The IOTCRICKET from ThingsOnEdge.COM

See update at the end – and warning – this is a long story: Of course we’ve all seen this form factor before – ESP8266 on a board with power and antenna, FLASH etc.. The ESP-12 is only one of many and now we have a new one…

The biggy here is that the IOT Cricket, I have it on good authority from Sylwester Bala from, is designed to run on AAA and AA batteries – and has a deep sleep mode consuming as little as 0.5 microAmp. You can probably imagine how long the battery lasts under those conditions.

The module comes with pre-installed software and can be OTA’d from a smartphone or APP.

That’s the claim – and now I have my hands on three of these devices to see what this is all about.

ThingsOnEdge approached me – nothing new there but maybe this is something out of the ordinary or maybe it is just because the company is based in the UK – I don’t know yet but I’m going to have a look. I have no axe to grind other than having these product samples – so I suggest giving this a second glance.

The product is still in the validation stage ( so that’s NEW, then), the company has been around sinced 2018 and they are a “small start-up”.

In a nutshell, they are going to provide two options: 1) Local 2) Cloud

Local: You won’t need Cloud at all to configure Crickets, the configuration will be done entirely locally on the Cricket module from the local network – this demand is mainly driven by hobbyists and DIYers

Cloud: There is a Cloud option to configure Crickets remotely – this demand is mainly driven by companies and IOT solution providers

All sounds good to me. Supposedly we’re looking at 15000 events on 2 AAA batteries… MQTT and REST API support, status LED, RTC, temperature sensor, 3v3 out, ESP8266 running at 160Mhz… digital and analog input.. in fact, here’s a copy of their data sheet – if this pans out, I want MORE. MQTT back to Node-Red will float my boat. MQTT rsponses come back in Node-Red no problem


AND NOW – after a short break, fighting delivery and mobile phone companies – I’ve had a play. I’m running one of these boards on a single battery and simply checking temperature. I’ve made some suggestions for the future – more on that later – taking the weekend off.

December 1, 2020 Update – Cricket Rev 1.0

There’s a new module now (I have samples to test – two work – one got bashed on the way here) and new documentation to go with it – here’s a photo. As you can see the units look slightly different with a new metal case .. remote OR local configuration – as before, runs on as little as a single AAA battery but with a catch – you need a large capacitor to handle the initial power burst of the ESP8266 or it simply will NOT run reliably.

One of my first batch of three samples (which arrived here in Spain in a simple envelope) worked immediately on one AAA battery out of the box – another intermittently – the third (bashed in transit) not at all.

I’ve made recommendations for future shipping so we can ignore the third sample – now in the bin. Both of the others work fine but as I have limited capacitors to hand, I simply series’d up two AAA batteries.

You cannot MQTT to the Cricket – so do any setup via the local http: interface or remotely via the cloud. See below. Clearly this device spends most of it’s time asleep in super low power mode and can’t respond to MQTT. However, at regular (or irregular) intervals YOU define, it CAN and does sent out MQTT to either an external MQTT broker or your own – I have MQTT brokers on my Raspberry PIs (and why not, the software is free). My samples are currently firing back the battery state and temperature to the Pi regularly – Sylwester at ThingsOnEdge wrote to me as follows:

"With regards to reading the temperature with the onboard sensor. I think it should provide you quite an accurate temperature value when you set the frequency no lower than 5 mins. The temp sensor is on a chip and it requires some time to dissipate heat."
"There is no way to send a MQTT message directly to Cricket. It is one way communication from Cricket to client devices only. However you can switch on/off temperature as well as other configuration parameters by using You can set Cricket to fetch the remote configuration with intervals and once you change settings in then Cricket fetches it on an aligned wake up interval and adjusts behaviour accordingly. Please see this section how to do it:"

December 2, 2020 Update – packaging issues

I am very pleased with the speed of response from ThingsOnEdge. Like most new companies UK and European companies they have to be careful with shipping charges. After the first lot of samples arrived here in Spain (cost £3 post in case anyone is wondering) in a simple envelope (no padding) which as I said above, dented two and destroyed one of the units. another couple of these tiny modules arrived today – again in a simple envelope, both slightly dented. I’ve commented that it might be worth considering a very thin cardboard addition to the packaging.

Meanwhile, back to the battery question

After wasting much time trying to monitor battery voltage on my digital meter – I did what any self-respecting engineering-type would do and pulled out my handy Owon TA3104 battery-powered tablet scope. See the Cricket bottom right of the image below and my 2 series AAA batteries on the left (covered in tape for lack of a suitable container).

Owon TAO3104 Tablet scope motoring Cricket input voltage over time
Owon TAO3104 Tablet scope motoring Cricket input voltage over time

It is worth pointing out here that with the Cricket battery monitoring set to max resolution (8 bits) the formula to get actual battery voltage is:

Vbatt = (3.5/pow(2,res)) * val

Of course in this case I simply read the incoming voltage on the scope (set to 500mv/div). Even with my experience of ESP8266 devices I’d not really thought of the power up surge and WiFi surge mainly as I’ve not done much with battery powered ESP8266s before. I usually power ESP12 and similar modules with 5v USB supplies. I have had ESP8266 issues in the past with start-up using thin power leads (something I cracked ages ago but didn’t at first apply that experience to the Cricket).

So, despite the key advantage (indeed point) of Cricket being ultra low power, enabling the use of these devices in situations where a power supply simply isn’t practical, it seems you DO have to apply a little common sense in terms of short battery leads etc as the (extremely short) massive voltage drop you see in the scope shot above followed by lesser drops until the WiFi shuts down. Note also the comments from ThingsOnEdge about capacitors.

December 3, 2020 Update – Clarity of Thought?

This seems to be all coming together. Using the online service (a simple web page who’s frequency of automatic updating is determined by the Cricket itself) I set the refresh time in the Cricket to 5 minutes – that means the Cricket will turn itself on every 5 minutes (hence saving battery power) and send to the service (which we can avoid for privacy) and to my own local RPi-based MQTT broker (or theirs), the battery voltage (or that which is easily converted into voltage) and the temperature of the Cricket (assuming updates so infrequent (5 minutes or more) as to not unduly skew the reading).

See image below: The function block does nothing more than the simple voltage conversion I mentioned earlier. The temperature is straight out of the Cricket. That ID number can be gotten from the Cricket itself.

Cricket sending back MQTT results every 5 minutes in Node-Red.

So, by now anyone still reading might be thinking – and the point of this is? As well as the info you see here, the Cricket can return input values…. and what’s so special about that? Nothing much EXCEPT for the low-power aspect. At first, my batteries (AAA * 2) were getting hammered as I was updating every 10 seconds.

Here’s the content of the function block in the image above:

return msg;

As for temperature, don’t be misled by the fractional temperature values -actual accuracy is maybe one degree C.

When I’m done I plan to reduce the updates (and hence WiFi powerups) to every 15 minutes and possibly reduce the voltage measuring A/D from 8 bits to 6 bits or even 5 bits – I need to test but the promise is that 1 AAA (+ 680uF capacitor) or 2 AAA batteries will keep this running for several months – you can’t get that out of Tasmota, ESP-GO, or Espurna. Assuming your WiFi will reach to the far end of your garden (or whatever) this could be useful. I just hope they do more with the inputs – I2c and some libraries for various sensors might be good.

Cricket running on one battery + 1000u cap – short leads

All good stuff – late evening, after leaving the board running all night while watching TV, I returned to find that on one battery and 1000uF 15v cap (because it was handy), the Cricket had failed after a short time, maybe an hour. The offload voltage of the battery was 1.35v. I left the cap in place and re-fitted the original 2 batteries – who’s voltages were low (2.76v combined) but should have still offered reliable operation. After connecting the batteries I pressed the Cricket button briefly to start it up, 5 flashes in a row – no MQTT reporting – nothing – 15 minutes later – nothing.

I wondered if maybe the electrolytic SMT capacitor I’d fitted was reversed – so I removed it with the battery pair in place. At 23:00 that night, the board was correctly updating every 5 minutes – by 6:30am when I got up the next morning it was down to updating maybe once an hour. I turned up the office heat which had dropped from 23c to 16c overnight – I turned on the air-conditioning which in half an hour took the room back to 22c and the Cricket seemed to be getting back to 5 minute intervals but with the odd missed interval. With several readings in a row correctly 5 minutes apart I noted the two last readings – 7:53am and 08:03am – a 10 minute gap.

December 7, 2020 Update – Definitely Sorted

THEN I realised there’s a FORCED UPDATE setting which I’d completely missed, so the Cricket was only sending updates on significant change of temperature. Now I’m leaving the unit with fixed period reporting – and the incoming MQTT is being logged to Grafana and all is well. The image below shows (not very well) temperature and battery readings since mid-after noon on Dec 4, 2020. The battery has not budged from around 2.75v at all in the last few days.

I may yet go back to a single battery, this time with a tiny 680uF 3v3 tantalum capacitor but for now I’m happy to leave the Cricket running to see what happens with the current two batteries as my RPi and Grafana keep an eye on things (the RPi still works after applying last week’s new OS update 🙂 ).

December 21 – Power Rethink

One of my Crickets has been sending battery and temperature readings every 5 minutes since my last update on Dec 7, using 2 (not new) AAA batteries (as I had no tantalum caps handy) until, I just discovered, 2 days ago that it had all stopped. After some testing this morning I decided to temporarily abandon the tiny battery approach, though I’m assured by the design company that a single AAA battery will work when propped up by a tantalum capacitor.

For now however, given the impossibility of getting parts (including battery holders) from the UK (Covid, Christmas, Brexit – what a combination)… so, given that I have umpteen 3v6 Lithium batteries lying around, I’ve wired the Cricket to one of the Lithiums (no capacitor) as the latter even when partly discharged will have lots of peak current capacity. It is all hooked up, no settings were lost when the batteries failed, so Grafana has now resumed taking readings – based on doorbell experience, I thoroughly expect that the logging will continue for several months – though depending on results I may reduce the reporting frequency down to 15 minutes for the sake of it.

The next thing will be to see what else I can get out of these devices.


28 thoughts on “The IOTCRICKET from ThingsOnEdge.COM

    1. I want more already – I’m pondering use with a CR2032 as combined temperature and window sensor – could make a very slim item depending on battery life. I also suggested they need to be careful about pricing as it would not be hard to make a cheapo ESP12 board do the same thing depending on the regulator. This of course id good for those who don’t want to do much tinkering.

        1. just a guess but possible reason is the current spikes needed for radio xmission. A capacitor might solve that problem but it would likely need to be on the larger size.

    2. The trigBoard has a much wider application scope as it uses an ESP32 and exposes many more pins including I2C, SPI, PWM, extra ADC, 2 DACs. It does cost maybe 50% more, though. I think for simple sensors and single relays the IOTCricket looks a smart option and you have to admire the thinking behind it and the execution.

      When I first looked at the Cricket I did find, almost immediately, I wished it included I2C. Although on the 8266 it would have to be software driven. It really would make a huge difference to it’s capabilities and application.

      1. A single diode in series with the Li battery will give 3.5V at the top charge side(4.2V) but it will also effect the low side too. Sometimes that’s a good thing as Li batteries don’t want to be discharged below 3.0V. If the device will run on 2.3V or above then the diode/Li battery setup should work.

        A nice “feature” of the rPiZ/ZW is that it’ll run directly connected to a Li battery and stops operating at ~3.3v. Far better to have battery voltage monitored and messaged out but if not, shutdown will help protect the battery from damage.

      1. Seon has already prototyped a feather format board based on the ESP32-S2. His target price is the same as the Tinypico and it has even more potential, taking advantage of the S2 best bits and taking the power requirements/capabilities of the Tinypico. I’m sure that if he hadn’t had all the issues with his pick & place (a sage well worth following!) he would have released the new board by now.

        I have to say that we are lucky to have all these options and people pushing the boundaries for us. Ultra Low power, wide battery options with plenty of GPIO’s in an affordable format => Santas list is getting longer and longer.

  1. Pete,

    What’s the part number on the RTC chip? I’m wondering if it’s one of the newer models with a built-in rechargeable battery and MOSFET for switching the ESP on and off. It might also explain why they’re not breaking out the I2C …they’re using the ESP to reload the RTC alarm registers and don’t want other devices on the bus to mess things up.


  2. I’ve got two up and running, talking directly to my own MQTT broker and reporting to my Node-red Home control system. Easy to set up and battery powered.

  3. I have an ESP8266 with a BME820 which reports the temperature every six minutes and has run with two AA batteries for six months. The BME820 is powered down during deep sleep to conserve the battery which is connected without a regulator to the ESP8266. I haven’t looked at the startup voltage drop, but I might consider a capacitor to make it run for longer.
    This is to provide additional control for my Vaillant central heating using Node Red and Blynk and another ESP8266 linked to the Vaillant eBus.

  4. Great device but unfortunately any connected sensor will consume power and deplete the battery. It would be nice if the external 3.3V was only switched on at the time of the reading.

    1. As promised, I asked and got a quick response. The 3v3 is only active when the Cricket is awake… so any device getting it’s power from the 3v3 will be turned off when not being read.

      I2c coming in a later revision.

  5. I’ve ordered one to use as a remote temperature monitor, looks like it will do that job just fine but I don’t tink it will do the ob of monitoring doors opening etc. unless you use a reed switch that is normally open when the door is closed which is the oppposite of the standard door switch. The Trigboard on the other hand looks to be perfect for this task but unfortunately it is far too expensive and costs over a tenner to get delivered from the states!

  6. I found the Cricket concept fascinating, and duly ordered one. It arrived, quite securely and safely here in Western Australia, with minimal delay given the covid pandemic issues. It also had postage included in the price – something I see has now been unfortunately superseded by the imposition of an additional cost. I was very impressed with the speedy TOE response when I hit a couple of problems with getting it to work correctly. I’m running mine from 2 AA batteries, and after three days of 5-minute interval MQTT messages, the battery voltage is exactly the same as when I started. Impressive!

  7. No doubt about it, these are not the most flexible or inexpensive ESP8266 devices, but the low-power has it’s uses and I for one cannot fault the communications I’ve had from this small company.

    I can’t quite match your battery voltage consistency – as you know batteries vary wildly, I’m using Kodak AAA alkaline batteries – from Amazon. Offload 3.29v initially, 3.02 offload after 2.8 days… temperature and voltage reading once every 5 minutes via MQTT. Want to comment in here exactly what you are reading every 5 minutes to make comparison easier? I have the board talking to my Raspberry Pi locally (MQTT Broker on the Pi) – I’ve included a photo of the Grafana graph on the Pi.

  8. So I checked my settings again, and it looks like I configured this on 17 Jan – 8 days ago. It is using two (previously partially used) Ikea AA batteries (I find Ikea is a good place to purchase batteries, especially their rechargeable ones). The voltage on startup was 2.73v – I’m using 6 bits of resolution; the RTC is on; I sample temp every 10 minutes (mostly in high 20s – well, it is summer!!) and after a week of continuous use, the voltage this morning is down to 2.54v. Not too bad! No, not the cheapest of devices, although it was very pleasing to see that postage, even ‘down under’ was included – although that has, unfortunately, now changed. And as you say, very impressive service from TOE.

    1. My only concern here is that 2.54v is the offload voltage – we’ll have to wait and see if much lower than that is able to sustain the WiFi startup current – ideally these things should run for months. I started with fresh batteries this time – on jan 22 late morning. I’m doing every 5 minutes, can’t remember if I’m doing 8 bits or 6 bits… voltage and battery measuring. A couple of power cuts in the middle don’t help though my RPI self-recovers from that… it is now lunchtime on 25th – battery total is 3.05v. Temperature varies from 18c-24c – winter here but this is in my office. I’m checking in every day.

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