Fighting the Pico Jumbo

[bablokb]

I recently received a Pico Jumbo as a present from a friend, and I was thinking about what I could do with it. So here are some thoughts and suggestions. Feel free to add your own ideas.

The first thing I noticed is that the Jumbo has about the size of a standard breadboard. Since these breadboards usually have a self-adhesive tape, I could just glue it to the Jumbo. But that would be just too simple so I was looking for a more over-engineered solution 🤔️ that would be somewhat on par with the Jumbo itself 😂️. And I also did not want to have something permanent, since chances are high that there are better ideas around.

So I designed a clamp that prints in about 10 minutes and holds the breadboard in place (the screws you see in the image aren’t really necessary):

The drawback is of course that it blocks a number of holes, but I think I can live with that.

Another idea was to use an Adafruit-Swirly type holder:

Note that the Adafruit Swirly itself wont work, since it requires M2.5 screws. But for the Jumbo, you need M3 (ok, M2.5 might work, but I have not tested it). The Swirly in the image above is a modified version with M3 compatible slots. Not optimal yet, I might add a solid boarder with holes lining up with the holes on the Jumbo.

Connecting wires to the Jumbo is also a problem. Crocodile clips are the first option, but I don’t really like them because they don’t make a sufficiently stable contact. Cable posts would be ideal, but the smallest I could find need 4mm holes, and the Jumbo only has 3mm.

As an alternative, I use M3 standoffs below and above the Jumbo and use fork-type cable connectors:

If you buy the correct size, you can make a stable connection - the M3 standoff will hold it in place.

Added bonus: you don’t need special crimping tools. Just take off the plastic of a normal DuPont-jumper and press the connector with pliers (right side). Or cut a wire, remove some of the insulation, bend the blank wire around and crimp it (left side).

As a tip: use higher standoffs for GND and lower standoffs otherwise. This will prevent shorts if you put the Jumbo an something conductive on your desk.

[alphanumeric]

I just received my free Jumbo with my last order. It’s sitting on my desk as inspiration to “what’s next”. =)
If I think / come up with something I will post it here. ;)

[bablokb]

Here is a fully working example:

Lessons learned: use longer jumper-wires 🤔️ It turned out that I underestimated the needed length.

[alphanumeric]

I’m thinking of doing something similar, but removing the two power / ground side rails on the solderless breadboard. Doing that will let you see the pin numbers on the Jumbo. Not a big deal but it’s what I’m looking to do. If you go with the half size 30 pin grid one it should fit on the Pico side of the Jumbo. Either way I’ll be sticking mine down. Just my personal choice. ;)

[bablokb]

Good point. I just checked: removing a single power/GND rail is already enough. If you can live with a certain asymmetry you can see the pin numbers and have a power/GND rail (which I think is very useful on a breadboard).

I am also thinking about giving these modern two-sided tapes a try. They claim that they can be removed without residues. Now that I have a second Jumbo (giveaway from the last sale) I have more options to experiment with.

[alphanumeric]

I like using the 3M stuff. The ones with the pull tabs for easy removal are handy for temporary stuff like seasonal decorations. And coincidentally pi and pico stuff. If I like where things are I just cut the tab off. All you have to do is get hold of a corner and its still pull able to remove.

[bablokb]

It turns out that the wireless-pack is not a good match for the Pico-Jumbo. The ESP32 on the wireless-pack is very picky about the correct voltage. Directly attached to a Pico it works fine, but via cables and a breadboard the voltage level slightly drops causing regular brownouts.

Current draw is probably not the problem. The datasheet of the ESP32 will tell you that it expects a VDD of 500mA. The regulator on the Pico/Pico2 will provide a maximum of 800mA, but the recommendation is to keep the load less than 300mA. That should be ok since the typical peak current of the ESP32 is in the range 250-300mA.

[alphanumeric]

Yeah I’m leaning towards using an RM2

RM2 Wireless & Bluetooth Breakout (SP/CE)

I already have a little Green Solderless Breadboard attached.
Breadboard (Mini)

which is just big enough if I go with soldering male headers on the RM2.
I could also go with a cable / jumper option.
8 Pin JST-SH Cable (SP/CE)

[bablokb]

It will be interesting to see how this works out. Personally, I think the RM2 is far too expensive. But from a MicroPython perspective this is probably your only choice anyhow.

[bablokb]

Introducing the Pico-Jumbo-W

So I replaced the Pico Wireless-Pack with a D1-Mini-ESP32 (it is actually a cheap clone, since the original device from Lolin is no longer manufactured). This breakout uses the same chip as the Wireless-Pack, but has an on-board regulator. So I can feed VBUS and I have no problems with brownout. My example in the image just updates the internal rtc of the Pico2 and shows the current time on the Pico Display-Pack.

What you really gain with the Jumbo is that all the pins are spread out across the full width of the breadboard. With a Pico on the breadboard things get very crowded once you use a large number of pins. So the Jumbo turns out much more useful than I initially thought.