This is a modified version of Decade Resistor Box by Brockas.
See their design for more details.
I moved the banana plug connectors to the side and modified the size slightly to account for that.
In my photos the 10k resistors are SMD and the 1R are missing for now, but it's more about the box than the decade :)
Cette semaine on tente d’imiter mon idôle Matthias Wandel en essayant de construire un engrange en bois…
I can’t sleep. Instead of sleeping, I’m hacking robots. Last year during my winter holiday I wired up a Raspberry Pi to my Roomba, to drive it around and such. More recently I got a Raspberry Pi Zero and wanted to do the same thing.
You may be asking “if you’ve already done it with a Raspberry Pi, are you really doing anything new?” The answer is “kind of.” In the previous version was an original Raspberry Pi Model B. I also used a USB-to-serial cable. This version upgrades to a Pi, and uses the onboard UART. So fewer components. Again, I used Jason Bradshaw’s excellent iRobot Node Library.
There were a couple of hiccups setting this all up:
The Raspberry Pi Zero operates at 3.3v. The Roomba’s serial lines operate at 5v. Fried Pie sounds amazing. Fried Pi sounds like an expensive tragedy ($5 Pi Zeros are cheap but super-unavailable) So I needed to put together a level shifter. I had an AdaFruit Level Shifter sitting around from several years ago, so I soldered that up. The Pi’s pins have 5v and 3.3v, so I was easily able to wire things up.
On my previous Roomba Pi project, I used a USB-to-Serial cable because it was a super simple solution. Trying to use the serial on the Pi wasn’t obvious. At first, I came across an article that said to use the standard Linux port
/dev/ttyS0. That failed – it turned out I didn’t have it. Exploring the
/dev directory I found the real port
/dev/ttyAMA0, but that didn’t work either. It turns out you have to prevent the operating system from taking it over. This is done in the Raspberry Pi config (
sudo raspi-config go to Advanced and then to Serial)
This is kind of dumb, but I couldn’t get it connecting correctly at first because the default in the library was 57600. The Roomba 500 series+ communicates at a default of 115200 bps. Simple fix, and I was off to the races.
Un petit épisode utile pour une fois, où comment utiliser les composant dynamiques ou dynamic components sous SketchUp…