This was a surprising useful video with no distracting music or suscribe bells. I had no idea that the pico provided a buck and boost convertor from VSYS power. Thanks for the video!
This wonderful YT channel made me want to tinker with RPI pico. Super content, very clearly shown, without disturbing music, very competent help in the comments section. An attempt to donate the money via PayPal was not possible and on YT without a credit card it doesn't work at all. A PayPal friends link would be helpful.
Thanks for your kind comments. I may look into other options in the future. For the moment I'm happy with subscribes and likes as they help me to grow the channel.
Great video - very well explained - exactly what I was looking for. One minor gripe is that the audio is not very clear. but regardless - thanks for making the video.
Nice Video. I'm currently investigating using a Pico from the 'bias voltage' from a camera audio input - this is use to power mics at 1.5-5v (but normally 3.3v)... Looks like it might work :-)
21:27 - irrespective of the voltage on the gate, internal diode of the mosfet is in wrong direction so mosfet will always allow voltage to pass ;-) I think the mosfet should be opposite direction here
The diode of the MOSFET is the internal body diode, which is a characteristic of the MOSFET. It could allow current to flow if the voltage of VSYS is lower than the alternative supply voltage minus the required voltage for the body diode to conduct. If the MOSFET was connected in the opposite direction then it could allow backfeeding from USB (via VSYS) to the secondary power supply which is was the circuit is designed to prevent.
Thanks for the very useful video. One question, though: You casually mention to use a Schottky diode. This is for the power supply, so a DC voltage. Then neither the higher switching speed nor the lower forward voltage drop of a Schottky diode seems to be important when using a 5V or even 3.3V external power supply. Wouldn't a regular 1N4148 or 1N4001 also be usable in such a situation?
I normally use a Schottky rectifier diode because of the low voltage drop. This means less power loss. Particularly when using a battery. It's not going to be much in the grand scheme of things, but even a little can help. Another potential benefit could be that if the voltage from the power source is greater than USB then that will be dominant, although if that is important a MOSFET would be a better option. A regular rectifier diode would work fine instead.
I'm using a Pico W in a project where I want it to be able to work (communicate) wirelessly or wired, is it safe to have some batteries (3 AAs) connected to VSYS and then also plug in to the USB port? Or in other words if I want to go from wireless to wired, do I need to take out the batteries or switch them off somehow before I plug in to USB?
Yes, just use a diode to prevent the USB power trying to charge the batteries. This is the circuit at 15.53 replacing the external power supply with your batteries.
Great vid mate, If possible, could you give some advice, I am looking to use the pico w in my car, What id like to do is power it from a 12V battery, That is the issue i have, i dont know how. The reason i want to use the pico W in my car is mainly as a way to.., press a button, power on, side lights of the car turn on for 30 seconds, power off. I have done the coding for the powr on, delay, power off, but i dont know how to power a 5V pico from a 12V battery, I wont be using the car battery, infact I will be using a 2nd battery I will be placing in the boot, i havent chosen yet if it will be a leisure battery or a car battery. I have other plans to make that battery multi purpose, such as connecting a convertor to power my airsoft batteries and a mini cooler. My end goal for the pico W is to bring a feature to my car that other cars have, such as pressing the key fob to unlock the car and the main lights turn on, i think its like a courtesy lights, sadly my interior light doesnt turn on with the unlock, it only turns on when opening the door, so other ways around my issue is impossible, but that is my intention, courtesy lights. other future ideas are of course, RGB within the car which, once i have a solution for the powering, ill be using my Pico WH for it. I have put a post on reddit but the moderators keep removing my post, i have tried posting on respberrypi and raspberry pi projects. not sure why but mods on both pages remove my posts about this.
@@elusive62 Although possible without, I would recommend keeping the two power supplies completely isolated from each other. Eg using relays or opto isolators.
I mean the two 12v supplies, the car and your electronics supply. You will also need to make sure all your signals to the Pico are only 3.3V and you increase the signal to be enough to drive whatever outputs you are using (eg relays). Or it may be possible to drive opto-isolators / optocouplers directly depending upon voltage and current requirements.
@@PenguinTutor the only part the wiring would come together would be at the sidelights, I did consider using the VCC as a signal for the pico to begin the timed "sidelights on" for 30 seconds, but i think it would be much more simpler to put a button i would press to begin the timer.
First thing: Which MOSFET should I use? Can you name one you would recommend the most? Second thing: I often see the diode in the opposite direction on the internet. Can you explain the thing with the diode a little bit more? In general: which components do I need to buy to best power my Pico (with and without W) with either 3.3 V or 5.0 V?
Do you mean the MOSFET used at 14:21 - used for switching a high power LED? If so then it depends upon the current requirement, a 2N7000 is good for up to 200mA, but for more than that you may need to look at one in a TO-220 package such as an IRLB8721. What do you mean by a diode in the opposite direction? Do you mean across the MOSFET (that may be showing the internal parasitic diode), or across the load which could be a flyback diode to protect against back EMF from inductive loads. To power a Pico I normally use a 1N5817 from a 5V supply to VSYS (pin 39) as shown in the VSYS diagram here: www.penguintutor.com/electronics/pico-power
Thanks for your fast reply! All my questions refer to the improved powering of the Pico itself you are showing in the picture in 21:20. I want to use a power supply made for breadboards, which can output either 3.3 V or 5.0 V. And I want to be able to connect the Pico to the PC at the time. From your video I understood, that I need to put a MOSFET and and diode infront of the pins of the Pico. But I don't know which ones exactly.
You can use the simpler diode based version which just takes whichever is the highest voltage. The diode projects against back feeding to either power supply. The MOSFET version has a lower voltage drop and disconnects the external supply when connected to USB if that is what you want. The datasheet suggests a MOSFET but I expect that is SMD. The main characteristic to look for is the maximum current, any P-channel MOSFET that can handle the required current should work.
I wounder if it would be possible to power the pico directly of the 3.3v pin assuming the onboard solution is turn off and the power source is a known good supply?
I can't see any reason why it wouldn't work, but considering you can just connect 3.3V to VSYS I don't see much benefit to doing so. There doesn't appear to be anything that uses the VSYS supply, except as an output on the connector and as a voltage reference for ADC3 (so you can read the input voltage). I don't know how the RT6150B-33GQW will respond to having power at the output, but not at the input, but it would probably be okay especially as the enable pin won't be pulled-up. The only advantage I see to bypassing the onboard buck-boost convertor is a slight improvement in efficiency due to the loses there, but those will be fairly small.
Yes I do still recommend that you use a Schottky diode. If a voltage source is higher then the battery then it will try and charge the battery. This can be detrimental to the battery and in some circumstances dangerous. For a LiPo battery then you should be using a dedicated charging circuit. These are typically restricted current chargers designed to prevent the battery from overheating.
If you want to use the USB power supply to power your own circuits then you can use the output from pin 40, the VBUS pin. This is shown at 6:11 in the video.
@@PenguinTutor I want to power the pico through an external source. I want to use the usb cable to transfer data from and to the pico and my lap top. How do i make sure that the pico draws power only from the external source and not from the usb ?
@@santosalex213To guarantee that you'd need to create a custom USB cable without a +5v connection. If you use a Schottky diode to VSYS then as long as the external power supply is a higher voltage then that would be used in preference to USB.
Hi I did the same setup at 18:19 timeline in video. except the IN5817 i have used IN5819.. BUT the magic smoke appears when i plug the battery and usb both ...I fried my pico...a buck boost converter was attached with the lipo pack 5v. what is wrong here?
Was your buck boost providing the correct voltage? The absolute maximum Vin for the Pico's buck-boost is 6V. I have tried some buck-boost regulators in the past and they have provided a much higher voltage especially with a low load. It's best to test with a meter before connecting it to the supply. Other than that I can't see a reason for why it would do that. That is essentially the same circuit as provided in the Pico datasheet (page 19).
@@PenguinTutor Yes, XL6009 buck boost converter that I used in my setup. The output voltage set was 5.3V (tested via a multimeter yellow color model number DT830D). Another thing that I used IN5819 diode as a substitute on IN5817.
A question. Can I simply remove the buck converter from my circuit and use LiPo battery (with TP4056 1A charging module), keeping diode as in your circuit?
@@abhinavgolwalkar IN5819 should work fine as a substitute for IN5817 (higher voltage tolerance and slightly higher voltage drop). Generally the boards with a TP4056 are designed so that you use that to charge your battery, then physically disconnect it from the charger and connect the battery to your circuit. If you are looking to use as a UPS then you probably need a dedicated chip, perhaps the LTC4040 (I'm not familiar with that particular chip, just found on a quick Google, so you will need to check suitability). If you are just powering the Pico then you should be able to connect LiPo through a diode to the VSYS pin, as you can run from as low as 1.8V. Note that this will mean that you don't have any additional protection from your LiPo (some LiPo batteries have built in short circuit protection which I would recommend). Again page 19 of the datasheet covers this: datasheets.raspberrypi.com/pico/pico-datasheet.pdf " For example a single Lithium-Ion cell* (cell voltage ~3.0V to 4.2V) will work well"
What power supply are you using to VSYS? If it's 5V then you can use that. If not then you will need to use a separate 5V supply as the Pico does not provide any step-up voltage outputs. If using a 5V sensor then make sure the data signal is compatible with 3.3V on the GPIO pins.
@@PenguinTutor want to use a battery. Let me ask in this way, with the diode in between VSYS and VBUS will it be possible to power up the pico using a battery through pin VSYS but powering up external circuitry using VBUS, as in the case when using a USB power supply?
@@happymatekenya394 No. It's one way. You can power through USB / VBUS and then use VSYS to power other components, but if you can't use VBUS as an output unless you provide power through the USB port.
Do you have a 5V battery? In which case you could use that for VBUS or VSYS and also use that to power your 5V logic. If not then you will need external circuitry to increase the voltage to 5V - perhaps a buck-boost converter.
