Archive for the Hardware Category

Propped up!

Posted in 3D Printing, Hardware, Robotics on May 31, 2020 by asteriondaedalus

So I bought me 6 of these 50mm EDF some time ago. Should have waited, of course, since I really needed 2×3 each of CW and CCW units for my blimp project (based on a pool toy LOL).

The problem then how do I sort out the need for contra rotation to try to balance torque forces?

3D printing fans was the solution!

The bottom left fan is the original. The two on the right tests. The original code for the fans was provided by someone else. Note I did have to modify the code a little, since the source code had some design features that were not needed and also I had to add a disc with hole for the hub attached to the motor. You can see one test with a blade broken off? That was interesting, there appears to be a print phenomenon when the hug wall is too thin and the print does not weld the blades to the hub. Increase the hub thickness and the problem corrects itself.

To get CW and CWW I could run the OpenSCAD software twice BUT you can also mirror the STL file in the Flashforge software.

The problem might be that to be truly reversible, the thread on the hub for the nut should be in the opposite twist, since you always want your rotations tightening the nut. The fit of the printed hub is, however, quite snug and a dab of epoxy would aid and abet the retaining of the nut I suspect.

I was going to start with drive motors in the same config as for the SAAB Double Eagle. These appear aligned so there centre lines meet aft somewheres. For cruising rather than for fine manoeuvring per se. They make a lot of sense, since the lever arm with respect to the CoG is increased from where it would be, if the motors were lined up on the main axes. This then amplifies the turning force of the thrusters, so they can steer with greater effect. Or so I surmise. I haven’t found a paper explaining the configuration … yet.

So, I will use 10mm OD carbon fibre tube to build a frame to attach to Nemo (ROFLMAO) and here is the stl.

Balancing Act

Posted in 3D Printing, AI, Hardware, Robotics on May 4, 2019 by asteriondaedalus

So, I have printed the carcass of a 3d printed balancing robot.

I bought two gimbal motors.

I have my pesky gimbal controller from my lidar experiments.

Go figure, you can buy rock crawler tires for my old Venom Creeper for $5 a pair, so I opted for an indoor/outdoor self balancing robot. To fit the crawler tires I grabbed a 3D model of a beaded 2.2″ rim. I then modified it with freeCAD to fit over the gimbal motor – including a collar to fit around the outboard spindle.

I will mate the gimbal controller with a Sipeed Dock M1W to give the balancing robot autonomous smarts. Especially with the wifi link, it can still lean on more smarts off-board.

Opensprinklette Single!

Posted in Embedded, ESP8266, Hardware, OpenSprinklette on October 15, 2018 by asteriondaedalus

20181015_172706

So, found some info on the board.

Where I thought there was dual throw relay, it’s even better since the second set of terminals are a optocoupler. So, that would be grand for either of a rain gauge input, the audio trigger for dog barking, the flow rate sensor et cetera.

It is otherwise an WeMOS ESP-8266.

What is crazy is that the board thinks of everything and has bidirectional zeners on power and optical inputs so its really for light-industrial applications. That is, includes Transient Voltage Suppressors.

AND! One of the terminals is a regulated 5V output! Just exactly enough for the sound level detection for the dog barking.

Loving it!

I am in so much trouble …

Posted in Chapel, Everything old is new again, Hardware on September 20, 2018 by asteriondaedalus

I was poised to look into a few more ODROID or NANOPI as an extension of my cluster, then a 2U Dell PowerEdge 2950 with dual 3GHz CPU with 8Gb memory is at action, with only two hours to go, no bids so I went with $15.

So that would be 2×4 Core for 8 all up.

Good enough for a Chapel box.

Not sure how I will hide it from the wife.

So, hopefully someone will decide to outbid me.

POST SCRIPT

In the last half hour of the auction, two others made a run.  One an auto bid and one manual.   I worked out that the auto bid had fizzled, they had set their max to $50 just as I had.

So, I sat poised to make a last bid as the auction was about to close – assuming that the manual bidder might be assuming both auto bids had fizzled and weren’t being tracked or that the manual bid would be fumbled in the last few seconds of the web based auction.

Tension was high.

My bid was in the browser waiting for that last button click.

The clock ticking down.

With 10 seconds to go, enough time to get the bid in but to befuddle someone trying to get a counter bid in before close, I … I … I … chickened out.

Fair the well  2U Dell PowerEdge 2950 with dual 3GHz CPU with 8Gb memory, fair the well.  I hope you went to a nice home.

 

 

Zippity do dah, zippity ZAPPP!

Posted in Hardware, Sensing, The after market on December 25, 2016 by asteriondaedalus

Looking at OpenSprinkler circuit, the use of SCR to control the solenoids appears to require the addition of TVS diodes a plenty.

That would be a design decision.

As OpenSprinklette is using relays to drive the 24VAC solenoids we need not apply protection there.

Nuisance factor though is that trying to source non-SMD bidirectional channeled TVS, for the rain gauge input, not so much fun.

For the prototype at least, without any SMD pads on the prototype shield, we are happier with DO-15 or similar package types for the protoboard’s pad spacings.

Luckily though AliExpress came to the rescue.   I have ordered a packet 100 x 36V 1500W bidirectional TVS for US$11.   Now the original design calls for 48V but the markings on the devices suggested unidirectional and the text supporting them did not mention bidirectional.  So, just in case I have ordered 10 x 39V 1500W for US2.80.  That’s the problem with AliExpress and working with penny market vendors therein.  You take what you can get.

So rain gauge and TVS on the way.  I finally decided the shield I am designing will have an input for a rain gauge for those you want a minimal four sector.  The idea of a rain gauge with an ESP8266 has not gone away though.  Where we are using the mqtt and node-red we can build up as we please – over time.

 

There goes that theory

Posted in Doodling, Hardware on December 21, 2015 by asteriondaedalus

As a kid we had an ultrasonic control for the television and I used to torment the dogs with it as they would react whenever it was used.

Fast forward and I am trying to find ways to keep out dogs out of patches of garden and especially the lawn.

So, why not I thought so I got a couple to three ultrasonic sensors for a mere couple of dollars each and threw one onto my trusty old (and expendable) MEGA 1280.

And…

Well either my boxerXstaffy is deaf or I suspect the power output of the tranducer isn’t high enough.

Begs the question then about some of the units you can by from China for a few dollars.

In any event, back to the drawing board.  I will likely need a more expensive and higher powered transducer.

Extra Sensory Perception?

Posted in Embedded, Hardware, Networking, Wifi on May 12, 2015 by asteriondaedalus

What ever it is, the ESP 8226 has read my mind.  Including being able to run LUA and so include MQTT and also things like Actors, CSP, FSM.

esp

 

Especially with NodeMCU on board.

NodeMCU

 

Now with ESP 8226+NodeMCU+MQTT, don’t forget Node-Red.

For my MQTT broker I am using, of course, emqttd as it is erlang based.

For connecting from python on PC, Raspberry Pirate, Beaglebone Black, one needs paho-mqtt.  MQTT has topic much like ROS does … hmm … more reason not to need ROS broker.

In any event … get it … event … never mind, on Android one can use MyMQTT to hook into broker to push and subscribe as a test tool.

oh my god!

Posted in cheap obsolete tech, Development, Embedded, General niff naff and trivia, Hardware, Linux, The downside of Opensource on September 24, 2014 by asteriondaedalus

My ODROID-W turned up. The thing is the size that could almost fit in a matchbox. I am sold! You are right Broadcom, this little board is a threat. Good job Hardkernel.

I know, bad bad bad

Posted in Hardware, Python RULES! on August 20, 2014 by asteriondaedalus

Got a little distracted and now the final push for my Masters – Dissertation.

So, I will have an excuse for patchy hobby bits

In the meantime, my Micropython card came.  So dabbling with that.

Looking at a DCM based IMU although this has enough grunt (I think) for Kalmen filtering.

Missing threads though.

Pity.

How hard is it to program a eeprom?

Posted in cheap obsolete tech, Development, DSP, DSP Laboratory, Hardware on July 29, 2014 by asteriondaedalus

Pretty tricky if it is obsolete so no programmers around for it.

The AT17C65 is the eeprom configurator used in the eval board that the ADMCF328 sits on.

You can probably see where I picked up the fidgety RS232 approach with the AD chip and the optocouplers.

Now I know what you are thinking.  Swap it out for another chip.

Kooky idea.

Except the of the three chips that the ADMCF328 are design to work with (XC17165E, AT17C65, or 37LV65) the AT17C65 is the only one I can readily find on the aftermarket in China.  Absolutely no programmers for it though (although ATMEL have a tease page for a programmer but you can’t get it anymore, and why would you as the chip isn’t stocked anymore).

Thank you Mouser for one idea of how to build a programmer.

Although clincher came from ATMEL site along with the software for the configurator.  So, since the software seems to install on my Windoze box, I just need a DB25 parallel port – yes I said a DB25 parallel port.

Now, this goes either of two ways.  First is a USB to DB25 cable and driver, hopefully the configuration software recognises that arrangement.  Total cost $1.98.

Failing that, $6 to $11 dollars for a PCI card with DB25 parallel port and the ATMEL configurator software.

Failing that, ATMEL has also provided AVR code for programming AT17C65 so I would just code something up on my Arduino MEGA1250.

Okay, so either of 3 ways, 4 if you count no can do – which we don’t do we!

Why all this trouble?

Later chips work slightly differently and there is no guarantee the ADMCF328 will read other chip types.  Since getting a flashing LED on this little DSP chip will be proof I can program it having the right eeprom makes sense to avoid compounding the problem.

Although, the first flashing LED experiment will be against serial port boot.

Stay tuned.

PS, no Maker get out clause no way no how … I like it.