Modified Endplate for Fully Printable Eggbot
Derived from
Description
Finally, there's the "standoff" version, which places four tabs one side (either the outside of the left endplate, or the inside of the right endplate) to snap in a 1.8" x 2.5" that I soldered up to control the eggbot with a Modern Devices RBBB board instead of an Arduino.
You can see how I formatted the board and wired it up by examining the photos of the board layout and the hand-written wiring diagram.
The RBBB kits can be found at shop.moderndevice.com/products/rbbb-kit and the Pololu drivers can be found at pololu.com/catalog/product/1182.
Instructions
- **SpherebotEndplate-standoff.stl**: The reworked endplate, including four standoffs for snapping in a 1.8" x 2.5" custom circuit board (18 holes by 25 holes, or 17x24 usable)
- **Endplate_fixed.stl**: The original endplate design, but run through netfabb to clean up some rendering issues.
Actually, you can probably tell from the photo how it's wired up, but I just wanted to add a quick note about power: The USB provides power only for the RBBB, and there's a separate power socket for the motors. I didn't use the RBBB's onboard voltage regulator and power input, because it's 5V output is connected to the USB's 5V -- I opted for keeping all the motors on a separate input with it's own voltage regulator for the servo and drivers.
USB Cable
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Update: I bought the USB-TTL converter on ebay for $2.85, shipping included. The item was titled "USB 2.0 to UART TTL 6PIN Connector Module Serial Converter Buildin-in CP2102." It's a little red PCB with a USB plug at one end, and 6 pins on the other, with two of them jumpered together. The jumpered pins are TX and RX. (The diagram on the seller's page is incorrect.)
Using an old 4-conductor telephone cable and a couple of pin headers, I made a cable that connected TX, RX, 5V and GND to the appropriate pins on the RBBB. After installing the CP2102 driver, which Windows found online, I was up and printing without the use of the Modern Device USB BUB.
**Important Note**: There are several versions of this CP2102 USB-TTL converter on ebay. The one I got isn't the best one to get if you want to program a device (because the DTR pin isn't broken out), but it works just fine for standard serial communications.
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Hi , i am working on a copy of your nice design. Specially like the small rbbs board. I only miss an end stop in your design? Don't you use an ens stop or is it missing in the diagram?
Many thanks!
hi
can you help me?
i want to make this board and i need to pcb file that
Thanks for your nice comments. No, I don't use an end stop for this machine. There are plenty of pins left open on the RBBB, though, so it should be pretty easy to add.
How do you connect the USB to it given that the RBBB only has serial communication?
The cheap ebay converter works splendidly. Check the "USB Cable" section in instructions above for details.
I've been using the USB BUB that Modern Device also sells. I've ordered a $3 USB-TTL converter cable from ebay also -- that should also work if it's wired up properly, but I haven't tested it yet.
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Hey I really liked the compact electronics of this spherebot and so I built my own derivat. Just I used an Arduino Nano and made it even more compact :D
http://coolrobotprojects.blogs...
Awesome -- thanks for sharing your blog post!