We designed EMIT for projects related to environmental monitoring and control—for use as a smart greenhouse controller, a central heating thermostat, or an environmental data logger, among other applications—but it’s well suited to a wide range of tasks thanks to its feature set, its expandability, and its wall-mountable industrial design. In particular, EMIT is an ideal platform for teaching or learning about the hardware, software, and design aspects of IoT product development.
EMIT was built around the popular 30-pin DOIT ESP32 DEVKIT V1, which is a low-cost, low-power, dual-core, wireless IoT board with integrated Wi-Fi and Bluetooth connectivity. The ESP32 module itself is extremely well supported, of course, and you will find a number of websites and blogs that offer tutorials on both Python and Arduino development.
The 30-pin version of the DEVKIT V1 is affordable and easy to find, both on Amazon and elsewhere. Its schematic has been published online and there are a number of websites with additional information about the board.
In addition to the ESP32, a microSD card socket, and a DC input connector, EMIT includes several key components related to environmental monitoring and control: an AM2302 temperature and humidity sensor, a 5 A relay with a status LED, two user-programmable LEDs, and a 12-pin expansion connector with which you might add a soil moisture probe, an ambient light sensor, an additional relay, a camera, or some other peripheral that is not integrated into the board itself.
Like many products, EMIT started life as a simple breadboard project—a quick way to log the temperature and humidity of our basement so we could determine just how bad that winter really was. But I soon realized two things: first, that we could use it for many other purposes, especially if I added a relay; and second, that I would need to make it a whole lot better looking if I wanted my wife to let me hang it on a wall.
EMIT mounted on the wall
After three more iterations, EMIT is not only stable, reliable, and easy to use, it also fits inside a low-cost, vented, wall-mounted enclosure that will look good just about anywhere.
EMIT can be programmed using either MicroPython or Arduino (C/C++). We will provide step-by-step firmware-development tutorials in both languages so that you can develop EMIT applications in your preferred language.
We’re not interested in just selling a few boards. We created EMIT specifically to help people discover, utilize, and enjoy IoT technology. We designed it to make the hardware element easy, but we have not forgotten about the rest: the firmware, the MQTT broker, and the applications. Accordingly, we intend to publish a full range of tutorials, make our free MQTT broker available for use, and provide working sample code both for EMIT and for various client applications. Finally, we will launch a dedicated forum for EMIT users and do everything we can to help build a rich, self-supporting community around it.
|Range||-40° to +80° C|
|Accuracy (Typical)||+/- 0.5° C (+10° C to +55° C)|
|+/- 1.5° C (< 10° C or > 55° C)|
|Max Error||+/- 2.0° C (at < 10° C or > 55° C)|
|Repeatability (Typical)||+/- 0.2° C|
|Read Frequency||2 seconds max|
|Range||0 to 99.9 %RH|
|Accuracy (Typical)||+/- 2 %RH (20% to 80%)|
|+/- 3 %RH (< 20% or > 80%)|
|Max Error||+/- 5 %RH (at < 20% or > 80%)|
|Repeatability (Typical)||+/- 1 %RH|
|Read Frequency||2 seconds max|
|Voltage Range||7 to 12 VDC|
|Power Consumption||50 mA typical|
|EMIT||Arduino MKR Wi-Fi 1010 + AM2302||MXCHIP AZ3166 IoT DevKit|
|Components||EMIT Board + ESP32 Module||An Arduino MKR Wi-Fi 1010, an AM2302 sensor, a relay Module, and a microSD PCB||An MXCHIP AZ3166 IoT DevKit, a relay Module, and a microSD PCB|
|Operating voltage||7 - 12 VDC||7 - 12 VDC||5 V (USB only)|
|Temperature Sensor||40° to +80° C (integrated)||40° to +80° C (separate PCB)||40° to +80° C (separate PCB)|
|Humidity Sensor||0 to 99.9 %RH (integrated)||0 to 99.9 %RH (separate PCB)||20 to 80 %RH (separate PCB)|
|Relay||5 A SPST (integrated)||10 A SPDT (separate PCB)||10 A SPDT (separate PCB)|
|SD Card holder||Integrated||Separate PCB||Separate PCB|
|ADC resolution||16 bits||12 bits||12 bits|
|Dimensions (LxWxH)||81 x 81 x 18 mm||69 x 54 x 15 mm||140 x 100 x 21 mm|
|Price (US shipping)||$29||$65.51||$70.90|
Our goal is to make EMIT the perfect starting place for your next IoT project, regardless of your ambitions or skill level. To that end, we will provide step-by-step firmware development guides for both MicroPython and Arduino, a free MQTT broker, a sample Python MQTT application client, and an online support forum. You can reach us through the Ask a technical question form on our campaign page.
The EMIT GitHub repository will contain all examples, guides, and hardware files as we add to it. Board schematics are already published
All PCB fabrication and assembly will be carried out by a professional contract manufacturer (CM) chosen from a short list of four providers based on cost, reliability, and capability. We have partnered with this CM before, including on the production of prototype EMIT boards. Once assembled, all boards will come to ControlBits for inspection, testing, final assembly into kits, and packaging.
All boards and kits will be shipped to backers by Crowd Supply’s parent company and fulfillment partner, Mouser Electronics, approximately two months after the end of the campaign. The cost of delivery to US customers is included in the prices shown on the campaign page. International shipments are subject to an additional surcharge, which is displayed just below the product description.
Please see Crowd Supply’s article on Ordering, Paying, Shipping: All the Details for more information on delivery, VAT payments, etc.
As mentioned above, EMIT is now in its third revision, so the hardware and the sample code are both quite stable. There is always some risk, with a project of this nature, that limited availability of key components will delay manufacturing, but we have tried to minimize that risk by pre-ordering unique parts with long lead times. As a result, we are reasonably confident that we will hit the schedule we have set for ourselves. Regardless, we will keep you informed with regular updates as the campaign unfolds.
Produced by ControlBits in Wales, United Kingdom.
Sold and shipped by Crowd Supply.
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