3.3V Is Not Enough For This Raspberry Pi Zero

A Raspberry Pi Zero is down to a price and size where it’s just begging to be integrated into your projects. Unless, that is, if your project involves a lot of 5 V equipment. Then it’s just begging to be fried.

[David Brown] solved this problem by breaking out pins with level converters. He used flat-flex cable and some pin-headers. While he was at it, he added a full-sized USB port and power headers. (Extra hack points are awarded for connecting the USB to the board through pogo pins.)

The board is now in its third revision, having sacrificed a Pi Zero and learned why many boards include over-voltage protection in version 2.0. It’s a neat and tidy solution to the problem of interfacing the Pi with a non-3.3 V world.

We saw a ton of Pi Zero add-ons when it was new. No doubt some of this was due to our Pi Zero Contest, but we bet a lot of it was also driven by need: the need for VGA out, or quadcopter control, or just lighting up power-hungry LEDs. You Pi Zero is only as versatile as you make it.

26 thoughts on “3.3V Is Not Enough For This Raspberry Pi Zero

  1. Only if you can find it less then $40 with shipping.
    Ive been ordering the Orange PI now. And they been great for what Ive been using them for.
    And a hole lot cheaper with shipping.

      1. Yeah, I have gotten several from Adafruit over the last few months for various projects. Just sign up for the “In Stock” notification and keep an eye on your email :)

  2. Adafruit has Zero shipping starting at $4.95. Almost 100% of cost but that’s more a function of how cheap the Zero is. I’ve bought 2 from Adafruit at separate times and both arrived safely and promptly.

    1. That’s reasonable if you live in the US. Adafruit isn’t pushing the envelope with their international shipping rates. I’ll believe the Zero is a thing when you can order it from AliExpress for something close to MSRP, shipped. Like you can with the 3.

      1. “I’ll believe the Zero is a thing when you can order it from AliExpress…”

        Are you seriously saying that you don’t believe it exists because you haven’t had an opportunity to order it? I’m going to play it safe and assume that English is not your first language, because otherwise you’re either stupid or a troll (or both).

        That, or I’m imagining the Pi Zero that is sitting right in front of me, underneath my monitor, as are all the project builders on this site and others who have been using the Pi Zero in their builds for months.

        1. Are you seriously trying to convince him in the superiority if your English language skills after interpreting the phrase “is a thing” as “does not exist”?
          I bought a Pi Zero from Adafruit a few months ago, but I also got a Pi 3 to justify the $5 shipping charge. Until they lift the 1-per-order limit it will remain a “loss-leader” for Adafruit and all other distributors – a way to get you to buy other, much more expensive items. For me the Pi Zero is just a curiosity to show to my not so technically inclined friends. Until someone starts selling 5-packs with $5 shipping I will base my projects on something else (the NanoPi for example).

        1. Quicker is your problem, not mine. For a $5 board, ordering a few in advance with slow, cheap shipping is perfectly reasonable in my books. That’s how I stock most of my lower value parts. Of course, that’s only a valid approach if you can actually buy them with reasonable shipping costs, and one per order from Adafruit is not that.

    2. As a whole they actually don’t. Only if you live in one of the few areas they allow USPS shipping or maybe really close to their facility. For the rest of us inferior customers, we have to pay full UPS Ground rates. It costs me $13 to buy a $5 Pi Zero. If you live on the West Coast you will have to pay close to $18. They refuse to offer any cheaper shipping methods for many places in the US because supposedly USPS loses too many packages. I have ordered literally several hundred packages over the last 12 months via USPS and not a single one was lost or delayed. Sounds to me like an Adafruit problem but don’t bother complaining or offering suggestions as they won’t listen.

      1. In fairness I’ve shipped some stuff up there and unless your using DHL, the prices are astronomical compared to anywhere in the lower 48. Alaska, PR ,AS, and Hawaii are usually losses in shipping for most companies who don’t want to exclude you in the small print.

  3. A 3.3V OUTPUT can almost always drive a 5V INPUT fine – anything above about 2.5V is seen as a “logic high”.

    A 5V OUTPUT can’t drive a 3.3V INPUT without risking frying it, but a simple pair of resistors for a voltage-divider work fine, in theory about 2:1 ratio but in practice two equal-value resistors, OutputInputGND will be providing a 2.5V logic level, and your 3.3V input will be triggering at around 1.7.

    1. 3VCMOS output can safely drive a 5VTTL input.

      Other than 74HC(vs HCT) parts, It’s not entirely clear what parts are 5VCMOS and what are 5VTTL. My only personal experience is with people shoehorning 3VCMOS parts into the SNES (which is definitely 5VCMOS): there random logic high will be read as 0 with very low probability, but enough to crash a game.

  4. I would use proper level shifters. I don’t see the advantage of using discrete parts as if you dparts counto more than a couple the parts count goes up quickly. It is also vaguely reminiscent people driving RS232 lines and taking RS232 inputs on their Commodore 64’s 5 volt RS232 with diodes and resistors. Back before the Maxim chips were on the scene. I did not do it, but I knew people who did. If you did not mind unreliable sending and a really good chance of cooking the 6522 VIA you could get away with it for a while.

    I tend to save the level of hacks for stranded on a desert island situations though. I like my designs to work reliably and without over stressing any of the parts.

  5. I feel for international customers. But the shipping to various countries here is still less than shipping for the proposed CHIP computer. A $3 computer but over $20 shipping to the UK. We still have the limit 1 per customer over here too, it’s not just Adafruit. That limit will eventually be lifted, probably with very reasonable shipping rates! I realty don’t think they were expecting the demand to be so high. Just be a little more patient. They’re already into revision 2 with the camera socket. The Pi is only 4 years old, what will they create in the next 4 (for the same price!)?!?

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