This is the first Camera Axe shield, but it leverages the lessons learned from the previous four generations of Camera Axe hardware. The word “shield” describes a board that plugs into the Arduino board. Arduino is an popular and easy to use open-source electronics prototyping platform used by artists, designers, and hobbyists.
The standard Camera Axe 5, which will be released in the next few months, will have a lot of difficult to solder surface mount components. Because making a kit of the standard Camera Axe 5 wouldn’t be possible I started looking for different ways of doing a kit version. I decided to go with this Arduino shield idea. Some of the reasons are:
There are hundreds of thousands of people who have Arduino boards. In fact many people who got earlier versions of the Camera Axe mentioned that they already owned an Arduino board. Expanding the functionality of hardware people already own is something that appeals to me.
Since the very first version of the Camera Axe I’ve been using the open source Arduino software. I’m pretty sure this shield will cause a few more Arduino boards to be sold and I’m happy to send the Arduino people that buisness. It is true people can use the various Arduino clones out there and that’s cool too.
This design makes the Camera Axe shield less expensive and easier to assemble.
The both versions of the Camera Axe 5 will use 100% the same software and will both have the same capabilities. Because this design is focused at the DIY and maker communities I decided to not include a fancy case that previous iterations have had. I think this is fine for most of these people since many of them are mostly concerned about functionality and cost.
Here are some improvements this design has over the Camera Axe 4:
Lower cost than the Camera Axe 4 kit.
Sensor ports can now have two data lines per port. This will be required by some future sensor designs. This was done while keeping backwards compatibility with all the existing Camera Axe sensors.
Adding input/output protection on the sensor ports.
Easier to load programs since you can use a standard USB cable to reprogram the Arduino boards.
The trigger LEDs are now multi-color LEDs so you can see the difference between triggering the shutter, focus, or both.
New timing crystal give much more accurate and precise timing.
After six months of work, the fourth version of the Camera Axe is finally ready. For those new to the Camera Axe it’s a programmable camera and flash trigger with two sensor plugs that can be used for a wide range of sensors. It can do anything from timelapse to photographing a shooting bullet. For a little background information read about versions 1 and 3 of the Camera Axe. This version is open sourced under the Creative Commons Attribution NonCommercial 3.0 License. I do sell kits, assembled versions, and various sensors at my store.
Camera Axe Video:
Here is a list of improvements from version 3 to version 4 of the Camera Axe.
The screen is much larger and this makes the menuing system easier to use.
The case is is much nicer because I had custom cases made for this project.
Added two LEDs to indicate when the camera or flash is being triggered.
Much nicer 3.5mm jacks for the sensors and camera/flash plugs.
Added a dedicated external power plug for those wanting to use external power.
The buttons feel much nicer.
Batteries last four times longer.
A new microcontroller that has two times the space for more features in the future.
The software is a complete rewrite and has too many improvements to list, but I’ll mention the greatly improved intervalometer mode and the new fast trigger mode.
The kits are easier to assemble (no wires or drilling needed).
There’s more information information about sensors, reprogramming, flash/camera cables, and much more at www.CameraAxe.com.
The major improvements are a new 3 PCB design, which makes this much more durable than the previous version. The other huge improvement is using the Honeywell SD5600 Optoschmitt Detector which has a fall time of 15 ns. Previously I was using a standard photo transistor which had a response time of 15 us. This new design is 1000x faster! This actually matters on faster bullets since sometimes the old sensor wouldn’t notice a fast small bullet. The SD5600 never misses.
The only downside to this new design is that it’s a little more expensive. Here’s the BOM.
This sensor has two IR sensors spaced exactly two inches apart. The user inputs the distance from the sensor to the desired position of the projectile when the picture is taken. Based on the time it takes the projectile to travel those two inches between the sensors, a velocity for the projectile can be determined. Since bullets and other projectiles basically travel at a constant velocity, it is easy for the microcontroller to calculate the delay in microseconds until the picture is taken.
Here’s a link to the Eagle files I used to create the PCBs.
Using the Projectile Sensor with the Camera Axe
There are 3 PCBs and everything is labeled so it’s supper easy to plug them together. You will need the 3.0.04 or newer version of the Camera Axe software. Turn on the Camera Axe and hit menu until you get to the projectile menu. Set the distance you want the bullet to be from the second gate when the picture is taken and then push the right button until you get to the “Trigger on” menu for the projectile sensor and set this to low. Now hit the set button. If the sensor continuously displays the speed of the projectile that means the sensor boards aren’t lined up correctly. Look at it from the side and bend the boards so the emitter is pointed directly at the detectors. Once it’s sitting there waiting for a projectile put your finger through the two sensors and it will report back to you the speed of your finger. Once you get this it’s working.
Mounting the Projectile Sensor
I mounted a projectile sensor to my pellet gun and it is working great. The pellet’s velocity ranges from 985 feet/second to 1060 feet/second. Below are a bunch of pictures of how I did this mounting.
Up until now I’ve been using a photogate sensor and the Camera Axe to take pictures of water and milk droplets. After some research I found many – people – online were using solenoid valves to create droplets and take pictures of them. The big advantage to this method is it’s easy to collide drops which is was very difficult and random using my old method. I decided I’d make a new valve sensor (pre-built version available here) for the Camera Axe and document how to make your own since I didn’t find any detailed instructions or part lists on the web.
I knew I wanted to have a way to trigger my camera on a fairly long exposure in a dark room (I use a 1 second exposure). Then make a water droplet. Wait a little while. Make a second water droplet that would collide with the first droplet’s splash. And then wait a little more until the collision before triggering the flash. With this in mind I started making the different pieces I needed and connecting them together.
The only new circuit I needed was a simple motor driver circuit to drive the solenoid. Below is the one I designed and here are the PCB files I designed in Eagle.
I also made a new version of the Camera Axe software with the valve sensor. You can download this new version (3.0.03) from CameraAxe.com.
Using it with the Camera Axe
Plug your camera into Camera/Flash1. Plug your flash (or flashes using a splitter cable) into Camera/Flash2. Plug this new valve sensor into Sensor1. Below is a picture of my setup. It has two flashes, a camera, the Camera Axe, and the valve sensor.
Go to the valve sensor menu. Set drop1 size to a good starting size like 80. Set drop2 delay and drop2 size to 0 (we will start with only a single drop). Set Flash delay to around 200 ms. Then turn off the lights and press the “Set” button. This will trigger the camera and the flash. Now adjust the flash delay by 10 ms increments until you have a good droplet picture. Below is a video sequence of 20 images stepping through a milk drop splash. The images go from 220 to 420 ms.
If you want to do colliding drops timing is more complicated. As a starting point I’d suggest a drop1 size of 80, drop2 delay of 40, drop2 size 50, and a flash delay of 200 ms. Then adjust the flash delay until you find the time of collision. Then you can start adjusting other timing parameters to get all sorts of different types of pictures.
You can find lots of photos (including droplet pictures) on the Camera Axe flickr group. Below are a few of my favorites from yesterday.
The Electric Eel Wheel is a clever electric spinning wheel making it great for easily spinning the fiber of your choice into yarn! You can use a traditional wheel; however, there are many advantages of this electric wheel design. First of all, the Electric Eel Wheel is lighter and smaller than most spinning wheels making it easier to take your spinning with you.
This electric spinning wheel’s design is based on a Scotch tension design, so it is easy to vary the spin and weight of your yarn. You can easily adjust it to make fine lace yarn as well as softly spun bulky. Another nice feature of the speed control dial is that it can spin the bobbin forward or reverse. Most people in our testing lab appreciated the range of speed that this wheel offers.