The only problem with this method would be that I couldn’t display things like runtime or easily change the time. (It’d also be the end of any chance of variable speed.) On the upside it’d make the mod really cheap to do. (Probably talking a tenner or so total and 10 minutes to install the replacement board and chute, button notwithstanding)
The autostop could probably be done without modifying the niche at all. Leave the niche turned on and control the power externally. The trigger for shutoff could be done in several ways. Sensing the drop in current would likely be the most accurate.
Loonster The autostop could probably be done without modifying the niche at all. Leave the niche turned on and control the power externally. The trigger for shutoff could be done in several ways. Sensing the drop in current would likely be the most accurate.
The only problem is the grinder needs to run for a while after the beans have ground to clear the chamber…so something with a delay is required….and these circuits do exist.
If you want to grind by weight you’ll need to find a way of isolating the scales from the vibrations
Modified this a little bit.
Overall it’s a really well designed grinder. Circuit board is weirdly overengineered but ok. (maybe they outsourced this?)
DavecUK It says 50-60hz on it and 220-240v. Very little indication it’s DC, other than what the website says. DC rectified with that circuit would give us 340v~ in the UK. Gearbox reduces the speed/increases the torque, and will be the primary method of reducing revs. To vary speed you’d generally want to modulate the gearbox rather than voltage. May also be possible that the randomly huge resistor on the board is doing it, but you’d question why that wasn’t done at gearbox level (as above.)
Else they designed the gearbox, and the motor changed so they needed to stick on that huge resistor. If Niche want to send me an old unit to tear down, I’m happy to correct myself but for now the evidence says its an AC motor. (which there’s nothing wrong with.)
I had a google now and this is a guy on reddit who seems to share a lot of my opinions on it: (he even calculates rectified voltage almost as I do, only our opinions on the resistor seem to diverge a lot)
"I am an EE and was fascinated by that electronics board. What is it even doing there? It’s an AC motor and a switch, yet, there are four beefy diodes that I presume form a full bridge rectifier, ad well as a huge power resistor. Is this all for the little light? There do not appear to be any active components on the board, so we can rule out speed control or anything fancy like that.
It just seems strangely over-complex for what it needs to do."
"Either the label on the motor or the claim on the Indiegogo page is wrong then. Just from seeing the electronics in the video, I can see a rectifier and some passives, nothing more. If you rectify AC power where I live, you get ~170VDC, and there are no markings on that motor that suggest that is the voltage it should run at. If I were in the UK, that number would be ~330VDC, also not on the label.
A DC motor will normally have a motor controller, as well as feedback to control the speed, etc, none of which are here. It wouldn’t make sense to put a DC motor in there and then run it “open loop” without control.
Honestly, is that it is an AC motor, but I guess I’d have to disassemble my unit to see, and I’m not gonna."
ps. I wouldn’t say it’s the ‘ideal’ polymer, but it’s fine. Cheap and cheerful to replace too in the event of failures, even if the company is no longer around.
capuchin The fact you can plug in a grinder in a 230V AC socket, does not always means that the motor is AC. Anyway you already got many confirmation that the Niche Zero motor is DC.
capuchin You do know that Dave effectively designed the Niche Zero? Do you not think he knows better than you and the idiot on Reddit matey? Can I ask how many top selling grinders you have designed, just so I can go and take a look at one.
I thought the review linked on Reddit was very positive, he said the build quality was very good and that it doesn’t come much better.
I think his only gripe was the dozing cup which he didn’t like - a very minor issue.
dfk41 You do know that Dave effectively designed the Niche Zero? Do you not think he knows better than you and the idiot on Reddit matey? Can I ask how many top selling grinders you have designed, just so I can go and take a look at one.
No need to attack the guy, correcting him his enough - he clearly didn’t know 👍
It’s a brushed permanent magnet DC motor, designed to run from crudely rectified mains AC - no need for smoothing or speed control which explains why the board is as it is.
Lots of advantages to using this type of motor and very few disadvantages - they are cheap, easily procured in the exact specifications that are required and start up quickly with full torque - minimal ramping. They will be using different motors specified to regional electricity supplies.
Brushless might have been better but I presume Niche in their wisdom have decided that the brushes will last the life of the grinder - and they are not impossible to swap over as a supplied part if and when they fail.
The way people attack others here for perceived slights is astounding. Given that being an AC or DC motor means nothing to you; it’s the same thing, it’s a weird hill to fight on. It’s an electronics discussion relevant to understanding how it works and modification, and makes no difference in everyday use. Yet there are 3-4 replies jumping in excitedly to a conversation not relevant to them, and that they know nothing about and haven’t participated in thus far.
I’ve found the datasheet now, and if Dave wanted to clarify he could easily give the datasheet and the datasheet for the gearbox from chiaphua. I’m sure he didn’t need the sycophantic stuff in any event.
To conclude: It is a dc motor, but weirdly labeled. The HZ value doesn’t belong there at all as DC doesn’t oscillate. The reason for the extra large resistor and huge capacitor is because the bridge would rectify too high, so it needs toned down.
Gagaryn Aye thanks, found the datasheet and got there in the end. I assume the last bit is a cost thing. The standout feature of this one seems to be its relative size although that does come with the need for more gearing caveat. I’ll leave datasheet and supplier here for completeness.
i was merely supplying you the pics i had, to help
the ‘wow’ was the fact you were kinda arguing with the guy that helped to design it, fwiw i dont think its that motor above, im not really sure if i can say more, so i wont,
Decent De1pro v1.45 - Niche Duo - Niche Zero - Decent is the best machine ever made -
capuchin The way people attack others here for perceived slights is astounding.
I did not attack anybody, so stop creating a false narrative. You might not like the fact that I corrected you….get over it. You come onto the forum announcing your views like the resident expert……when you stick your head above the parapet etc
