Lego compatible Raspberry Pi case with LEDs, Switch and Piezo Buzzer
I recently saw a Raspberry Pi case being sold by CPC which is compatible with Lego construction bricks and decided to get one. Just the sort of thing I’d been looking for in order to extend the experiments that I’d been working on.
In a very short time I’d built a Rasberry Pi selfie-camera with count-down and WiFi capability. Apache handles being able to access the photos remotely whilst ScratchGPIO manages the interfacing and triggering the camera.
Pressing the trigger button causes a gentle beep-beep-beep and flash from the red LED for a couple of seconds, followed by a green flash while the picture is taken.
The raspberry pi case easily handles the camera – it pushes onto two little pegs and the camera lens pokes through where a stud would normally be moulded. It’s so discrete that it wouldn’t be possible to guess it’s there unless known about.
Scratch Program for the selfie-cam
The programming bit goes around in a loop waiting for the switch to be pressed. When that happens, the camera goes through a loop flashing and beeping, then pulsing the green LED. ScratchGPIO allows a simple “Broadcast Photo” command which works with either a USB or Raspberry Pi camera module. If Apache is set up to allow access to the same folder, then those photos can be viewed remotely.
A quick video should appear here later…
Scratch program for the Missile Launcher
My son has had his eye on these things called “spring shooters” for a while… and so have I. I picked up a few from BrickLink and managed to incorporate them into a little experiment I wanted to try.
This little build uses four spring shooters and two servos controlled by the Raspberry Pi. The program, written in Scratch and interfaced using CympleCy’s ScratchGPIO7 allows rapid firing of the spring shooters by dislodging each in turn. The servo has been set to nudge the end of the dart and then return to the centre position so that the dart isn’t gripped by the actuator. This seems to work well, although I had a few problems with not initially allowing enough time for the servo to travel to its full extent.
The program allows control of the panning with the arrow keys, as well as individual control of the darts by pressing 1,2,3 or 4. Alternatively, press [f] – “fire!” for a rapid salvo directed at your target. I’ve also added a couple of warning LEDs to the base. Green is safe… and Red Flashing warns people to duck. The next step is to add a PIR sensor and let Scratch handle our security needs…
I’m sure that those with experience of OpenCV will use it to track targets and deal with them automatically.
Raspberry Pi, NOIR camera and home-hacked Infra-red light source.
I’ve used USB cameras with the Raspberry Pi in the past for capturing events – either in response to movement or as a timelapse. I also recently acquired a PI-NOIR camera which works really well with an infrared light source as a baby cam. I’ve installed tinyCAM on my Android phone so that I can use the camera as a baby monitor, but recently I came across “Raspicam” for Android. Looks interesting as it allows control of more functions.
Should be worth a try. I bought an infrared light source from that well-known auction site and it provides a powerful beam of invisible illumination which lights the whole room, especially if it’s bounced off the ceiling. It’s powered by a 12v wall-wart. I’ve encased it in a modified camping light case so that the PCB is a bit more robust. Plenty of hot glue holds the thing together nicely.
The Raspicam App is available on the Google Play store and is demonstrated on Mike Redrobe’s Youtube video.
I’m posting another project in my “dreaming” category – Bookmarked things that I’d like to have a go at in future. The hanging wall plotter looks amazing and was featured on the Raspberry Pi blog a while back.
The simplicity of this project is obvious – just two stepper motors and a pen-lift servo. It eliminates the hassle of x-y axis mechanisms and sliders, instead using two thin strings or something like fishing line.
Here, the complexity is hidden within the software. Plenty of trigonometry and Pythagoras at work.
Just a quick post today, but something seems to be happening in the Plastic Construction brick and Raspberry Pi world!
Within a space of two days, I received information about these two:
- Micrometal gear motor to Lego axle Adaptor which allows geared 6v motors to connect to Lego axles and wheels. I can see that this is going to result in a lot more Lego being automated by Raspberry Pi computers.
- The PiBlox case for the Raspberry Pi is the second surprise. This is, apparently, a Lego compatible Raspberry Pi case. It features slots in all of the right places. including space for a camera mount.
I can see that I’m going to have to get some! It would be interesting to see if a battery pack, motor driver and servo buffer could be fitted into a second PiBlox case allowing for an all-in-one design.
Lego Space base using two servos and LEDs.
Here’s a simple creation to illustrate the kind of things possible using the Lego interface I’ve built along with servos and LEDs.
I’ve put some kind of radar antenna on top of a large servo. Scratch can be easily programmed to make the servo sweep backwards and forwards, scanning for distant incoming spacecraft. I’ve put a green LED into the top of the radar which flashes constantly. The light projects down the transparent green antenna, making for quite an attractive show.
Getting into your spaceship is quite tricky given that the crew compartment is at the top. There’s a miniature servo connected to a lift arm. Pressing the Spacebar triggers a Scratch routine to lift the arm, wait enough time to transfer the crew and then lower to the ground.
I suppose the next step would be to add a flashing red LED to simulate thrusters along with sound effects played from Scratch.
Lego interface – a L298 H-bridge motor controller with a servo buffer board.
Here’s the current version of my Lego interface for the Raspberry Pi. It uses an L298 H-bridge motor controller (covered in a previous post) combined with another of my 74HC541 buffers to protect the Raspberry Pi when connecting LEDs and servos.
The whole thing runs from a 5v plug-top power supply which is adequate for driving the 4.5v Lego motors along with a bunch of servos.
There’s a bit of scope here for making the whole thing more compact but that’s another step once I’m happy with the design. I need to add input connections so that the Lego creations can be fully interactive.
It would be also interesting to see if I could make this into a Lego case, perhaps with a bunch of plates combined with 1 x 4 x 3 Panels.