So based on some inspiration from @"tompoland"#121 and a few minor annoyances with it, I've had a play with my niche today. The goals are as follows: * Add an ioniser to the chute to avoid static in the cup * Have controls on the front of the machine instead of the side * A setting to grind by either weight or time, so I can either stop the grind after x grams or x seconds (default setting to stop after 30 seconds) * Possibly a way to vary the motor speed? (I'm not bothered about this, but it's easy to do so why not) The simplest way to do this will be to replace the PCB with a custom one, holding a teensy 4.1 and an HX711 (weight control module) * The bottom wood bit will need remachined to covertly house a scale. I'm terrible at CNC routing so will ask for help on this. * There will be an on/off button, and 2 buttons to set time/weight, as well as a tiny LCD screen which shows settings or the current weight on the scale, or just to tell the current time. - Initially this will just be next to the machine but I could look at integrating it at some point * The new PCB should fit exactly where the old one did, and be switchable. The only functional/noticable difference should be the lack of the switch on the side * I could also add 'shot count/time on' and wireless functionality etc, but they aren't something I'm particularly interested in currently. * I may add some sort of wireless functionality between the board and scale to avoid messy wiring Any ideas/feedback?

Simple Niche Modifications

capuchin

So based on some inspiration from @tompoland and a few minor annoyances with it, I’ve had a play with my niche today.

The goals are as follows:

Add an ioniser to the chute to avoid static in the cup
Have controls on the front of the machine instead of the side
A setting to grind by either weight or time, so I can either stop the grind after x grams or x seconds (default setting to stop after 30 seconds)
Possibly a way to vary the motor speed? (I’m not bothered about this, but it’s easy to do so why not)

The simplest way to do this will be to replace the PCB with a custom one, holding a teensy 4.1 and an HX711 (weight control module)

The bottom wood bit will need remachined to covertly house a scale. I’m terrible at CNC routing so will ask for help on this.
There will be an on/off button, and 2 buttons to set time/weight, as well as a tiny LCD screen which shows settings or the current weight on the scale, or just to tell the current time. - Initially this will just be next to the machine but I could look at integrating it at some point
The new PCB should fit exactly where the old one did, and be switchable. The only functional/noticable difference should be the lack of the switch on the side
I could also add ‘shot count/time on’ and wireless functionality etc, but they aren’t something I’m particularly interested in currently.
I may add some sort of wireless functionality between the board and scale to avoid messy wiring

Any ideas/feedback?

MediumRoastSteam

If you grind by weight, you must ensure the algorithm caters for clearing out the chamber rather than just stop the motor, otherwise you’ll have retention.

HarveyMushman

Assuming you’re doing the grind by weight/time as a means of auto-stopping the grinder, there may be some inspiration in the Fellow Ode.

It has an auto-stop function which works well, not entirely sure how it detects the absence of beans but could be a nice option.

Loonster

I despise the auto-stop on the fellow ode. Give me a simple on/off.

I don’t see the point of grind by weight on a single dose grinder. That would be better left to a grinder with a hopper or a separate bean counter with a hopper.

I like the placement of the side switch. To each their own.

I greatly like the idea of adding an Ionizer. I will be following just for this.

Dusk

I like an auto stop, if the beans take say 15 seconds to grind then a 20 second stop would be my choice

Cuprajake

Depends

If you use the niche for making a big filter brew or espresso could need anywhere from 15s to 45s

Loonster

With the fellow ode, sometimes the beans do not feed. Then I’m turning the damn thing on multiple times. When it works, it’s nice. When it doesn’t, it’s worse than inconvenient.

capuchin

Yes, the autostop is the priority. The stop by weight thing is just a bit of fun as I’m redoing the controller anyway. I was initially thinking of scavenging the original switch and using it as a toggle, and hard coding 30s/60 to it. So you set the time by toggle on the side, then simply hit the grind button. Perhaps I should just do this project like that, an added ionizer, autostop, and a single button. (Maybe I could make the niche icon pressable)

Autostop is useful for me as I often start the grind and then go off to do something, handle the kettle or hob etc as it works.

capuchin

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)

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.

DavecUK

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.

Rob1

If you want to grind by weight you’ll need to find a way of isolating the scales from the vibrations

capuchin

Modified this a little bit.

Confirmed the niche motor is actually AC. Varying motor speed would be easy to do later, but I don’t see the point as it grinds well.
The planetary gearbox (the thing next to the motor that reduces revs to increase torque) is exceptionally well engineered and logical, and I’m happy to see they didn’t go for metal there as a selling point. I’ve scanned the gearbox so in theory could fix it in future. Not worried about it though.
The ‘weighing’ function now is simpler; it detects if a container is under the grinder, if it’s not, it doesn’t grind. (This is probably useless to most people, but I make a mess sometimes)
New board prototyped - Switch will remain the same and in the same place
Up grinds for 30/45 seconds, middle setting grinds indefinitely, down is off
Ioniser is on when grinder is on. Working well, but needs tidying.

Overall it’s a really well designed grinder. Circuit board is weirdly overengineered but ok. (maybe they outsourced this?)

DavecUK

capuchin

The Niche motor is actually DC (Brushed DC). If you reduce the speed, it has a huge effect on Torque.
They didn’t go for metal as the right polymer is superior for this application.
Circuit board is just very simple and robust, make sure you understand exactly what it’s doing before making your own

capuchin

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.

giampiero

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.

dfk41

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.

Cuprajake

Wow

Cuprajake

FadedFrontiers

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 👍

DavecUK

dfk41 You do know that Dave effectively designed the Niche Zero?

No, I helped with testing and suggested some mods to the Zero…but I do have a good appreciation of how it works, and suggested a component or two to be added to the circuit board.