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If you need a quick estimate how much it costs to build an SMD assembly prototype, you need to roughly estimate the hours it takes to execute every step of assembly. Here we are offering times obtained by averaging our last 10 jobs. Clearly, this is not a precise science, because the PCB complexity varies. Yet, to our surprise, the hours do not differ that much. Mind, that all our jobs fit these categories: 4-layer boards 80% SMD parts boards…

A lot of startups are too busy to create their next hit firmware to bother with organizing a workflow, like an automatic software release version numbering. Petty, because it is so helpful to setup a proper company culture up front and force every programer to modify their development environment to automatically execute a simple script after each compile. This post only illustrates only one way about it. We elected to name our firmware with three number groups separated with a…

In the previous post we have described how we program our embedded designs using a TagConnect cable using the STLINK-V3SET programmer. We have received a request to do the same for the much less expensive STLIN-V3MODS programmer board. STLINK-V3MODS programmer board is a simplified board of its more complete cousin STLINK-V3MINI. Confused? Here is a list: STLINK-V3SET is a full featured programmer in a plastic enclosure (our adapter plugs directly) STLINK-V3MINI is a small PCB board, no enclosure, has STDC14…

Growing plants indoors is about light and water management. This article shares some thought on the LED Grow Light design calculations. There are many suppliers offering horticulture LEDs. We have decided to use one of the leading brands Luxeon SunPlus LEDs. We knew that the LEDs should be kept as cool as possible. Our design uses Aluclad PCB, which conducts heat well. The PCB design is simple placing LEDs in series, but we recommend to follow the LED manufacturer’s guide…

(if you want to know how much time is needed to hand assemble a board, see our other blog) Are you impatient waiting for the assembly house building your prototype? Maybe you should try to build them quicker by hand. We design and build so many new products per year, that we were practically forced to build our own boards. It often happens, that before we go to our company automatic assembly lines, we hand build several engineering iterations of…

Growing plants indoors is about light and water management. This article shares some thought on the later, specifically we show you schematics section how to connect the water pump and the flow sensor to common microprocessor.. TESLA Microgreens Stand is an automatic machine not unlike an Italian espresso machine or professional dishwasher. When looking from outside, all three might look like they have nothing in common. Inside is another matter, they all must precisely measure and distribute water. From embedded…

Previous post described our reasons for developing Dielectric Soil Moisture Sensor. Here we would like to share some thoughts about the probes of these sensors. In general, any two metal bars or PCB traces will work with the same oscillator. What will change with each setup is the probe’s capacitance and sensitivity. The sensitivity can be balanced to desired level with an analog OpAmp amplifier. One thing is for sure: it is worth to build a development platform like we…

As written in the previous post, there was a need to properly tune the 3rd overtone components. While we could simply solder and desolder the two components directly on the first version of the TESLA SS01 Capacitive Soil Sensor, it quickly became tedious. We have decided to obtain two items: an inductance decade box and a capacitance decade box. Browsing for them we have discovered they are mostly offering them with larger values, or they are very expensive. At the…

Our Automatic Microgreens Stand needs a lot of electronic parts, among them a Soil Moisture Sensor. When growing anything; soil, water, light and controlling their quantity becomes very important for good results. There is a lot of information and sensor products available on Internet. Majority of them are inexpensive sensors based on resistive measurement of the soil. These are not cutting it for us – they are not corrosion proof and more importantly, their measurement is soil type dependent. We…

So you are going to develop using chips from ST. Those Italians and French have not only great food, but great chips! One will need a programmer and a debugger. They have this nice new STLINK-V3, looks good, let’s get it. Cool, now we need to connect it to OUR board. From our previous developments using dsPIC from Microchip, we fell in love with their robust version of the spring-loaded Tag-Connect cable: RJ12-6-pin male connector on one end; Tag-Connect 6-pin…