Lego quadruped Arduino? (glowy)

[glowytheglowbug]

8 hours ago, oracid said:

The DC power (link above) is very cheap and you can directly power your Arduino Uno with which it already contains a voltage regulator.

The regulators and capacitors would cost more .

For some reason my servos arnt working properly and randomly go to extreme positions sometimes, still not sure what is the cause but it happens when using the battery or DC power

[oracid]

I guess your DC power is not with the good voltage.
As you can see in this two links, it is good that the DC power voltage is 12V.

Arduino Uno Rev3 — Arduino Official Store           Arduino Nano — Arduino Official Store

In addition, the Uno must be powered by its PC socket and the servos must not be powered directly by the Uno.
It is for these reasons that it is important to use a SHIELD.

[Ryokeen]

Could find anything about it, but remember the geek servos run with max 6V or more, they like to be used at 6V and i think the min workvoltage is 4.8V. Also they require quite some mA, up to 800 on stall and use a pwm signal

[oracid]

47 minutes ago, Ryokeen said:

Could find anything about it, but remember the geek servos run with max 6V or more, they like to be used at 6V and i think the min workvoltage is 4.8V. Also they require quite some mA, up to 800 on stall and use a pwm signal

I have used these servos very often in my projects. I invite you to refer to them.
As I already said above, you need an Arduino Nano, a shield and a 7.4V/8.5V (2S) battery.
Above you have all the links you need.

[glowytheglowbug]

I just bought four 18650 cells, two will be used in the project to power the arduino and servos, they have 3.7v and 3200mAh each, I also bought a battery holder to contain two cells in series and a raspberry pi (along with yet another arduino), I will be testing out controlling the full robot dog with one arduino first while I wait for my nano and shield to arrive. 

Is there a circuit to allow me to charge and drain the two 18650 cells while they're in the battery holder

eg something like this circuit but the AA's are 18650s and there's a charge/discharge circuit in between the batteries and the arduino (the batteries will be connected to the breadboard too)

[oracid]

- first of all, you must not make the charger yourself. 
- the usb cable must be only connected from a PC.
- you must not charge and use the battery simultaneously.
- in my opinion, to buy single 18650 bateries is not not a good idea.
- you can buy Li-ion battery but with the good charger.
- here the link for the Li-ion 2S (7.4V) and charger : https://fr.aliexpress.com/item/1005005465159863.html?spm=a2g0o.detail.1000014.11.2e68CAMrCAMrHH&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.40000.326746.0&scm_id=1007.40000.326746.0&scm-url=1007.40000.326746.0&pvid=77e76235-ad2d-4550-9a02-10b7ba83e9c3&_t=gps-id:pcDetailBottomMoreOtherSeller,scm-url:1007.40000.326746.0,pvid:77e76235-ad2d-4550-9a02-10b7ba83e9c3,tpp_buckets:668%232846%238109%23214&pdp_npi=4%40dis!EUR!4.89!2.94!!!5.23!!%40211b61a417011784313726401ee6bd!12000033192447594!rec!FR!871422066!

[glowytheglowbug]

4 hours ago, oracid said:

- first of all, you must not make the charger yourself. 
- the usb cable must be only connected from a PC.
- you must not charge and use the battery simultaneously.
- in my opinion, to buy single 18650 bateries is not not a good idea.
- you can buy Li-ion battery but with the good charger.
- here the link for the Li-ion 2S (7.4V) and charger : https://fr.aliexpress.com/item/1005005465159863.html?spm=a2g0o.detail.1000014.11.2e68CAMrCAMrHH&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.40000.326746.0&scm_id=1007.40000.326746.0&scm-url=1007.40000.326746.0&pvid=77e76235-ad2d-4550-9a02-10b7ba83e9c3&_t=gps-id:pcDetailBottomMoreOtherSeller,scm-url:1007.40000.326746.0,pvid:77e76235-ad2d-4550-9a02-10b7ba83e9c3,tpp_buckets:668%232846%238109%23214&pdp_npi=4%40dis!EUR!4.89!2.94!!!5.23!!%40211b61a417011784313726401ee6bd!12000033192447594!rec!FR!871422066!

I think my diagram is a bit hard to read, basically i want to use my two 18650s without having to take them out and in of the battery holder and being able to charge them in the battery holder or connect them to the DC port of the Arduino, the usb port will be connected to the raspberry pi. The reason why i got 18650s is so that they seem to be pretty common and in case one or two die i can easily replace them, when i was searching for batteries, it seems like lion batteries are safer? compared to lipos. I dont need to charge and discharge the batteries simultaneously. also in my robot dog each leg can carry about 1kg and the frame itself is about 400 grams so i have a bit to play around. 

[oracid]

It is not good to use separate Li-ion batteries when could be high intensity. That is why in bikes or scooters they are soldered.
Of course you can charge the battery even if it is connected to the robot, but the robot must be off.
As you can see in the link, the battery has two connectors. The red one could stay always connected to the robot, and the white connector is for charging.

[Mikdun]

13 hours ago, oracid said:

It is not good to use separate Li-ion batteries when could be high intensity. That is why in bikes or scooters they are soldered.

In calls pack designed for high current (I guess this is what you mean by high intensity) they are actually welded, not soldered. Rechargeable batteries does not like high temperatures generated during welding.

13 hours ago, oracid said:

Of course you can charge the battery even if it is connected to the robot, but the robot must be off.

Why? I'm no expert but it does not seems critical. Charger will simply add it's current and reduce current flowing from battery. Or, if it has higher current than consumption the battery charging will be slower.

13 hours ago, oracid said:

As you can see in the link, the battery has two connectors. The red one could stay always connected to the robot, and the white connector is for charging.

I'm pretty sure they both join at the battery terminal. 

[oracid]

@Mikdun. Sorry for my English.
In absolute terms, your arguments are perfectly admissible, but @glowytheglowbug seems to be a beginner and I think it is better to use proven components and methods to avoid accumulating possible problems.

 

Edited November 29, 2023 by oracid

[Mikdun]

@oracid, no worries. Sure it's better to use proven components, I would do the same. Unless you want to dive deep into the subject it will be faster, cheaper and safer to use stock parts.

Just the point about not charging during usage got me curious.

[glowytheglowbug]

7 minutes ago, Mikdun said:

@oracid, no worries. Sure it's better to use proven components, I would do the same. Unless you want to dive deep into the subject it will be faster, cheaper and safer to use stock parts.

Just the point about not charging during usage got me curious.

ooh i was just thinking if there's  some circuit like this but for 2 cells 

 

[oracid]

2 hours ago, Mikdun said:

Just the point about not charging during usage got me curious.

If the battery is empty, you run on the charger.
I have a good quality battery charger. It recommends expressly to turn off use while charging.
Electronics is a complicated discipline. If the goal is learning it, then anything is possible.

If the goal is to make a quadruped with proven means, then I suggest simplicity.
A quadruped is already very complicated in itself, even if you have no problem with the electronics.

Edited November 30, 2023 by oracid

[glowytheglowbug]

On 11/30/2023 at 9:41 PM, oracid said:

If the battery is empty, you run on the charger.
I have a good quality battery charger. It recommends expressly to turn off use while charging.
Electronics is a complicated discipline. If the goal is learning it, then anything is possible.

If the goal is to make a quadruped with proven means, then I suggest simplicity.
A quadruped is already very complicated in itself, even if you have no problem with the electronics.

Allright, ive just talked to some people, seems like the circuit is wayyy too complicated to do
(There's no board that does all of that
But you can get a TP5100 2 cell series charger breakout board
And a latching switch breakout board to turn it on and off)

I have received both a https://www.keyestudio.com/products/keyestudio-raspberry-pi-pico-io-shield-development-board-for-raspberry-pi 
and a https://www.keyestudio.com/products/keyestudio-nano-shield-board-w-power-switch-for-arduino-nano

do you think I can use the raspberry pi pico shield? and what do I need to do to power geekservo motors as the voltage is low?

[oracid]

Yes, you can use a Pico as any microcontroller, but as I said above, the only real problem in creating a quadruped is not the electronics, but the functionalities of the quadruped and in particular, walking.

 

[glowytheglowbug]

37 minutes ago, oracid said:

Yes, you can use a Pico as any microcontroller, but as I said above, the only real problem in creating a quadruped is not the electronics, but the functionalities of the quadruped and in particular, walking.

 

apparently the output voltage for the pico is 3.3v/5v, do you think I need to do some kind of modification to power geekservos?
https://www.keyestudio.com/products/keyestudio-raspberry-pi-pico-io-shield-development-board-for-raspberry-pi
(also my arduino nano is taking forever to deliver and will probably arrive next year, so I'm stuck with the raspberry pi for a while)

 

also the raspberry version has these specs
 

• Power supply: 5V

• Output current: ≦500mA

• DC input voltage: 6.5-12V

• Output voltage: DC3.3V5V

• Recommended ambient temperature: -10°C ~ 50°C

• Size:45.339MM *83.617MM

• Spacing of pin headers: 2.54mm
  
  and since the servos draw 800mA at max is it still ok?

Edited December 13, 2023 by glowytheglowbug

[oracid]

If I trust this parameters it seems that the servo can work from 3.3V. But in my opinion this means that the signal of the servo can be from 3.3V

Anyway, you can't make a quadruped with only 3.3V servo voltage.

You have to wait for your Nano or order a new one from other shop. What the the seller says ?

 

[Doua]

Definitely do not use the 3.3v output from the microcontroller to power the servos. They will take in way more amps than the rated current on the pico output (you should be able to find the rated current on the pico spec sheet, usually its 20-100mA while servos can take 100s of mA each). 

You need to run the raw voltage from your batteries to a rail that can power your pico and your servos separately (in parallel). 

Edited December 13, 2023 by Doua

[glowytheglowbug]

5 hours ago, oracid said:

If I trust this parameters it seems that the servo can work from 3.3V. But in my opinion this means that the signal of the servo can be from 3.3V

Anyway, you can't make a quadruped with only 3.3V servo voltage.

You have to wait for your Nano or order a new one from other shop. What the the seller says ?

 

arriving next year on the 23d of jan
the arduino shield has 1.5A but the pico shield has only 

• Output current: ≦500mA
  so im not sure if I can use it to power stuff 
  if I get tired of waiting I can go and buy an arduino manually 

 

 

2 hours ago, Doua said:

Definitely do not use the 3.3v output from the microcontroller to power the servos. They will take in way more amps than the rated current on the pico output (you should be able to find the rated current on the pico spec sheet, usually its 20-100mA while servos can take 100s of mA each). 

You need to run the raw voltage from your batteries to a rail that can power your pico and your servos separately (in parallel). 

yes, that's what the shield is for it has a separate plug to power the shield and the servos 

Edited December 13, 2023 by glowytheglowbug

[oracid]

2 hours ago, Doua said:

Definitely do not use the 3.3v output from the microcontroller to power the servos.

I understand what you mean, but here the voltage is not from the Pico but from the Shield power.

Anyway, I have found this Shield in a case of my cellar. I powered the Shield with 7.4V. And definitely, the voltage of the pins is 3.3V, which is not enough for a quadruped. 

If you can find an Arduino Nano in Singapore, I think it is the best  way. 

I don't understand, France is further away from China than Singapore. Waiting a month is very rare.

Edited December 13, 2023 by oracid

[glowytheglowbug]

1 hour ago, oracid said:

I understand what you mean, but here the voltage is not from the Pico but from the Shield power.

Anyway, I have found this Shield in a case of my cellar. I powered the Shield with 7.4V. And definitely, the voltage of the pins is 3.3V, which is not enough for a quadruped. 

If you can find an Arduino Nano in Singapore, I think it is the best  way. 

I don't understand, France is further away from China than Singapore. Waiting a month is very rare.

china problems i guess XD

my items arrived in about 1-2 weeks and for some reason these take a month more

[aFrInaTi0n]

Christmas period is generelly considered to be rough, becasue of the western world having the christmas and also chinese new year - so I consider Nov-Feb as a period where it can be expected to take naturally longer..

[oracid]

Estimated delivery date is for legal regulation. Most often we receive the package before.

[glowytheglowbug]

20 hours ago, oracid said:

I understand what you mean, but here the voltage is not from the Pico but from the Shield power.

Anyway, I have found this Shield in a case of my cellar. I powered the Shield with 7.4V. And definitely, the voltage of the pins is 3.3V, which is not enough for a quadruped. 

If you can find an Arduino Nano in Singapore, I think it is the best  way. 

I don't understand, France is further away from China than Singapore. Waiting a month is very rare.

Do you think the pico shield can be modified like the nano shield to make the voltage higher? eg soldering new regulators or capacitors (I don't know) and also increasing the output current to =<800 ma

Edited December 14, 2023 by glowytheglowbug

[oracid]

Unfortunately, I don't think so. The Raspberry world is designed for 3.3V. A large part of the pins are used for communication, UART, SPI, I2C. And all sensors are 3.3V.
This is part of the reason why I stay with the Arduino Uno or Nano.