Red Edition.

You will want to change the power settings section in the diddyRed scripts to a 14.8V input, 12V output:

# Power settings
voltageIn = 14.8       # Total battery voltage to the PicoBorg Reverse
voltageOut = 12.0      # Maximum motor voltage

You could use another BattBorg or a second battery with the 4S LiPo, either would work well.

owen

Sat, 12/31/2016 - 14:14

hi i have got a diidy bog and i wont to convert the batreys to a Battery Pack Power Bank and i know how to do it but i wont to know were yuo got your Battery Pack Power Bank from if u could could yuo let me know thta would be grat

thnks owen

cleric boomer

Mon, 03/07/2016 - 15:45

Thanks PiBorg

I am now the "proud" owner of a 4S LiPo battery. which is 14.8v 4250mAh.

Price made my eyes (and bank balance) water. But it should be the only battery I need, and hopefully will last a while due to the 4A capacity.

Thanks for the repily to the email too. Some food for thought. Especially as I have the extra panel, so I can make a Double Decker so to speak.

I need to have a look at the layout etc.

Some of the questions have sparked un-healthly DiddyBorg based thoughts.

I was thinking of an optical distance sensor (patterned inner wheel and a LED/detector), but now a hall style sensor. I don't know...

Whats this along with a cliff/ledge sensor, the battery "Fuel Gauge".
Nevermind the sensors I wanted to mount (air quality)...

I think I need to take a breath and sit back and learn some Python programming. Can anyone recommend a good book for a 50 year old learner.......

Thanks again

Cheers

Chris

aliyulo@gmail.com

Fri, 05/20/2016 - 22:34

Hi Chris,

I was also thinking of putting in a 4s lipo battery to a battborg on a picoborg instead of 12xaa nimh. Just wondering, how long did your Diddyborg Red with 12v motors run with your 14.8v 4250mAh lipo before it died?
What gave out first the Pi or the Motor?
Were you able to install the distance sensor on a ultraborg and run on the same lipo?

Would like to hear on how your project goes cause im doing something similar.

Angel

cleric boomer

Sun, 05/22/2016 - 10:27

Hi Angel

Unfortunately real life has got in the way recently.

So I haven't had time to do much work on the conversion, I have done the work on the battery connections.

I have moved the reverse board from underneath to above the panel. Completed the wiring from the terminal block via a fuse, as recommended by Lars the bear and PiBorg.

To finalise that part I need to wire the connector to the terminal block, then the wiring for the new power supply is complete. Not much needs doing.

I have the ultrasound sensor (SR04), and a PIR sensor which I plan to fit.

I know the main problem for me will be the programming and getting the Diddyborg to act autonomously and drive around taking measurements.

I keep you informed, and do some photos.

aliyulo@gmail.com

Mon, 05/23/2016 - 23:56

Hi Cleric,

Thanks for the reply.

Im also planning to do a distance sensor on my robot and the waveshare IR camera with leds. Hope the 1.5amp power to my raspberry pi 3 will be enough to handel all of that.

What was the fuse that you used?

cleric boomer

Fri, 05/27/2016 - 09:10

Hi Angel

I used a 10amp glass fuse from Maplins, along with an in-line holder.

Just wired from the battery terminal block to the PiBorg Reverse/Battery Borg as usual (if using the 12AA pack)

Its been a busy few weeks, real life has really been there.

http://www.maplin.co.uk/p/in-line-fuse-holder-20mm-rc71n

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