ZeroPlus Logic Cube

tmpE089I recently took a look at the ZeroPlus Arduino Starter Kit – well, this logic analyser is not a starter version! This particular model, the Lap-C 322000 has 32 channels  and a bandwidth of 75Mhz. It has 64Mb memory, 2Mbit per-channel depth and is the top of the line in the LAP-C range.  The unit comes complete with manual, probes and hard case and works on USB 1.1 and USB 2.0 – Read on…

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Arduino for Beginners

ZeroPlusWe rarely cover projects for beginners in the blog and I guess that’s because most of the people I know who are into technology have been there for a while.  But as I found out when I first started getting into Linux a couple of years ago, it is awfully useful if you have a helping hand!

Only this morning we discussed a power supply which required some soldering – and that, when you think about it is not something a beginner is likely to have.  In this blog entry we’ll assume a brain, a computer and a little money to buy this kit – looks like a great Christmas present to me!  Read on…

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ESP8266 and ATMEGA2560 Mega Board

ESP8266 and Atmega 2560You may recall my blog entry about my “universal peripheral” – using the little Arduino Nano or similar clones with an ESP8266 – with the former providing GPIO via an I2c connection.

Well, that led me to getting this little number from Banggood – the Wemos Atmega + WiFi R2 Atmega2560+ESP8266 32Mb Memory board.

It’s not 32 MEG of course – it is 4MB – but that’s the same as a normal ESP12. but with the GPIO power of an Atmega 2560 – all in one neat board.

Initial impressions – it looks well put together.  According to the underside, it takes DC 7-16v in – and has DC out at 5v 1.6A and 3.3v at 1 amp – so it actually is a little more than just the two boards – looks like there’s lots of power there for peripherals.

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AD584 Precision Reference

AD584-M Voltage ReferenceI’ve been waiting for this little item for some time now… and today it turned up – a very neat Perspex box that requires micro-usb – and which gives out on demand (button press) 2,5v, 5.0v, 7.5v and 10v.

Accuracy? It is hand-written on the back. The unit outputs the following: 2.4939v, 5.00248v, 7.49906v and 10.00194v.

Or, to 3 digits accuracy, 2.494 , 5.002, 4.799, 10.001v

That’s pretty accurate I would say. So, I did what I purchased the unit for and tested my various gadgets.

Firstly the EM125 hand-held scope and meter from Banggood… 2.506 (+0.24% error), 5.007 (+0.14% error) , 7.51 (+0.13% error)  and 10.02 (+0.20% error) – I don’t think that’s bad for a cheapo hand-held scope!

Next, my trusty IO-TECH Smart-B meter… the most expensive one I have in the UK (that is about to change dramatically) – 2.48 (-0.8% error), 4.98 (-0.40% error) , 7.47 (-0.40% error), 9.97 (-0.30% error). Granted it was only £15 but that’s 4x the cheapest ones… not impressed.

Finally my Owon SDS1102 (mean voltage) 2.516 (+0.64% error), 5.079 (+1.58% error), 7,588 (+1.17% error), 10.10 (+1.00% error) – could be better – but read on..

Then I realised I had never used the self-calibration function on the SDS1102!!! I ran that and did the tests again… 2.505 (+0.20% error), 5.005 (+0.10% error) , 7.510 (+0.13% error), 10.001 (0)% error)

Not too surprising that the Owon would be the most accurate as it is the most expensive instrument. I was surprised however that the EM125 turned out to be better than my meter.

So for now, the Owon SDS1102 will be my go-to meter (not exactly pocket sized but ok on the bench) but I believe something altogether more special is on it’s way. More on that, soon.

I’ll add the BitScope later, this was not on the bench at the time.

This little test unit was cheap – and granted it is not going to find everyday use – but it certainly has put my mind at ease. The button on the front selects between the 4 voltages and long-press turns it on and off. There’s a Lithium battery inside the “case” for running without power.


Poor Man’s Signal Generator

AD9833I can’t remember how, but when messing around with scopes and awaiting my new signal generator (more of that in the coming weeks), the AD9833 Programmable Waveform Generator came to my attention.  Take a look at this Ebay link. This would you believe is a signal generator. Without those connectors you can purchase the board even more cheaply. So I paid £5, you can get  boards at half of that.

How would you like a dirt cheap signal generator with:

  • 1hz-12Mhz range
  • 4-button operation (6 buttons with 2 memories)
  • Sine, Square or Triangle Outputs
  • Non-volatile settings
  • Audio button feedback

And there’s more. Read on…

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Korad KA3005D Bench Supply

Just a quick one here as it’s all in the video below. This is about the  Korad KA3005D Bench Power Supply – a nice solid unit able to provide up to 30v at up to 5a.   I had visions of some lightweight switched job – but no – a honking great transformer inside.

4 memories, voltage and current limiting AND optional cut-out, fine and course controls for voltage and current and – not expensive.

All in all very nice – but for two things – no English manual (but that IS available online) and it came with two power cables neither of which were British – but apart from that – spot on – see what you think. Anyone got one? If so how is it working for you? I wrote to teh manufacturer about M5, not only did they send me an up to date manual but immediately cleared up the question about the M5 indicator (as did readers of the blog and video).  Select memory M4, turn the dial to the right and you're talking to memory M5.

Yes I’ve had the scope out – 5v 4 amps – the output hardly budged (a few mV) and no appreciable noise output.

Using a meter I trust (for now, until my precision voltage reference turns up),  the output from the power supply off-load was in all cases within 0.22% of my meter reading!!   On the 5v out setting, I applied 2.33 amps load and the output voltage dropped 0.41%

Again at 5v, with a 4.66 amp load, the 5v output dropped 2.01%

Other power supply stuff from Banggood here.


INA219/ESP8266 and Node Red

tmpB2D1In a previous blog entry we were playing with the INA219 voltage and current monitor. Here I team the little board up with the ESP8266 and Node-Red.

In this entry, I have teamed up the INA219 with my ESP8266 code which already has a driver in for this chip and also has support for the SSD1306 – hence, thanks to MQTT, this little combined chip can easily show the current status on the on-board display and also show it on a Node-Red dashboard in gauges and also a combined graph.

Please note that I have updated the ESP8266 code (v2.3.15) and changed how this works as I ended up writing way too fast to the device… this code works.

Power MonitorOf course that’s how I’ve done it – armed with info you can do any variation you like. I’ve set the graph limits here to 6 volts, I guess it would make sense to set it to 30v.

I’m also using a 1 second inject node, perhaps something more flexible and externally programmable would be better – in which case you could have different graphing speeds. Nice for checking battery charging?

As my ESP8266 code (documented on the blog – see right menu, ROMS available, recently updated) already does all the display and INA219 handling, everything was done in Node-Red.


Power Monitor

Here is the code for “Process Chart”

var ina=JSON.parse(msg.payload);
var msg1={};
var msg2={};
var v=Math.round((ina.voltage/1000.0)*100)/100;
var a=Math.round((ina.current/1000.0)*100)/100;
var w=Math.round((v*a)*100)/100;

msg.payload=v; msg.topic="voltage";
msg1.payload=a; msg1.topic="current";
msg2.payload=w; msg2.topic="watts";

The injector node has a topic of ina219/toesp (assuming you set the ID of the board to “ina219” of course) and a payload (string) of:


The 1 on the end implies a 64 pixel high ssd1306 display attached, a 0 would imply a 32 pixel high display and no parameter would assume no display and simply send the information out. Initialisation of the INA219 and optionally the display happens at first use – no need for separate init.

I’ve now added range adjustment – you MUST have the latest node-red-dashboard for this…

return msg;

In the case of setting the maximum range to 6 – the payload for that button (drop down and select JSON) is {"ymax":6} – have as many as you want!!

And that’s it  - simples…

I’ve not shown current here as I need to lower that LOAD resistor on the INA219 but you will normally see voltage, current and power in that graph! Once I figure out how to correctly reprogram the chip I’ll add that into the ESP8266 INA219 code.

I have some 0.025R resistors on the way but from China so it’ll be weeks. Meanwhile of course this is perfectly usable.

The first version of the software proved unreliable and so anyone who first looked at this may have noticed I've updated the ESP software. The current version I have sitting on a window on my PC.

It has now been running at 1 sample per second for the last 96 hours without a glitch. At some point I'll add disk (sqlite most likely) logging - though in Node-Red that is simple enough to do.


Big Timer

tmp17DBBig Timer is probably the best timing node for Node-Red, providing a general purpose timer as well as  handling summer/winter correctly as well as (importantly) lighting up time (for which it needs longitude and latitude). After all you probably don’t turn the outside lights on at 6pm!! You turn them on when it gets DARK.

New: “toggle” mode. Now with new seconds timer mode AND updated for the latest Node-Red 0.17.5+ including new help formatting and tips on input and output.

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The BitScope Mini Oscilloscope

Let’s face it, if you want an oscilloscope and logic analyser that fits in your shirt pocket, your choices are a tad limited.

Regular readers may recall that way back in 2016, I did a short review of the BitScope Micro, a VERY portable circuit board which, coupled with suitable software for the Raspberry Pi or PC, acted as an oscilloscope or logic analyser. Well, this is it’s “big” brother.

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LiPro Balance Charger

LIPRO BALANCE CHARGEREvery time I see a video about charging or testing batteries, I tend to see one of these shiny blue units (or similar) – so I thought it was about time I got one! 

The LiPro Balance Charger (or rather, a clone as we will see later) is pocket sized and has an input socket on the left… it takes from 11v to 18v input… and trust me it objects loudly if you put in a higher voltage as I did – beeps like crazy – but then that’s better than blowing up, any day.

I have lots of Lithium and other types of batteries lying around and some of the claims for them are bordering on the ridiculous – and I’ve always thought, wouldn’t it be nice to actually be able to CHECK the claims – and of course another battery charger never goes to waste. Read on…

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