UPDATED to openNDS!
So... these Raspberry Pi0w's are quite addicting little IOT Devices (and they're really inexpensive!), but I grew tired of cobbling everything together each time. Let me introduce you to my Buster-IOT-Splash meta-release:
Gadget Ethernet [DHCP and fixed at 169.254.3.14] so even if you mess up networking, you can plug it into your laptop and be able to fix it.
HostAPD to provide a dedicated WiFi network (even over the same onboard ethernet). I use this with my MaslowCNC to have a reliable WiFi connection to my phone for controlling the router even if the upstream goes away. Default WiFi WPA2 password: raspberry
openNDS- With a bit of hosts magic so it can run offline as well. This way as soon as you connect to it, the device's webpage will appear (maybe in a security browser, but...)
Warning! Please secure this; if you install this, you have made a very open, very large access hole to your networks... luckily I have some instructions on the "openNDS" webpage that appears and SSH (default password) is enabled so you can fix them.
This is meant for makers, so I left the size at ~4GB (50% used); you can resize it using raspi-config. I also left a handy little script in sysprep/sysprep.sh (sudo that from its directory) that "cleans the system for shipping" (removes ssh keys, wpa_supplicant.conf, etc).
QuickPCB's are printed with a silver-bearing ink; for professional circuits, that means you need to keep a few things in mind:
There is *no* heatsink effect. The ink conducts heat very poorly.
The traces have resistance (like ohms of resistance -- see below). --For Logic, this will work. For sensors/power, you need to check to see if it works--
There is little/no wetting effect of solder; if you're not happy with the resistance of a trace, you'll need to fabricate a piece of wire to lay on top of the trace -- just tinning it won't do.
The adhesion of the "ink" is very poor at high temperatures; if you're jumpering something or soldering a wire to the board, it's best to solder to a component lead (the larger the better; 1210 packages are good, 0805 is marginal and 0603 will just give up with any kind of tension).
The "ink" is not quite flat either and it's all conductive; a 1206 package makes a good jumper for 1 trace (not two), and an 0805 package is hit or miss.
Soldering is more like "leading" of a stained glass -- you have to draw your iron across it to wet an area. Remember to use a low-temp solder and a temperature-controlled iron.
Also remember that the solder will try to pull the silver from the "ink" so keep the iron on for just 1-3 seconds per joint.
The R_Check board
I printed the R_Check board to give a real-world gauge of resistance (yes the "ink" does have specs, but toying with Ohms/mm is kind of like working with board feet of lumber); from my testing:
0.010" traces have 1.13 Ohms/inch
0.012" traces are about the same
0.024" traces are 0.50 Ohms/inch
If you tin them:
0.010 / 0.012" traces didn't change much (I got ~1.05 Ohms/inch)
0.024" traces dropped to 0.39 Ohms/inch (0.30 if you re-tin by hand)
I did the tinning as part of the paste-solder-reflow (I can put parts on the board and send you completed boards, but that's going to cost more than $20 -- and the solder paste has a "stencil time" of 2 hours, so shipping a pasted board won't work very well). I then re-tinned with an iron to "spread the solder by hand."
Need to use a temperature controlled iron (ideally, use Sn62 alloy @ 215c / 420F)
I can get you PCB's in 2-3 days (you send the file and PayPal the money, I drop the boards in USPS post as soon as they're done) -- faster if you're in the Atlanta area, especially if you get me the files before noon!
$20/1, $30/2 and $40/3
Send your inquiry to , and I'll get it shipped to you quickly.
Initial Hello World PCB (a 555 timer blinking some LEDs):
I've been impressed with Robo3D. They've sent me replacement parts, and my "out-of-the-box" experience required only minor tweaks, so I went for the "Kit Option" for my 2nd printer.
My CobbleBot Vanguard, IMHO, is unfinished. There were no/missing instructions for:
Putting the guide wheels together (you needed to add some spacers or the bearings wouldn't function properly)
Breaking in the Z Ballscrew
Aligning the Z Axis so it doesn't bind
Routing the wires (and with 2 extruders, neatness counts...)
Mounting the extruders (the supplied Teflon tubing wouldn't let me put them in the "obvious spot").
Proper home-switch mounting
Mounting the heated bed (thank you Mac Quillian)
Calibrating the stepper motor drivers
And so far, operation has been challenging:
Adjusting the Z0 height (Robo3D had an adjustment screw; now it has autolevel)
Since only one side is driven in Z, there is considerable droop across the X axis.
CobbleBot seriously underestimated the required power supply. 10A may be fine without a heated bed, but with the heated bed, you need >16A (the bed draws a little over 10A on its own!). I'm now using an ATX power supply with 24A capacity.
A lot of people are worried about contaminating the bearings and bushings if they use hairspray; I decided to use a removable plate of glass to not worry about the issue:
Glass plate held in with binder clips. Sorry about the filament bits!
Go to Lowes (since Home Depot won't cut glass) and get a 10x12" piece of glass. Have them trim it to 10x10 (unless you want to drill holes in it for the bed bolts to go through it. Better yet, get 2 or 3 so you can have 1 "ready" for easy swapping.
Cut a notch in the front-left leg so you can have the full range of motion without hitting a micro-binder-clip
Apply hairspray/abs juice/etc to the plate of glass while it is not in your printer. Wait for it to dry.
Secure it to your printer with 3 binder clips. Be sure it's flat on the bed with nothing between the bed and the glass.
Adjust Z height if you don't have autolevel.
Now you can print with hairspray without worrying about it contaminating your bearings!
Or at least 2D printed ones: https://www.youtube.com/watch?v=IANBoybVApQ
Go to 5:40 to start seeing demonstrations -- a magnetic spring (where attraction and repulsion cancel each other out to make a stable point), and a catch that latches when you rotate!