Project Logs

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• Collective

  Morning.Star • 06/16/2018 at 08:11 • 0 comments

  Pandelphi welcomes a new contributor, @Arsenijs
  

  This is very exciting, because he's bringing with him an awful lot of new capabilities in the form of his #ZeroPhone - a Raspberry Pi smartphone 

  This device will power Cub's brain, instead of a regular Pi Zero. There are several very good reasons for this. Currently I'm using a Pi Zero W wired to an Adafruit PWM driver board to control the servos, and an ATMega 328 to read the sensors. To avoid any conflicts with level-shifting, and keep the wiring simple, it uses the two-wire I2C bus.

  Having worked with Ars since ZP Gamma, I know a fair bit about the insides of that too, and its remarkably similar to what I'll need in the robot. The I2C backbone, power management, keyboard interface and networking are all thoughtfully considered solutions to ZeroPhone's requirements and I realised I was reinventing Arsenij's epic design.

  True, the keyboard itself wont be needed and the 328 will be reprogrammed to handle the sensor net. But other than that its the same.
  
  Cub's camera is a standard webcam, plugs into the USB port on a physical level and integrates into Gaussians which now runs as a ZeroPhone App.
  

  The display can also be co-opted to fit behind an eye and provide visual feedback on the system status as well as full diagnostics.
  
  And of course there is the Modem. This is highly useful, because currently Echo cannot talk directly to phones, and the messaging is limited to other Echos. Find My Phone only works in the US too. Using ITTT I can bridge between the Echo and GPRS to send and receive content with any phone.
  Possibly, I can also use the modem to run Alexa outside a WiFi hotspot too.
  
  Another less-than-clever part of Echo's design is an inability to control its audio hardware. Luckily it has a line-out and boots up to its last volume setting, so I can set and ignore it, and use the ZeroPhone's amplifier to control it.
  
  Finally, there is an extensive set of plug-in boards Ars has designed to allow ZP to do its job. It is a hacker's phone after all, and part of it's feature set is an ability to communicate with just about everything. From microwave Radio to IR and UV, plus networking - and it's a standard protocol and pinout.
  

• Heartbeats

  Morning.Star • 06/04/2018 at 09:01 • 0 comments

  AIMos On A Pi

  I've had to do quite a lot of chopping to fit AIMos' motion tracker into a Pi. It was designed to run on a a dual 3.2GHz Intel laptop motherboard at 640x480 resolution at 15 FPS. Using this camera [an old PS2 cam, the one with the differential mics on top] and my Athlon X2 in greyscale at 160x120, it can comfortably hit 125FPS. Great camera, even has a zoom lens and works in near darkness, but it wont fit in the skull.
  

  Pandelphi will have to put up with 320x240 RGB at 5FPS. It will do 8FPS, but I'd rather leave a bit of overhead for AI processing.
  

  The motion tracker doesnt just sense motion. It has a time-of-flight mechanism that records the vector of any motion, besides where it is, and can use this for a predictive model of whats happening. A thrown object still takes around a second to traverse the screen from side to side, AIMos can get 5 grabs and make a vector, computing not only direction but acceleration too.
  

  It can use this to detect gestures without complete recognition. If the analysis doesnt see a complete hand, but its moving like one it could be someone waving. Biometric sensors determine what the motion is likely to be, by checking if there is a changing capacitive field in that direction too.

  I've added Adafruit's PWM library to the Raspberry Pi, and and drive the servo board over I2C directly. This dispenses with the Arduino, which I am mightily happy about. Its been nothing but trouble and required lots of messing around with toolchains and an unreliable data transport.

  Using I2C and a dedicated controller board made all the hassle go away. It compiles in one step, runs nice and stable for over 24 hours [while VNC fell over on the big machine used to view it numerous times] and shuts down cleanly too.
  

  ---

  Here's Gaussians running on the Pi, watching the TV. Not very interesting I'm afraid, but it shows how the tracker pays attention to areas of interest based on movement.
  

  And there's the first test after connecting the servos to the tracker code.

  For some reason, the tracker seems to like the lightshade, and when it catches it at the top edge of the screen centres it rather than the TV. It needs a bit of tweaking to limit the vertical motion, and slow down the frame reacquisition after movement. What it is doing, is making out the outline of the lightshade against a blank background, and when the head moves so does the light.

  Normally there will be objects in the scene, a blank wall causes trouble. This is because when the head moves the entire scene should change and it doesnt, so anything highlighted in it becomes the focus of attention as it moves about.

  To get rid of this annoying behaviour, I'll have to build in boredom, so it searches out other things to look at after a while. AIMos has always found the TV fascinating.

  ---

  
  

• Goldilocks and the Three Rules

  Morning.Star • 05/29/2018 at 22:33 • 2 comments

  I think the skin now is near enough complete.
  

  Just as well really, Mary Shelley would be proud lol. I'm used to monsters, but even I'm a little bothered by this.
  

  Cybeardyne Systems T101 Battle Chassis.

  "Hey, buddy. You got a dead cat in there?"
  

  Hello Handsome. ;-)

  ---

  Interfacing to the hardware
  

  Interfacing to the Echo Dot, so the Panda's eye replicates the light right round the top proved to be a little interesting. I've solved this with waveguides - optical cable glued to a transparent sleeve that fits the Echo lead to a pixel-ring in the eye made with epoxy poured into a mould. This also houses the ranging laser.
  

  The ability to injure is something I've been thinking about a lot. This is a biometric sensor, made with a flat coil of magnet wire stitched to a strip of fabric. It connects via a large-value resistor to a pair of MCU pins, so it can be charged and discharged. It can also be sensed, to see how long it takes to charge or discharge, and that tells the MCU whether it is close to a capacitive source. Usually foil patches are used for the antenna, as a touch sensor.

  However, touch isnt the only thing a Capsense sensor can detect, it can also detect the presence of a person over distance, actually several feet away. Its used primarily for touch though, standard lamps react to the brush of skin to turn on and off, but not clothing, just by measuring the strength of the field. Lamps however are not capable of making a decision to touch you, and find out if they should switch on and off, and a robot is. At least, it is when wearing a bitwise grid of these antenna under its fur, or lining its airframe in all directions.
  

  For the first time, as I am aware at any rate, a machine understands the difference between alive and dead by testing its hypothesis for itself using dedicated sensors. AIMos is keyed to movement, and understands that something moving is either alive or set in motion by life. AI systems like that have to then figure out the content of the image to decide what the moving object is, and infer from that whether it is alive. Biometric sensing cuts across that process, and the robot can pay attention to only living things.

  This brings the exciting possibility of hard-coding Asimov's Three Rules into the system, again for the very first time. As defined, the Three Laws are rather abstract and are more directives governing entire behaviours. Pandelphi's behaviours are fairly simple, the drone reacts to the possibility of attack from pets while monitoring and recording the scene in front of it, monitors its batteries, avoids obstructions and complies within those parameters with instructions. Cubs behaviours are slightly more complex, but harness the same technologies to do the same job.

  These are all programmed responses that I can hard-code in autonomically, things like not laser-ranging a face by mistake, or allowing a childs fingers near the duct ports on the drone, qualify as within the scope of the Three Laws, as does not crashing while avoiding a pet attack.

  Things could get hairy. ;-)
  

• Space Boots

  Morning.Star • 05/26/2018 at 11:48 • 0 comments

  How are you going to do that without your space helmet, Dave?

  Improvise, of course.

  Keeping the outsides out of the insides proved to be a little tough, and as usual it's perhaps a little over-engineered. On top of being flexible, tough, shielded and waterproof, the robot's shell also needs maintenance access, so after thinking to seal the joints into bags, I looked at a way to zip them.
  

  Standard polythene zippy-bags are hard to find in large sizes, the bigger ones were PVC and not very strong so I only used the zips. These were glued to thick white PVC (like you'd find on a hospital bed) using rubber solution, and metallised with foil tape. It is possible to buy large antistatic bags with zips, and some of the equipment even came supplied in them, they just werent big enough.
  

  The cabling system is designed to sneak in via a seam with no trouble and works really nicely.
  

  Space Boots, with airtight zips. These will keep out water, chemicals, noxious gases, radiation and significant positive pressure and still allow easy access to the innards without tools.
  

  Oven Ready Panda. Light meat or Dark meat? ;-)
  

  The fat-suit needs to have the sensor array stitched to it before it can be closed and filled with polystyrene beads, and the fur covering to go over that is still just pinned, but the skeleton is now 90% complete.

  The skull need plating and an access hatch before I can fit that too.
  

  Here's an irony.
  A cheap knockoff of a rare and expensive iconic Chinese product. ;-)
  

  
  

• Skin and Bones

  Morning.Star • 05/23/2018 at 00:00 • 0 comments

  Body Templates

  Having got the frame all in one piece I turned my attention to the skin. I've templated it out in this awful check pattern cloth I've had for years. Its been around since I was a kid, we had a table-cloth the same when I was a toddler, I remember it clearly. Then when the girls were little school uniforms were a total pain to buy, the schools formed alliances with local businesses to supply things like little summer dresses, trousers for winter and of course overpriced jumpers with the school logo embroidered in. Bea fell and tore her trousers and the elbows out of her jumpers, and Molly just grew out of everything as fast as I bought it.

  I learned to repair first, then got bolder and bought fabric to make a set of dresses and trousers copied from the bought ones. After that I only needed to buy enough fabric for another one or two each time, because as they scaled up, I reused the panels for smaller parts on the new ones and saved a fortune.

  I also cut off the jumper logos and stitched them to cheap plain blue sweatshirts. ;-)

  I would have got away with it too, if it werent for those pesky kids... Cloth comes in multiples of a metre, and eventually it wasnt worth the hassle for the price any more as they outgrew it.
  

  The cloth is folded in half to make it symmetrical and reduce the cutting. All identical parts and mirrored parts should be cut this way to preserve the pattern and bias of the weave where possible. Plus its a lot faster...

  Headhunted by corporate industry.

  Right to Bear Arms (Thank you @Thomas Shaddack lol).

  A crown fit for a head.
  

  After much scratching of mine, I managed to approximate the shape I needed by darting in the top edge. 

  Cub is designed for the entire family...
  

  Robot Overlords need cuddles too.

  Cub is filled with polystyrene beads, so needs an inner membrane to keep them all in place. After scaling all the parts correctly with the template, they are transferred to the target material and cut out.

  Then sewn together with a zigzag stitch to accommodate the stretch fabric. Shown fitted with a template skull, thats now complete. Its basically an odd-shaped bag that lays over the frame like a saddle, stuffed with beads, and provides the flesh under the outer skin.

  Well it will do. Right now it looks more like Eeyore than Pooh XD.

  The skull took several attempts trying to smooth out a PVC version of the cardboard one. That didnt work out so well, and in the end I decided framework would work better.

  It did, but even with foam rubber on it, the fabric looked angular over it. Then I remembered a trick I used before on Decal to make polystyrene laminate. It just stretches over the fame and screws down.
  

  It's also monumentally tough. It has been tested to resist multiple blows with a hammer, water, oil, chemicals, and crushing, as has the frame. PVC doesnt shatter or deform, it just springs back into shape so the only real danger to the contents is punctures by a sharp object which would have to be deliberate.

  Bear Metal
  

  So while I was thinking defensively, I added a layer of EM and radiation shielding to harden it beyond anything it will encounter in the home.

  The shielding extends to the waterproof servo boots and works both ways, removing interference from the servos as well as to them so Cub can cope in all environments inside and out.
  

• *Coming Soon* Walks On Water

  Morning.Star • 05/13/2018 at 12:32 • 1 comment

  After pondering on waterproofing, it struck me that I could very easily make Cub fully amphibious just by changing the stuffing.

  An improvement over wadding is polystyrene bead, which I have loads of. This flows inside a soft case like a gel, and will improve the look of the skin as it pulls more naturally over the skeleton.

  The added benefit of course is that it floats, and with a watertight frame and a little weight in the feet to keep it upright in the water all I have to do is work on a gait that propels it forwards and Cub can swim as well as put up with mud and spills.

  Polystyrene is completely inert and weighs very little compared to wadding too, I'm quite excited at the prospect.

  Skinning A Panda

  First I had to come up with a decent design for the body that would also fit the frame.

  This measured out to be 23" nose-to-tail, 14" across the hips and 11" across the shoulders.

  Pandas have a saddle of black that goes from paw to paw up the legs and over the back, but doesnt join across the chest.

  Rear legs are black up to the hips, and the tail is usually white. I've broken with convention though and made the tail black, otherwise it'll look rabbitty... Ears are black, as is the nose, but the distinctive eye patches can in fact be completely absent. Go figure...

  A rare beta version Panda, unpatched.
  

  The skeletronics are covered with polythene sheet which will also keep the beads out, so basically the shell is a funny-shaped bag.

  Here's the template for the body piece, made of two colours of cloth stitched together. It joins down the belly with a zip, one plain and one furry as an outer case. The plain one has the sensor wiring stitched to it, and contains the beads.

• Fantastic Plastic

  Morning.Star • 05/12/2018 at 13:14 • 0 comments

  Update on Cub's progress.

  The frame is just about complete. Upper forelimbs  are built very much like Cardware, a trough of plastic with bearers to hold the servos in place.
  

  It just moulds round the servos from flat sheet.
  

  Thats all the body servos in place, just needs some adjustments...
  

  And banana sensing equipment...
  

  More hot oven and flattening, bit of blowtorching later...
  

  Mmm, nice, very organic. Pity I cant do this with bamboo and my bear hands. ;-)
  

  I think it's childproof, I can stand on it in my boots and it doesnt even have skin on yet, six inches of wadding will make that impervious to accidental damage.
  

  Polythene tube over the limbs from freezer-bags, gathered and hot-glued to the frame will completely waterproof it, same with the electronics including the Echo Dot. How the differential mics will respond to this remains to be seen, but I can add polystyrene to the bulk of the body and head to give it bouyancy so it floats too.

  A totally waterproof skin is pretty impractical, but I can keep liquid out of the innards, and with a removable and washable fur over siliconed cloth, muddy puddles and being left out in the rain dont scare me any more than fizzy drinks or being pissed on by a baby. It happens...
  

  Made me think though.

• Mission Controller

  Morning.Star • 05/07/2018 at 08:54 • 0 comments

  Having run out of screws to build Cub with, I'm now looking into the Naze32 AI pilot.

  Connecting everything up properly is the first order of the day. Everything is pretty much taken care of by the board, its VBat input takes up to 36 volts and it has a built-in 3.3v regulator for the ST core running CleanFlight. It doesnt have an internal 5v supply, this is a bit remiss compared to everything else the board has built in because things like GPS, the receiver board and cameras etc run on 5v.

  The wiring Scheme
  

  I've included a 24v - 5v 2A USB power converter to feed the subsystems Naze doesnt handle. Pi and camera need 5v, as does the Atmel MCU and the camera levelling servos.

  The Atmel has a 8bit Capsense port wired to antennae in the shell. These provide differential biosensing on six sectors and can detect any living creature from as much as a few feet away with good antennae. This reports to the Pi via I2C.

  Also on the Atmel are the collision sensors. These are pairs of active UV photo transmitter-receivers that detect close-range objects hopefully including glass. I did consider using ultrasound, but six of those boards is unnecessary weight if I can get away with tiny photosensors instead. The four horizontal quadrants have full range discrimination and can measure distance, but of the vertical ones only the presence of something to land on is needed as altitude is capped and tightly controlled by the Naze32.

  Landing will need to be performed on flat surfaces and a dedicated charging pad and is an area of research in its own.

  Talking to the Pilot
  

  Hacking into the Naze turned out to be ridiculously simple. CleanFlight recognises many different protocols that have sprung up for receiver boards, mostly proprietary. Luckily one is fairly well documented, and the Naze32 supports a Serial UART input for it.

  MSP - Multiwii Serial Protocol is a packeted solution hosted on the two-wire data transfer built into nearly all microcontrollers. It has the following format.

  Preamble : $M in ASCII.
  Direction : < or > ASCII characters; the direction the data travels in, respective to the controller.
  Size : Number of data bytes sent or zero if the command is a request for data from the controller.
  Command : One of the Message_ID bytes.
  Data : Data bytes expected by the command.
  CRC : Command, Size and Data are XORed and summed.
  

  The commands I'm particularly interested in are
  

  105 : MSP_RC - Send ROLL / PITCH / YAW / THROTTLE / AUX1 / AUX2 / AUX3 / AUX4
  

  200: MSP_Set_Raw_RC - Override ROLL / PITCH / YAW / THROTTLE / AUX1 / AUX2 / AUX3 / AUX4

  Which take 16 bytes of data, 2 bytes per value as uINTs.

  AUX1 is the Camera Gimbal Y Tilt, to level the camera when moving forwards and backwards.
  AUX2 is the Camera Gimbal Y Rotate, to level the camera when moving sideways.
  AUX3 and AUX4 are currently unused.

  104 : MSP_RAW_IMU - Return ACCX / ACCY / ACC Z / GYRX / GYRY / GYRZ / MAGX / MAGY / MAGZ

  Which returns 18 bytes of data, 2 bytes per value as uINTs.
  

  114 : MSP_ANALOG - Return VBAT / POWER / RSSI / AMPS
  

  Which returns 7 bytes, an INT and three uINTs
  

  Using the override command 200, when the Naze doesnt see any data it returns to hovering. That means I can just override it when needed by the PI's AI, and let it get on with its job of flying and monitoring the batteries.

  Building the Turbines

  I've ordered a pack of 'Triprops' - 20 props in all, half of them are CW and half CCW with three blades. These things are everywhere, seem to be a standard with 5mm hubs, all 140mm dia in a range of colours.
  

  Yes of course I ordered them all in purple...
  

  They are way too big of course, I'll have to cut them down. For this I'll mount them on a motor thats itself mounted on a hinge with a pin so I can mark them all identically....

  Read more »

• Tough as old boots in fact

  Morning.Star • 05/06/2018 at 06:37 • 1 comment

  
  After a bit of head-scratching I decided simple was best, and rather than cut and fold these with a single layer I just joined two of them back-to-back. I accidentally dropped the first one on the kitchen floor while I was making them, and it bounced, so I stomped it and kicked it around some with my boots on. No visible difference in appearance even, that will do nicely.
  

  To get the material flat like that, I heated it in an oven for a few minutes at Gas Mark 5 with the door open for observation. Quite how pre-formed sheet handles remains to be seen, but after a few minutes it had turned to a silicone-like texture, the ends of the tube belled slightly and it shrank by about 5mm over 100mm lengthways. There was no visible change in diameter, and all I did was open the tube and flatten it under a bit of wood to form it into sheet.

  I also too the blowtorch to the spine as I managed to get the curve in that off-centre. I bought this tube in 3m lengths presumably from a giant roll originally, they are all curved as a result. Shorter lengths and bigger sizes dont have this problem.

  True to form, Doc commented that there are always lengths of this lining the streets in skips. As a free working material its hard to beat for sure, thanks for pointing that out my friend. :-D

  The frame has worked out to be 12in long without the head, slightly larger than I'd anticipated mentally, and with the head will be bulkier than a cat but similarly sized.

  Those are the fore-legs. I've run out of screws for now, the rest of the frame is dead tube as the back legs dont have knees, and the neck is a gimbal that screws to the tube at the front.

  The fore-legs will be attached so that the servos are canted in at 45 degrees. This is so that both front paws can touch the face. This is also so that Cub can make a stable triangle to walk on, echoed in the back legs and tail, so that Cub can hopefully sit up without falling backwards.

  Cardware's sensor system was a PITA trying to route cables from foils through complicated structures. Cub has a cloth shell to provide form, with the sensor wire array sewn directly to it, and a furry washable skin that zips around it for styling.

  I'll get to work on this as soon as the frame is complete and I know the exact size of the skeleton.
  

• Pandamonium

  Morning.Star • 05/03/2018 at 07:26 • 0 comments

  Rogue: When they come out... does it hurt?

  Wolverine: Every time.
  

  Yeah there's some sharp edges there alright. XD
  

  I've been experimenting with materials again trying to create a tough skeleton system for Pandelphi Cub, having picked up some Polypipe which is light and strong.
  
  I've used this before on numerous occasions, and made some great hardware with it.
  

  AIME's arm with Gripping Hands.
  
  AIME was mostly constructed of Aluminium, but her arms were polypipe. Besides being strong and light, PVC pipe is also extremely slippery and doesnt take glues very well. I used Hot Glue on this, as it holds the best of all. When I was building it, I noticed that the hot glue made the pipe slightly soft and flexible for a moment, but didnt think much on it.
  
  Cubs frame however isnt linear and has some joints in it that are hard to accomplish on round tube, so I had a bit of a play with some scrap to see how it reacted to heat. I was pleasantly surprised, PVC is a mesh of long molecules all tangled together like Felt, and when it is heated it has an extra phase between liquid and solid, where it behaves almost like a fabric. Above 120 degrees or so the molecules loosen up but remain joined together so the material goes floppy, and above 160 degrees it melts to a liquid, so its quite easy to keep it in a handleable range and work it.
  

  This was filmed using the scrap I experimented on :-D I can now film myself filming myself. Better not go there lol, we'll be here all day.
  

  What I learned from heating and cutting the pipe, I put into practise. The material retains all its former strength no matter how many times you heat and form it, but it is possible to tear the stuff as it doesnt stretch or expand during heating.
  

  An experimental servo mount. I had to do a lot of cutting and measuring to get that to fit, there must be an easier way.

  There is as well. This worked out so much better than I hoped.
  

  The screws that mount the servo also join the plates together so they dont move. Its rock solid and will easily deal with the 13kg torque from these evil servos. Metal-Gear Futaba clones with uprated motors and electronics. They are badged as 'Robot' servos, but I see no difference to the mounting and interface from the ones around half a decade ago. My stepdad used to fly RC, and nothing has changed since... Bad show guys, Especially Turnigy and Futaba, the two biggest names out there.

  Make us a hinge, dont just change the description you bums. >;-P
  

  All the tape does is hold down the flap so it doesnt rattle, the two side cheeks cross and the screws go through both, and into the pipe at the other end. It's ludicrously strong and all in one piece, better than a PLA print and probably stronger than an ABS one as well.
  

  Joints in pipe are a total pain in the butt. Polypipe is slippery and smooth, but get it formed properly and its extremely rigid. I copied a bicycle handlebar for this, figuring metal and plastic would behave similarly and it worked really well.
  

  A little heat on the tube and that will straighten right out. ;-)

  I did have a little trouble interfacing to the servos, until I retried the trick I used with Cardware...
  

  The Dead Yoke...

  A cross of material with the arms folded out has the same geometry as the Hip Unit but it doesnt have to be round and braced to take the strain like cardboard.

  This bolts onto the end of a tube that has been split into flanges, or bolts to another one back-to-back to make all the moving joints.
  

  I love how the material pulls around and smooths under my fingers, its a very organic way of working with it and very satisfying.

  Once this is finished, all that remains is to make a panda skin from fabric with a double pocket in the stomach. One to take all the hardware which doesnt even need mounting, and another with a zip to take the Echo Dot.

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