control a NEMA stepper motor with Home Assistant using a D1 mini via ESPHome.
- This project provides a solution for controlling a NEMA stepper motor with Home Assistant (via ESPHome), utilizing a D1 mini board.
- This project consists of a KiCad project that gives you the Gerber files to order a PCB (e.g. at JLCPCB onto which (mostly) passive components (pinheaders/sockets) are soldered. Then you plug on some standard modules you can get from AliExpress, create a device in Home Assistant and are pretty much done.
- For the impatient: Go to Installation.
This is my second "public GitHub" project (see here my first one). I made something (crude) that I nevertheless think might be useful for somebody else. That is also the reason why this readme will be very long - for myself I want to document the story behind it for my records, and (hopefully) for your pleasure :-)
Despite the verbosity of the README, it assumes that you know how to solder, how to work with a multi meter and your way around Home Assistant and ESPHome. Some things here are weirdly specific, while some are infuriatingly generic (assuming a lot of knowhow).
- I did this because I wanted an easy way to drive a stepper via Home Assistant. I couldn't find an idiot-proof end2end solution on the whole internet - everything was just pieces. There was just no "easy" way with all the parts connected (be it SW or HW). So I made this.
- I did this to scratch an itch of mine, and to hone my skills in all the tools along the toolchain. For me, this was really interdisciplinary.
- Drive exactly one NEMA stepper.
- Have only one input voltage that works for the stepper but also powers the rest of the board.
- Have mainly only passive components on the PCB to make it easy to solder.
- Use as many widely available off-the-shelf components and modules as possible over working directly with parts/MCUs.
- Have a compact PCB design.
- Don't use jumpers for MS1/2/3 but solder-bridges (uses less space).
- There are already 3 voltages on the board - make them available.
- Enable usage of unused D1 mini pins via pinheaders.
- Have enough GND pins.
- Have short high-voltage tracks.
- Have everything socketed.
- Have the antenna of the D1 board protrude over the PCB to avoid interference from PCB copper fill (I didn't want to create a keep-out zone; not for a specific reason - I just wanted to make due w/o one).
- The silkscreen on the board shall be self-speaking for modules over the usual 'short nomenclature' (e.g. "J1").
- C1 for stabilizing voltage when the NEMA stepper turns on should be optional.
- No SMD components (to make it easier to solder for novices).
- Voltage pins are intentionally not on one continuous pin row but 3x2.
- Low cost.
- No need for perfectly aligned mounting holes.
- No need for silent steppers (thus use A4988).
- Micro-USB port of the D1 does not need to be available when socketed.
- No need for energy efficiency.
- No need for "perfect" PCB/circuit design (done is better than perfect).
- 1 x PCB (see Installation)
- 1 x D1 Mini (with normal pinheaders looking 'down'; from Ali)
- 1 x A4988 stepper driver (from Ali)
- 1 x MP1584 DC-DC step-down Module with LM2596 (from Ali)
- 1 x KF301- 2Pin 5.0mm screw-terminal (from Ali)
- 4 x 1x8pin female pinheaders 2.54 mm (from Ali)
- 4 x 1x2pin female pinheaders 2.54 mm (from Ali)
- standard 1 row 2.54mm male pinheaders
- (optional) 1 x capacitor (>= 12V, THT radial D5.0mm / P2.00mm)
This will be long. Brace.
- Go to JLCPCB and upload the gerber.zip. Sidenote: I'm neither sponsored nor do I endorse them specifically, I just find them convenient. Make sure you select the correct PCB thickness (1.2 mm). I also set "Remove Order Number" to "Specify a location" (layout contains a field for this). No other special settings.
- Solder the components. No special advice here - it should be pretty straight forward.
- Close the MS1/2/3 solder bridges for microstepping.
- If you populate the C1 capacitor, make sure you leave enough 'height' of the legs to fold it down 90 degrees to lie flat (otherwise the A4988 won't fit above).
- BEFORE putting on all modules and connect power, tune the MP1584 to 5V output. Do this now.
- The A4988 needs to be tuned to output the correct voltage for your NEMA stepper. I will not document here how to do this - please google it.
- Put all modules on the board. Take care of the orientation - there is absolutely no safeguard against voltage reversal or such things.
- Usually an A4988 stepper comes with a mini-heatsink. Put it on.
- Provide 12V input (VCC is left on the screw terminal, GND is right).
- If your NEMA stepper cable is connected like this, then the pins go on the board like shown in the table below (however: don't trust this - your stepper might be different, your cable might be different, etc.):
| row # | color | board pin |
|---|---|---|
| 1 | BLK | 2B |
| 2 | BLU | 2A |
| 3 | GRN | 1B |
| 4 | RED | 1A |
- It is assumed you have a working instance of Home Assistant with a working ESPHome plugin. If not, please google how to get there.
- Create an ESPHome device in Home Assistant with the configuration as basis noted in this file. Modify to your gusto.
- Create an automation in Home Assistant with the configuration noted in this file. Modify to your gusto. Note: The automation includes a slider control that is not documented here. For POC, just run the automation manually.
- If you run the automation (manually), your stepper should turn.
- Read up on the parameters and play around with them - I am intentionally not providing more info or limits or the like.
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This is not the work of a professional, and thus has not been load/fuzzy/destructive-tested. All things could happen, thus this project comes without any warranty. Never use it anywhere in a production situation.
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You can't solder the MP1584 directly on the board even if you don't care about the mouting-hole: The holes for the pins are too small (only the female pin-headers fit, but no the male pinheaders directly). This might be changed on a v2 of the board.
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Todo for v2: Mark the GND pin for the A4988 with silkscreen on the PCB to make it easier to plug in.
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Todo for v2: Mark the diameter of the mounting holes with silkscreen on the PCB. Saves reaching for the caliper.
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Before publishing I got feedback from some dear friends to put ferrit-pearls in series to the 5V for the A4988 and the D1 to make sure the voltage is "clean". I consciously omitted that feedback for simplicity reasons.
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The mounting holes are connected to GND because ... no reason.
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There is intentionally no ESPHome binary provided for download and flashing here.
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I'm neither affiliated with nor do I get money from JLC nor Ali, I just find both convenient.
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Why is there no YT video describing this whole thing? - B/c IMHO YT sucks for technical documentation.
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The KiCad project does not have all components/footprints - I got them from various online sources and didn't track the copyright - sorry.
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I would love to have some useful web GUI in the ESPHome code - but I don't know how to do that.
- May be (re)used for personal/private use only and not sold/licensed for commercial or financial gain. This non-standard license should make it impossible and really difficult for commercial enterprises to profit from my work (pay people to design this!), but enable the hobbyist/enthusiast to work with it.
- If I have inadverently (re-)used your work without either properly attributing it or something, please let me know - I'd be happy to correct this.
Yes please.
Also yes please! (I hope I figure out how this whole pull-request thing works...)