I am currently working on my first two electronics projects. I will need them both to operate without being connected to a computer and I would like to be able to use battery packs or mains supply to power them (depending on where the projects are being used). Are there any PiicoDev modules that can be added to the projects to easily switch between battery and mains power?
Could you please also let me know the power needs of the following components and the best way to power the two projects (below)?
Project 1 uses a Rasberry Pi Pico, a PiicoDev LiPo Expansion Board and 4 PiicoDev RFID Modules. These will be connected to a 5V relay that will be connected to a 12V Maglock (with its own power supply connected to the relay via a Female DC Barrel Jack Adapter).
Project 2 uses a Raspberry Pi Pico, a PiicoDev LiPo Expansion Board, a PiicoDev Ultrasonic Rangefinder, a 4 channel PiicoDev Servo Driver (4 Channel) and 4 FS90 servos. Would it be best to have the servos and the driver on their own power supply and if so, what would be the best option?
Thanks in advance for any advice that you can offer!
Welcome to the forums!
Sounds like a great project. One thing I can see being a problem would be using the 12V system alongside the 5V system, if you are looking at making it portable, what would you be looking at to power the Maglock through the relay?
The same issue goes with the servo motor driver, it would likely need a separate power supply, due to how much current the servos require, it is not going to be easy to get that as a portable system. You would need to figure out the exact requirements of the servos and find a suitable supply that can provide enough current. Though it does depend on their use case.
Thanks for the reply mate! I would be looking at powering the 12V Maglock through an A2 12V battery or through a 12V portable power bank. Could I look at powering the 5V system with 4 AA batteries or is that not advisable?
Could you point me to any resources to figure out the current requirements for the servos or provide any suggestions for what would be suitable? I am looking at using the servos to either open / close a small plastic door or to lift a small plastic platform at an angle.
The battery functionality would be ideal, but it is optional. I should always have the option to run both projects through mains power - I was just hoping to avoid having more power cables than necessary!
Have a look at my Borg project
especially this section regarding power management
I realised early on that I would need a big PSU for the LEDs etc and would have an unfortunate set of voltage requirements, namely 12V, 5V, and 3V3.
Main power supply - a 12-volt Sealed Lead Acid (SLA) batteries (we are in the bush at a Scout camp - no mains power within cooee)
12 volts - from battery
Power amplifier for the audio
Input to a 12v - 5v Buck converter
5 volts - from the buck converter
3-watt RGB LEDs
High voltage side of a level converter for the LEDs
3.3 volts - from 3v3 output of Pico
MP3 player (so I can directly connect the UART data from the Pico)
Low voltage side of the level converter
Also, regarding the power, is the need to be able to connect the programmer Raspberry 3 to the Pico, while the big PSU is in use also. Without the smoke getting out of either one.
Solution: RTFM (https://datasheets.raspberrypi.com/pico/pico-datasheet.pdf - page Section 4.5 on page 19) and wire up the power to the Pico with a Schottky diode in line to the VSYS pin. And build in a good solid common earth point for everything to connect to.
Result: can safely power up from the battery, and can connect/disconnect the Raspberry Pi programmer, without disturbing the Pico (or killing the Raspberry Pi).
@Nathan243765 we recently posted a guide on Servos that includes a method for estimating how much torque your servo(s) will need and an overview of how to choose the right servo(s) for your torque/power requirements: Getting Started with Servos | Examples with Raspberry Pi Pico - Tutorial Australia
Have a look at the ‘How To Choose A Servo’ section.
Thanks for sharing your project Murray! It looked like a pretty awesome way for the Scouts to practice their Search and Recovery skills. I’ll have a look at the article and be in touch if I have any questions. Thanks mate!
Thanks for the link Jacob - I’ll make sure to check it out when figuring out the power requirements for the servos!