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projects:rc-submarine [2011/03/11 08:19]
Mads Chr. Olesen [Pressure sensor/Depth Gauge]
projects:rc-submarine [2013/04/08 13:47] (current)
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 +====== Remote-Controlled Submarine ======
  
 +Inspired by http://blog.xkcd.com/2010/11/05/submarines/ , http://nventivity.com/ROVIAB.html, http://submarineboat.com/rov.htm , http://www.homebuiltrovs.com/
 +
 +The idea will be to build a skeleton, then add a camera, then add propels and steering.
 +It would also be really cool to add some form of sonar, this can probably extend the range of the underwater "vision"?
 +A depth gauge is almost mandatory, then there should be a switch to make the robot automatically maintain the current depth (using the depth propeller).
 +
 +Additional features, too cool to think about ATM:
 +  * Robot arm for grapping stuff
 +  * Sonar
 +  * Topology-sonar using webcam and line lasers. Could be used as an crude [[http://en.wikipedia.org/wiki/Inertial_measurement_unit|IMU]] for attitude determination/navigation, depth-measuring and for scanning the bottom-topology.
 +  * Metal detector/probing stick for determining what something is
 +  * Compressed air-container, allowing release of small amounts of bubbles to indicate position on the surface
 +  * Speaker, to play 8-bit music to the fishes (http://www.youtube.com/watch?v=8pczd4Z9r7c&feature=related)
 +  * Forward thursters ({{http://submarineboat.com/building_bob.htm|"bilge pumps"}}) for fast forward!
 +  * Harpoon for fish hunting (Technically, the operator will need a fishing license. Food for thought: If we make the robot an autonomous hunter, will the robot need a fishing license?)
 +
 +===== People =====
 +  * Mads Chr. Olesen (mchro)
 +  * [[members:mikaelhm|Mikael Harkjær Møller]]
 +  * Alex Birklykke (Webcam/laser sonar)
 +  * [[members:kdhansen|Karl D. Hansen]]
 +The more the merrier; please sign up if you want to help with the project.
 +
 +===== Parts list =====
 +  * Plastic rør (Ø20-30mm ?) + samlinger
 +  * Undervandskamera, vandtæt til 20-30m (se http://www.lh-camerashop.dk/, [[http://www.lh-camerashop.dk/shop.asp?sid=1&rfld=1&m1=&pageload=serievis&gruppeid=23&serieID=5|Vandtæt til 50m, inkl. lys, 3743,75,-]] )
 +  * Tryk-sikker kasse til elektronik
 +  * 1-200m CAT5 kabel
 +  * 1-200m strømkabel (2 ledere)
 +  * 12v batteri (bilbatteri?)
 +  * Propeller (1 dybdepropel, 2 styrepropeller)
 +  * Microcontroller (Arduino?)
 +  * Vandtæt samling til kabel attach/detach
 +
 +==== Propellers ====
 +http://www.homebuiltrovs.com/howtobilgeconversion.html
 +
 +The most common seem to be using bilges and converting to propellers.
 +
 +http://www.biltema.dk/da/Bad/Pumpe/Lansepumpe/Lansepumpe/
 +
 +Power budget for needed propellers (32 l/min models):
 +^ Part ^ Usage (12V) ^
 +| Up motor | 2,5 A |
 +| Left motor | 2,5 A |
 +| Right motor | 2,5 A |
 +**Total: 7,5 A**
 +
 +Forward booster (62 l/min): 4 A
 +
 +Blueprints for shaft converter :[[http://www.homebuiltrovs.com/howtos/bilgeconversion/bilgeadapter.jpg]]
 +
 +We can buy the propels here:
 +[[http://modelskibet.dk/group.asp?group=28]]
 +
 +==== Motor Control ====
 +It is suggested to use a H-bridge configuration with PWM (Pulse Width Modulation) to enable precise control of the thrusters. The H-bridge (L298) is driven by a PWM signal on its EN pins and the direction is controlled via its IN1 and IN2 pins. An Arduino is used as controller together with the small potentiometer-Joystick we have at the hackspace  
 +
 +**Components**\\
 +3A H-bridge L298
 +www.st.com/stonline/books/pdf/docs/1773.pdf\\
 +
 +Schottky Diodes
 +http://platea.pntic.mec.es/~lmarti2/circuitos/lm2576/1N5822.pdf\\
 +
 +5V regulator e.g. 7805
 +Misc. resistors and capacitors
 +==== Camera ====
 +Making a cheap submersible camera: http://www.homebuiltrovs.com/howtosimplehousing1.html , http://www.homebuiltrovs.com/howtocamerapotting.html
 +
 +Maybe using something like http://www.hardware-store.dk/overvagningskamera/spionkamera/prod_3218.html
 +
 +Deal Extreme http://www.dealextreme.com/p/mini-cmos-surveillance-security-camera-with-30-led-night-vision-dc-12v-42034 or http://www.dealextreme.com/p/waterproof-night-vision-ir-30-led-camera-pal-dc-12v-500ma-15756 or http://www.dealextreme.com/p/professional-cmos-surveillance-security-camera-with-36-led-night-vision-silver-dc-12v-47914
 +==== Pressure sensor/Depth Gauge ====
 +If target depth is 50m sensor needs to be able to go to ~600 kPa (~100 Psi)
 +
 +Maybe SPD-100-G-2, e.g. from ELFA.
 +
 +On [[http://seaperch.mit.edu/sensors.php|Sea Perch]] they use Arduino as controller and the MXP4250 by Freescale, as presure sensor. We should be able to get two free samples from the webpage of [[http://www.freescale.com/webapp/sps/site/taxonomy.jsp?nodeId=01126990368716|Freescale]].
 +It is also available on [[https://www.elfaelektronik.dk/elfa3~dk_da/elfa/init.do?item=73-100-14&toc=0|Elfaelektronik.dk]], where then the price is at 130DKK.
 +
 +UPDATE: We now have a [[http://www.google.dk/url?sa=t&source=web&cd=1&ved=0CBkQFjAA&url=http%3A%2F%2Fcache.freescale.com%2Ffiles%2Fsensors%2Fdoc%2Fdata_sheet%2FMPX4250.pdf&rct=j&q=MPX4250GP&ei=vQhwTfqrD8vtsgamyMnwDg&usg=AFQjCNHMHMuzEt7zY6x9RYcFYcOuIMo_HA&cad=rja|MXP4250GP]], thanks to Flemming!
 +===== Potential problems =====
 +==== Protecting the electronics ====
 +Both from water and from the pressure.
 +One solution is to build a air-tight water-proof box, but then there is the pressure to worry about.
 +Maybe it is easier to coat the PCB's in "lak", as done by some overclockers when they watercool?
 +
 +For creating watertight seal, see: http://www.homebuiltrovs.com/howtosealingwireexits.html
 +==== Interference on the cable ====
 +We will probably run both analog (camerafeed) and digital (steering, comm.) through the same, quite long, cable. Maybe we need to go to CAT6? Or two parallel cables?
 +
 +[[http://www.av-cables.dk/computer_kabler/netvaerkskabel/cat5_netvaerkskabel/cat_5e_graa/cat_5e_stp_netvaerkskabel_50_m_1782_da.html|Cat 5e STP 50m - 150,-]]
 +[[http://www.av-cables.dk/computer_kabler/netvaerkskabel/loes_netvaerkskabel/cat_5e/cat_5e_ftp_udendoers_netvaerkskabel_100_meter_3561_da.html|Cat 5e FTP udendørs Netværkskabel 100 meter - 589,-]]
 +
 +
 +==== Lighting ====
 +It quickly gets dark underwater, some form of preferably quite strong lighting is required.
 +
 +==== Protecting the propellers ====
 +Stuff (cable, nastyness, etc.) in propeller = stuck robot. Maybe a form of "gitter" will do, but it might reduce the effect of the rotors as well.
 +
 +==== Air in the skeleton pipes ====
 +The skeleton pipes should probably be airtight, to not increase the weight of the robot dramatically. This should also give the robot "updrift".
 +
 +==== Preventing rolling ====
 +The robot should be kept upright. The standard solution seems to be to have two "pølser" of light material (pvc pipe, plastic foam).
 +
 +Randall Munroe (xkcd) seems to be {{http://imgs.xkcd.com/blag/sub/sub_on_floor.jpg?linkonly|doing without}}.
 +===== Work Sketches =====
 +{{:projects:rc-submarine:uav-sketch1.png?400&direct|Sketch of skeleton}}
 +{{:projects:rc-submarine:uav-sketch2.png?400&direct|Considerations about frontal center of gravity}}
 +
 +===== Software =====
 +Initial design is to have an Arduino controlling the motors onboard, communicate with it over RS485 with a laptop.
 +
 +==== Control Software ====
 +None yet.
 +
 +==== Laptop Software ====
 +Initial GUI can be found at [[https://code.launchpad.net/~shiyee/leo/trunk|Leo at Launchpad]]. The software is naturally named "Leo".
 +
 +
 +
 +===== Pictures from the building process =====
 +{{gallery>:projects:rc-submarine?dsc*&80x80&crop&lightbox}}
 +===== Videos =====
 +{{http://www.youtube.com/v/S2_PeoWhXwE?.swf?600×800}}
Permalink projects/rc-submarine.txt · Last modified: 2013/04/08 13:47 (external edit)

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