Archive for the Hardware Category

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.


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.



Especially with NodeMCU on board.



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.


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.


Got there

Posted in DSP, DSP Laboratory, Hardware on July 23, 2014 by asteriondaedalus

So, a little birds nesting and a lot of fiddling convinced me from moving away from the AD chip with opto-couplers.  So, I went for a MAX232 after all, with benefits.


Why not?

So the setup for the ADMC32x is now:

More sensible

More sensible

The other side is this module is more useful as I can use it on other experiments.  The other way was too sensitive to bumps and knocks and I need a “quiet” interface because the problem is working out whether I am getting code onto the chip – and not whether my birds nested serial interface is up or not.

10MHz clock is still coming from MAX CPLD.