Automatic Target Project

[Cones]

Another small update.

I've now ordered the Hi-Tec HS-325HB Servos to drive the rotation of each target.

Specifications as below. I think with a 6V power supply they should be fast enough to be well within the 0.3 seconds to turn requirements of the ISSF rules. Although this target is for 10m and not 25m.

Control System: +Pulse Width Control 1500usec Neutral
Required Pulse: 3-5 Volt Peak to Peak Square Wave
Operating Voltage: 4.8-6.0 Volts
Operating Temperature Range: -20 to +60 Degree C
Operating Speed (4.8V): 0.19sec/60° at no load
Operating Speed (6.0V): 0.15sec/60° at no load
Stall Torque (4.8V): 42 oz/in (3.0 kg/cm)
Stall Torque (6.0V): 51 oz/in (3.7 kg/cm)
Current Drain (4.8V): 7.4mA/idle and 160mA no load operating
Current Drain (6.0V): 7.7mA/idle and 180mA no load operating
Dead Band Width: 5usec
Operating Angle: 40 Deg. one side pulse traveling 400usec
Direction: Clockwise/Pulse Traveling 1500 to 1900usec
Motor Type: Cored Metal Brush
Potentiometer Drive: 4 Slider/Direct Drive
Bearing Type: Top Ball Bearing
Gear Type: Heavy Duty Karbonite
360 Modifiable: Yes
Connector Wire Length: 11.81" (300mm)
Dimensions: See Schematics
Weight: 1.52oz (43g)


The target holder was tricky. But in the end I decided that I may as well just use a proven design. So I have ordered 5 of the Rika holders that are used on their World Champion target changers.

http://www.schiesssport-buinger.de/Z...ben--1170.html

It should be reasonably easy to just bolt these onto the servo arms with some 2 or 3mm nuts and bolts.

Thanks

Mark

[1066]

Around 30 years ago, when I was doing a lot of UIT pistol shooting I made a turning target setup, giving the right exposure times for all the UIT courses.

I used a ZX 81 computer with 1k memory and interfaced the mechanics via photo transistors fixed to the TV monitor screen. i.e I made a bright spot with a thick black outline flash on the screen at the right time and the photo sensor was stuck on the screen at the right place with a black rubber sucker. The whole thing worked a treat.

I thing one of those golf putting machines that return the ball would be a good basis for a low tech target system. They only cost about £10 and have motor, gearbox, micro switches and battery holder.

[Cones]

I really love the inventiveness of the ZX81 powered target.

I suppose we have it easy now with easy to use micro-controllers with on board I/O and servo control commands.

A lot can be done with a lower tech and lower cost solution. But I hope the extra features I can over with turning each target independently will be well worth the extra effort and cost.

Thanks

Mark

[Cones]

A further update.

The Rika target holders have now arrived and they are perfect for fitting to the servo arms. They have a perfectly flat area underneath, I was worried it may be rounded off or at an angle.

I have used 3mm screws with a few washers as spacers to fix the arms to the base of the Rika holder. The servo arms are a tight push fit onto the plastic spindles of the servo. The idea is they will lift off with a hard impact or for transport.

The next stage is to build the Transmitter board, buttons, battery pack and LCD into the Maplins sloping box I have bought.

I'll do some pictures later tonight.

Thanks

Mark

[Cones]

A big update today.

All the electronic bits are now together.

http://s699.photobucket.com/albums/v...get%20Project/

Lots of pictures in the above link.

This is the Rika target holder which has been modified to fit on top of the servo.

http://i699.photobucket.com/albums/v...Project034.jpg

http://i699.photobucket.com/albums/v...Project032.jpg

http://i699.photobucket.com/albums/v...Project039.jpg

http://i699.photobucket.com/albums/v...Project045.jpg

I drilled the Transmitter box today and installed the pushbuttons and screen. Then I had to make up a small PCB with the pull down resistors for the pushbutton inputs. This is to stop the Arduino board from detecting a floating voltage input which would cause all sorts of false input readings.

http://i699.photobucket.com/albums/v...Project057.jpg

I messed up the LCD slot cut-out a little. Always measure twice and cut once. I think I will look for and aftermarket bezel to hide the small gap.

http://i699.photobucket.com/albums/v...Project048.jpg

The rear of the main panel.
http://i699.photobucket.com/albums/v...Project066.jpg

Connected.
http://i699.photobucket.com/albums/v...Project072.jpg

Finished Transmitter and Receiver Boxes.
http://i699.photobucket.com/albums/v...Project100.jpg

Complete System.
http://i699.photobucket.com/albums/v...Project088.jpg

At the club tomorrow, one of my fellow committee members will hopefully cut the 60mm aluminium box section that will hold the servos.

Thanks

Mark

[Cones]

A couple of videos of it in operation.

Rapid Fire 4 seconds

http://www.youtube.com/watch?v=pbQS0S5GEjo


Random Turning individual target (Try doing this with a normal rapid fire target )

http://www.youtube.com/watch?v=IZ9WqYvUT1c


Comments and further contributions are as ever always welcome.


The software can now be developed further. I added two extra pushbuttons to the box so things like times and number of turns could be altered.

I'd like it to have as many programs as possible to cover all turning target events. Plus a few more fun events that we can use to introduce people to rapid action shooting.

Thanks

Mark

[Cones]

A further update.

The system is now mostly together. Chris has cut the 55mm aluminium box section to hold the servos at 300mm spacing. It even has turn out legs for support.

During operation we did find the first problem.

If the servos all turn together, with a single 6v DC supply the current demands of the servos pulls down the voltage enough to reset the Arduino Mega controller board. This stops the sequence from completing.

No problem it is an easy fix.

I now have two rechargeable battery packs on the system. The 9.6v AA 2100mAh pack powers the Arduino. The 6v AA 2100mAh pack powers the servos.

It all now works perfectly, with very fast turning of the targets.

This weekend I will add the second 9.6v AA pack to the Transmitter box along with a charging socket. Then I should have a fully portable and rechargeable turning target system.

Thanks

Mark