Feature request - Charge material and other consumables

Hi there,

Julien here from Machines room London (to become Batch.space soon…). Maybe another makerspace has found a solution but here is the problem:

We have most of our members buying materials and consumables and manual charging them through the portal is not great for keeping track of things and a huge time consuming.

Would be good to add simple fixed price products to the member portal for them to buy.

Idea: They could scan a QR code (similar to bridge) to get charged?

Many thanks for your help!



Hi Julien,

we wrote an external web site that uses the Fabman API to charge predefined product prices to a member. It’s pretty straight forward to write. But it’s not a shop like software, but tailored to our company’s needs, so our code won’t be useful to you.


Hello Julien,

I don’t know if that’s exactly what you’re looking for. But I’m currently working on an open source extension for Fabman for material sales in Happylab. In principle, it is a cabinet with many scales inside. The products are placed on the scales.

The use case then looks like this for the members:

  • Open the cabinet using a chip card
  • Remove the required items
  • Close the cabinet door

Weighing is done before and after the transaction. The system therefore knows who has withdrawn how many of which articles. Charges are then automatically generated in Fabman for the articles.

I write the software in Python3 on a Raspberry Pi. I successfully tested it on a (somewhat chaotic) experimental setup with two scales - see picture below. In the next few weeks I will order the parts for a cabinet with 30+ scales, which will then be used in Happylab. Then I would like to document everything and I am happy if others also benefit from it.

Best regards,


I’m really looking forward to seeing @roland’s solution in action! But in the meantime, there might be other ways to solve your problem.

Could you elaborate on how you currently handle selling materials and what better solution you had in mind? How would members purchase material? How/where would they receive it? When/where would they scan a QR code?

Best regards,

Wow this is amazing thank you so much Roland for the input! I think this is a little bit too much for our scale. But I’m 100% interested for this system in the future once while have more product to sell/hire and more members.


Hi Raphael!

Thank you for your reply!

A member comes in for the laser cutter
_ They want to buy some plywood sheet or any other products (tape, glue etc…) because they forgot to buy some or need more for the project or can’t be bothered to buy somewhere else
_ They come to me: “Oh Julien I want to buy this and this can you had it to my account?”
_ Keep forgetting and hard to keep track but eventually I add a charge to each individual member.

This is only for materials and consumables available in house for them to buy for their work. Could be the same for filament or any other similar products.

I imagine a box or shelves where the materials are lined up/stored and they scan the QR code of the corresponding product they want to buy - this will automatically create a charge to their account.

Hope this helps!


Hey - @walterw can I have a look? I’ve been doing something similar, but haven’t quiet got the right interface yet. We’ve other requirements (book keeping, project tracking, event management) and we’re investigating them all. It’ll definitely be a tool only applicable to us.

Hi Julien,

what do you mean with “having a look”?

I can show you this screenshot, for a start:

I wrote a few extra pages; on one of them you can assign predefined charges to a member.
In order for this to work I use a database and a php backend, plus some javascript of course.

Do you have any specific questions?


That’s excellent @walterw, that’s what I meant.

This is what I imagined. Is it only locally, or do you have it online?
I’ve a dashboard (with automatically updating events, and a summary of upcoming bookings), a database and FabMan integration. I’m using node-red, mysql and javascript myself, deployed on linode, but not active yet.

I’m not formally trained in any of these, so development is pretty slow.
So I have lots of questions of course, but I know what I need to work on for now!
May I ask what type of lab did you do this for? How many members do you have?


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We have it on a web server that is accessible from the Internet; it is protected with a login (through Fabman) though. We use it for all that Fabman can’t and shouldn’t - managing metadata, linking members to MS Dynamics and Owncloud, logging services for our members and some semi-automatic operations like importing logfiles from machines we can’t manage with Fabman.

“My” Maker Space is part of the public company that manages our local Technology park and has been funded mostly by the European Regional Development Fund. In 2019 we had about 100 active members and, adding services, about 90 business customers.
(And this year we’re beginning with marketing, so we expect some noticeable growth.)

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Hi Julien,

I like the idea of a simple point of sale solution for Fabman. I sat down for a few hours and wrote a “MicroPOS” with a barcode scanner in Python on a PasPi.

The sales process is then very simple and intuitive:

  1. Scan the items you want
  2. Swipe a member card to complete the sale

An invoice line is then automatically created for the member.

All you need is a RasPi 3, a display and a barcode scanner and a card reader module.

The article list with the prices are saved in a CSV file. An unique number is assigned to each article, which can then be printed out as a barcode.

@Machinesroom If you are interested in trying this out, please contact me.


Hi Roland,

That sounds like exactly what we would need! Could they use their phone directly as I’m not using the NFC cards for the members? I only have one Admin card.

Many thanks for your help!

@walterw Thank you! I think it’s a bit too complex for our stage of development and ressources to do it but will definitely keep this idea for the future!!

Hi Julien! Thanks for pointing us to fabman!

We are currently working on having an after the fact honesty system.
We set up a POS on our website.

If people use our material they then voluntarily go to our website and pay for it.

But very interested in @roland solution of a locking system.

Hi @Machinesroom,
Right now, my MicroPOS supports NFC cards but not the QR codes feature for authenticating with the mobile phone. We use cards here, therefore I haven’t implemented the QR code feature yet.