3D-Printed Circuit Board library (solder-free)
by CarryTheWhat, published
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The goal of this project is to enable the personal manufacturing of simple electronics, especially for Open Source Hardware -- with nothing except a 3D printer, your hands or equivalent, and the basic high-technology electronic components (capacitors, motors, transistors, etc -- but note that this will also include mass-produced microcontrollers and their shields!). Instead of solder, wires, and breadboards, OpenSCAD generates a peg-board PCB and component holder, and a circuit can be hand-wound together with conductive thread.
This code base is intended to replace conventional etched PCBs, initially for very simple applications. Included is a basic feature set, described in the Instructions. The pictures and uploaded STL files are for a simple circuit which demonstrates these features: a battery holder (I used 3 watch batteries instead of AAs to quickly and easily step up the voltage and save plastic and time), a momentary push-button, a toggle switch, and an LED holder.
So far I have printed a proof-of-concept on my Up! (pp3dp), and I've found best results with this type of conductive thread:
Check out the instructions for details and next steps.
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- peg: basic structure for winding thread, articulating circuit paths, and as end-stops for the thread.
- battery_holder: I've implemented this for AA and for a stack of 3 watch batteries. A sphere is at either end holding them in place, with holes and grooves for winding thread to contact the batteries when inserted.
- LED_holder (and similarly, resistor_holder): 2 sets of pegs are spaced apart, such that when each set is wound together, an LED (or other two-terminal component) can be inserted over the thread but under a latch. The result is a firm connection to the circuit.
- push_button: very simple momentary switch; 2 sets of pegs, one diagonal at a lower plane than the other such that if you thread the upper together and the lower together they will cross, but with a gap. If you push on the X, the threads touch and the circuit is completed.
- SPST_slide_switch: simple slide switch (don't forget to print the 'toggle' separately!). There are two pegs with a slot in between. After threading and wrapping the toggle for the switch with conductive thread, it can be inserted into the slot and wrapped to the back peg. When you slide this toggle forward, it makes a connection with the forward peg.
- I've tried only a couple different types of conductive thread -- not all are effective. One type (Inventables purchase) had only part of the thread conductive with the rest being structural, and gave lots of problems. Additionally, the resistance per cm adds up pretty quickly -- http://www.sparkfun.com/products/10118 This thread however has been best so far. 9 Ohms per linear foot is pretty negligible, and the whole of the thread is conductive. However, it has a tendency to fray, which might be a problem..
- Applications with high voltage or high current are not advised, as all connections are unshielded
- I know high frequency applications will also cause problems going forward, and I haven't yet tried to run a signal over connections
- github if there is interest in helping me!
- Apply basic feature set to simple printable OSHW applications; a flashlight, a desk lamp, and try again with my light ring: http://www.thingiverse.com/thing:11904
- Verify print-ability on the MakerBots, RepRaps, etc (let me know!). Also tweaks to increase the ease of threading.
- Expand feature set to include more switches, including a clicky-clacky push button, and more basic electronics components such as transistors, 8-pin ICs, and 9V battery connector.