A coffee read ☕,
Hi there,
After a long year in the making, the thing that almost broke me is finally about to be frozen.
Please, don’t ask why I did it (obviously for the people in need 😅), or how much time and money it took to develop something like this, including choosing the right partners to manufacture all the custom parts integrated into the design.🤐 Was it worth it? Well, depends on what plans you have, for me... yes.
The purpose of this post is to gather insights and maybe help guide someone walking the same path.
The hardest part? Designing a system that’s scalable in width without requiring a bunch of new components keeping the BOM as tight as possible while maintaining the same mechanical principles across all sizes, basically designing all feeder widths at the same time in the head. The goal was to make every part affordable, easy to replace, user-friendly, long-lasting, and of course, as precise as possible.
P.S.__________
If you're interested, please leave a comment, it’ll help me decide
whether to make this available to others or keep it exclusive to my
machine.
__________
C Sample tests, motors working on 10V instead of 12V, and also using only "Sprocket encoder" for positioning:
Say hello to Mantis,
Mantis SMT Feeder System: A Precise and Reliable Feeder for OpenPnP
The Mantis SMT Feeder is an electronic feeder system designed for the OpenPnP community. It focuses on precise and repeatable positioning, ease of use, and cost-effective maintenance. The Mantis Feeder provides reliable performance with a user-friendly interface.
Key Features and Design
The Mantis system consists of three main components:
The system supports various SMT tape sizes, including 8mm, 12mm, 16mm, 24mm, and potentially wider formats. It is designed with precision and durability in mind to ensure consistent performance.
Mantis Feeder PCBA: Electronic Features
The Mantis Feeder PCBA is built around an STM32 MCU running modified Photon Firmware and includes the following features:
Mantis Feeder Controller: Communication and Control
The Mantis Feeder Controller is also based on an STM32 MCU running Marlin firmware. It includes:
Mantis Feeder Bank: Precision and Stability
The Mantis Feeder Bank is designed and machined fully out of aluminum and stainless steel to ensure precise positioning on every plug-in and exchange of the Mantis Feeder. This is achieved through a precisely machined V-groove on the bottom plate that guides the feeder into the locking mechanism. As the feeder approaches the locking mechanism, an additional precision pin ensures accurate alignment for the main locking pin to engage securely.
The locking mechanism and its latch are spring-loaded, securing the feeder firmly against the reference plane for accurate positioning every time. Pressing the locking mechanism latch releases the feeder, automatically pushing it out for quick removal. The locking mechanism is designed to sit flush with the Mantis Feeder in the same Z-level, ensuring a smooth, unobstructed path for the Pick-and-Place machine head.
Mantis Feeder: Mechanical Design
The Mantis Feeder pats are designed and fully machined from aluminum, brass, stainless steel and hardened steel for high precision and durability. The aluminum machined piece, known as the Mantis Feeder Core (MFC), provides structural rigidity, while the back side of the feeder is SLS-printed for an aesthetically pleasing design. The rear housing securely holds the Mantis Feeder PCBA and Peeler Motor, along with custom Peeler brass gears and a worm gear, both supported by double bearings.
To ensure maximum precision and durability:
The internal groove design accommodates different component heights:
Additionally, the Mantis Feeder Bank pitch is 12.5mm, and the Mantis Feeder for 8mm tape has a width of 12mm, a dimension driven by the Drive motor.
Feeder slot allocations:
8mm Feeder - 1 slot
12mm Feeder - 2 slots
16mm Feeder - 2 slots
24mm Feeder - 3 slots
Summary
The Mantis SMT Feeder System is built for precision, reliability, and ease of maintenance. With robust construction, intelligent electronics, and well-designed mechanical components, it provides an efficient solution for OpenPnP users looking for a high-quality feeder system. The combination of machined aluminum, brass, stainless steel and hardened steel parts, spring-loaded locking mechanisms, and precision-machined gears ensures smooth operation and long-lasting performance.
More information soon!
Please leave a comment if this sparks your joy.
Zdenko,
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Greetings,
I’ll be updating this post continuously until the project is complete.
I chose not to share it earlier, even though I started over a year ago. It’s been a bumpy ride, but as always, it’s the finish line that counts the most.
The overall goal of the project was to make these feeders available as a kit, something people can easily assemble and repair themselves if necessary. The design was carefully developed with both DFA (Design for Assembly) and DFM (Design for Manufacturing) principles in mind.
A key challenge was ensuring that the price of the feeder doesn’t scale drastically with width, which is something we often see in commercial solutions. Most of the parts (about 95%) are custom-made and require MOQs, including some technical negotiations with suppliers. That’s why I don’t want users to go through the hassle of sourcing or manufacturing everything on their own, the idea is to make it simple and accessible for those who actually want to use it.
Part of the plan is also to potentially release the electronics for the feeders, as well as the modified Photon Feeder source code on my GitHub. I know how valuable open hardware and firmware can be in projects like this, so if there’s enough interest, I’d love to make those available when the time comes. This would give people the ability to build their own PCBAs and modify the source code if necessary, making it a truly flexible and customizable solution for anyone interested.
I’m trying to gauge if there’s any real interest in this kind of solution, otherwise, it will unfortunately remain dedicated solely to my own build.
Any feedback or response is more than welcome and truly appreciated!
Sharing some of the latest tests, the machine is still WIP,
- Pick Window (Shaky Hands Edition)
- Dual Nozzle Component Pick Test
- Single Nozzle Component Pick Test
Thank you,
Zdenko,
To view this discussion visit https://groups.google.com/d/msgid/openpnp/41c1d96d-cd8e-4443-9573-5332443eabfdn%40googlegroups.com.
Hey Jon,
I also noticed your initial reply in the email thread, but here it just shows "Message has been deleted."
I've seen this happen before with Google Groups, it’s not entirely clear why, but it might be related to some spam filter or other moderation setting. The moderators might know more about the specifics.
In any case, I’ll copy your reply here since every bit of feedback is appreciated, thank you!

On Apr 24, 2025, at 18:04, Zdenko Stanec <zdenko...@gmail.com> wrote:
To view this discussion visit https://groups.google.com/d/msgid/openpnp/41c1d96d-cd8e-4443-9573-5332443eabfdn%40googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/openpnp/812E8021-2EA6-4DC6-9E59-0850801C59E7%40gmail.com.
Hi Dave and Jon,
Thank you both very much for your valuable feedback, I really appreciate it!
The initial goal of the Mantis Feeder project was to keep the cost per feeder around €100 or less, the price I would personally be willing to pay. I won't stress enough how hard this was to achieve, given that 90–95% of the feeder consists of custom parts, made and machined according to tight specifications and tolerances. I also wanted them to be easy to operate, easy to repair, and durable. At first, my plan was to dedicate this design only to my machine, but as time went on, I saw potential to make it available for others who can benefit from them, hence my little "investigation" here to see the interest. Also, I’m happy to say that the €100 target has been achieved. Depending on how people prefer to purchase, the plan is to make options for fully assembled or partially assembled units, which could also reflect in the final price. This way, users have the opportunity to assemble the feeders themselves, which can be really helpful for understanding the mechanics for future maintenance, like lubricating the brass gears and shafts or replacing parts if needed.The feeder is designed with a focus on ease of assembly, following DFA (Design for Assembly) principles. Thanks to this approach, even a partly assembled unit can be completed quickly and without any special tools or complicated steps.
For the 3D printed parts, I chose SLS (Selective Laser Sintering) technology. The price for SLS printing has decreased significantly in recent years, making it accessible even for smaller projects. Plus, with hobby-grade SLS printers on the horizon, I didn't want to limit the design choices to what can be easily achieved with FDM printers. SLS allows for more complex, durable parts with better tolerances, making the overall product more robust.
Regarding pneumatic systems, I decided to move away from them for exactly the reasons Jon pointed out, they tend to be more expensive upfront, noisier, and require additional infrastructure like manifolds, valves, and compressors. They also struggle with flexibility, especially when dealing with smaller or larger components where multiple advances are needed to move 8, 12mm, or more. Additionally, even for 8mm tape, you often need two separate feeder types, one for 2mm advancement and another for 4mm. Not to mention the issues with components jumping, and the overall size and width of the system.
The Mantis feeder, on the other hand, offers control from 2mm to 24mm or even more in a single move across all feeder widths. It even allows for precise 1mm movement or less when combined with the quadrature encoder on the sprocket drive motor. Another addition is a visual aid/pipeline on each pick or every other pick if necessary.
There will still be an initial investment with Mantis Feeders too, mainly in the Mantis Feeder Bank (MFB), which I might bundle with the Mantis Feeder Controller (MFC). However, the plan is to keep this initial cost reasonable and definitely not anywhere near the cost of pneumatic setups.
The MFB also integrates several important components like hardened
bushings, laser-cut parts, springs, connectors, and special engineering
plastic for durable use, but again to keep the final
price accessible for hobbyists and small businesses.
To recap some details:
Feeder pitch: 12.5mm center-to-center for 8mm tape
Feeder widths:
8mm tape → 1 slot
12mm tape → 2 slots
16mm tape → 2 slots
24mm tape → 3 slots
MFB scaling: Widths might be available in increments of 5 feeders (5, 10, 15, 20, etc.), depending on demand.
The project is basically finished, I'm just wrapping up final details now. The 8mm and 12mm feeders will be ready first in the upcoming weeks, with 16mm and 24mm versions following soon after.
Thanks again for your encouragement and insights.
Best regards,
Zdenko,
Greetings JW,
These will be the first "serial production" pieces. After that, I plan to manufacture around 80 units for my own machine.
I'm still collecting feedback to decide whether I want to move forward with offering them to a wider audience. We'll see how much interest there is once I wrap up this chapter and publish a demonstration video in the coming weeks.
Zdenko,To view this discussion visit https://groups.google.com/d/msgid/openpnp/424c3122-85d4-42c3-94d6-7fed9d27da6fn%40googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/openpnp/2f31a5b8-c7b6-475f-9dbe-dc794526c26en%40googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/openpnp/bfc82cc8-af5c-4bcb-9644-07f52553dfb6n%40googlegroups.com.
Hi,
@Clemens – The position measurement is directly proportional to unit/pixel. The test was performed on a 0201 package, which is quite small, the measuring accuracy is pretty good for this setup, but there is always room for improvement.
@Svetozar – Thank you for the kind words. The first machine has found a new owner. Send me a direct email, and I’ll see what I can do.
Zdenko,
To view this discussion visit https://groups.google.com/d/msgid/openpnp/03af4af0-9f47-430a-85d1-20de6d45fab1n%40googlegroups.com.
Hi,
I wanted to share the final stage of development. It has been quite a ride, but I am now closing all remaining open points. The parts will be sent for anodization in about two weeks, and after that I will have the finished product in my hands.
Some additional features implemented:
Feeder protocol and communication performance :
The feeder runs on the standard PhotonFeeder protocol, but the firmware on the Mantis Feeder has been completely rewritten to support the new mechanical and HW design.
Normally, the PhotonFeeder protocol runs over Marlin, which introduces communication delays. To solve this, I developed the Mantis Bridge, a small PCBA with custom firmware that enables extremely fast communication between OpenPnP and the Mantis Feeder.
How Fast is it?
From the moment OpenPnP sends the Feed command, the Mantis Feeder receives it, processes the movement, feeds, and replies back in ~80 ms for 2 mm pitch.
This translates to roughly 12 components/second.
Every additional 2 mm of pitch adds only ~50 ms, meaning for 4 mm pitch the full cycle is ~130 ms, and so on.

RS485 Firmware Update Support :
The Mantis Feeder supports firmware updates over RS485.
A custom bootloader was developed to allow FW updates via RS485 as well as One-Wire EEPROM programming which are located on Mantis Feeder Bank (MFB).
STM32 RS485 Firmware Manager tool was developed which allows this communication. It detects all feeders, loads new FW, and programs them one by one supporting up to 250 feeders on a single bus.

Injection-molded sprockets :
Since the project progressed so far, the final decision was to manufacture injection-molded sprockets to ensure long-term stability and reliability eliminating any production issues such as in laser cut sprockets, etc...(still WIP, in communication with supplier)
Modular reel carrier design :
The reel carrier is designed to be interchangeable and adaptable for different machine types.
You can also use the feeder without the reel holder if you prefer placing the feeder closer to the PCB to reduce machine travel time, and mount the reels elsewhere on the machine


Additional photos:


Thank you for following this build , I hope you like it.
Have a lovely weekend,
Zdenko,
P.S.
I have more ideas for this ecosystem in the future, but first I need to close this chapter.
If you'd like to help or contribute in any form, your support would be greatly appreciated.
Hi,
I wanted to share the final stage of development. It has been quite a ride, but I am now closing all remaining open points. The parts will be sent for anodization in about two weeks, and after that I will have the finished product in my hands.
Some additional features implemented:
Feeder protocol and communication performance :
The feeder runs on the standard PhotonFeeder protocol, but the firmware on the Mantis Feeder has been completely rewritten to support the new mechanical and HW design.
Normally, the PhotonFeeder protocol runs over Marlin, which introduces communication delays. To solve this, I developed the Mantis Bridge, a small PCBA with custom firmware that enables extremely fast communication between OpenPnP and the Mantis Feeder.
How Fast is it?
From the moment OpenPnP sends the Feed command, the Mantis Feeder receives it, processes the movement, feeds, and replies back in ~80 ms for 2 mm pitch.
This translates to roughly 12 components/second.
Every additional 2 mm of pitch adds only ~50 ms, meaning for 4 mm pitch the full cycle is ~130 ms, and so on.
<log.jpg>
RS485 Firmware Update Support :
The Mantis Feeder supports firmware updates over RS485.
A custom bootloader was developed to allow FW updates via RS485 as well as One-Wire EEPROM programming which are located on Mantis Feeder Bank (MFB).
STM32 RS485 Firmware Manager tool was developed which allows this communication. It detects all feeders, loads new FW, and programs them one by one supporting up to 250 feeders on a single bus.
<Tool.jpg>
Injection-molded sprockets :
Since the project progressed so far, the final decision was to manufacture injection-molded sprockets to ensure long-term stability and reliability eliminating any production issues such as in laser cut sprockets, etc...(still WIP, in communication with supplier)
Modular reel carrier design :
The reel carrier is designed to be interchangeable and adaptable for different machine types.
You can also use the feeder without the reel holder if you prefer placing the feeder closer to the PCB to reduce machine travel time, and mount the reels elsewhere on the machine
<WhatsApp Image 2025-11-01 at 10.17.35_a32d6e59_1440x1080.jpg>
<WhatsApp Image 2025-11-01 at 10.16.58_66f13ce6_1440x1080.jpg>
Additional photos:
<WhatsApp Image 2025-11-01 at 10.22.52_51fb3e63_1440x1080.jpg><Screenshot 2025-11-01 102836.jpg>
To view this discussion visit https://groups.google.com/d/msgid/openpnp/edb23804-3f94-400d-96f5-83fe135dea62n%40googlegroups.com.
<log.jpg>
<WhatsApp Image 2025-11-01 at 10.16.58_66f13ce6_1440x1080.jpg>
<Tool.jpg>
<WhatsApp Image 2025-11-01 at 10.22.52_51fb3e63_1440x1080.jpg>
<Screenshot 2025-11-01 102836.jpg>