Hi,
as sangaboards are difficult to get in all countries I created a PCB to replace it. This is smaller and more reliable as the Dupont cabling of the self-made Sangebaord. It doas not have LEDs and resistors like the drivers you get with the motors so it needs less power and does not create light pollution. I aded a jumper to enable illumination control (on/off) by the arduino but I didn’t test that feature for now.
Beside the board you need:
1 Arduino Nano
2 JST PH2 Connector
1 USB-C to JST PH connector
3 JST XH5 Connector (*)
2 Capacitors 100nF (*)
2 IC ULN2003APG (*)
1 3-Pin Jumper (* , can also be replaced by a cable bridge)
*) all component marked with star can be taken out of the driver boards shipt with the stepper motors.
You might use sockets for the IC and Arduino if you like.
The Borad was designed with KiCad. You can create Gerber-Files and sent it to a PCB- Manufacturer. Costs are around 6 USD for 5 boards including shipment. I have good experience with ELECROW in China (Elecrow: PCB Prototype & Open Hardware For Makers) but there are hundreds other available. Here is the list of the German microcontroller.net forum Platinenhersteller – Mikrocontroller.net
Known Bugs of Bearboard 1.0 (Bruno) (no functional impact)
- Typo: “waranty” one r is missing
- The two IC are not aligned on the same grit line – no impact but dos not looks so good
- The footprint for the capacitors is a little bit narrow so you have to bend the contracts a little bit
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That can be a very neat solution. Sangaboard started out that way on version 0.2. Unfortunately that page seems to be undiscoverable because it does not call it a Sangaboard.
I had not thought about desoldering the connectors from the supplied boards, they can be hard to get otherwise.
Where are the design files located?
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I’m using Github
About the Connectors you can find them at aliexpress
search for “JST XH 5 pin”
The Power connector I use for LED and Power supply you get with
“JST PH 2 pin”
To connect the Board to an USB power supply I use a " 3A 2-pin USB socket" from Amazon
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Nice work! This is indeed similar to the original 0.2 version, in practice for most people ordering the board from a manufacturer and soldering all the components was too much work compared to a breadboard and wires solution, so I don’t think many of those were made (but there were fewer OFM users back then).
Note that Sangaboard v0.5 is now available for purchase (with shipping to most countries), e.g. from taulab.eu (excuse the shameless plug)
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This is right but a £40.80 at taulab costs 40 pound which is 50 USD plus shipment. This is compared to my solution extremly expensive.
I
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It should be 28GBP+shipping+tax for the Sangaboard. It’s true that if you only get the PCB, use a nano clone and assemble it yourself and have a second power supply it will definitely be cheaper, it’s more of a convenience option and extra features.
Btw if you want to use the new firmware rewrite it supports building it for the Nano (you might need to adjust the wiring configuration). The main advantage from user point of view is the ability to abort moves (for now through the Sangaboard extension, in the next software version this will be built in).
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This is really nice. I certainly so see the parallels with early Sangaboards, I suppose the key of any availability/cost argument is if someone like me who is too terrified to muddle through the PCB purchasing interface is able to get one (without many questions about silk screens and other scary terms).
@sigmaphi how much does 1 board cost if you know how to put it into JLPCB or the like (parts soldered by them), and would you be prepared to sell a populated one for people who are uncomfortable with the ordering and/or soldering process?
I’l find out and come back after my Holidays.10 “empty” boards without solded parts cost 6 USD (shipment included) at Elecrow (Elecrow: PCB Prototype & Open Hardware For Makers). You can simply upload the gerber.zip from the latest release and stay with the default settings.
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I suppose as it is is all through hole, this makes it much more accessible.
Price-Tag for self soldered board:
| Piece |
Qty |
Price |
| Arduino Nano |
1 |
7,00 USD |
| JST XH5 (3 pieces) |
3 |
1,50 USD |
| JST PH2 (3pieces) |
3 |
1,50 USD |
| 2Socket 16 pins |
2 |
0,20 USD |
| 40 pin header dose |
2 |
1,00 USD |
| PCB inl. shipment |
1 |
6,00 USD |
| 2x ULN 2003 (token form the driver boards shipped with the motors) |
2 |
0,00 USD |
| Total |
|
17,20 USD |
I clicked a litlebit arround to find out what the assembly costs might be. A single board is quite expensive due to the basic costs. One board assemby is 40 USD plus component price but 20 board are only 100 USD.
So for a single maker the self soldering solution is better - takes only 15 mins.
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To make it much cheaper we could replace the arduino with two 74HC595 shift registers and do the logic on the Raspi. This would sum up to 11 USD only but would need a bigger software change.Something like this…
In volume, the full surface mount Sangaboard V0.5 makes much more sense, there is a huge difference between component cost, built cost and selling price because of all of the time and support that selling takes if it is all correctly costed. In bulk the simple installation and the power through Sangaboard to the Pi also make a huge difference in the rest of the build and use.
This board really makes sense for the use case of “solder it yourself”, particularly if you have an Arduino to hand, or a pot full of the cheap clones. Even more sense if you have the time to extract connectors from the boards that come with the motors. That is a part of the userbase that I am very keen to make sure that we do support, and I keep the ‘nest of wires’ version as one of my testing sets.
To reduce cost in this use case, the biggest win is probably to replace the Arduino Nano with a Pi Pico. They are the price of an Arduino clone, but without the problem that sometimes the clones are dud or have programming quirks. Programming the Pico is easier as well. We do not yet have a hex file compiled for a simple Pico version, so this is not a current option, but it is possible in principle and would be very helpful. (The Sangaboard V0.5 uses some pins not available on the Pico, so that furmware would not quite work)
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This (the no-mcu version) would cut the cost quite a bit and there should be enough pins, but the OS running on the pi is not realtime which might cause some issues with the timing of the moves (probably mostly for fast autofocus). It might be possible to avoid this for example by pinning the process controlling the motors to a single core and avoiding that core in other things.
If you made an SMD version the assembly costs would go down a bit and as the numbers go up it scales well because of the setup costs, but as William said selling the boards there are other costs, risks and a non-trivial amount of labour ranging from admin to support, which is why the price on taulab.eu is set to 28 GBP.
Reassigning pins in the firmware is a trivial task, so if you do have a pico based version using the new firmware would be easy too.
You are right! If you are not trained in soldering I would also recomment the Sangaboard.
You have to solder about 90 contacts and all have to be in good quality.
With the Sangaboard you also pay for QA testing,logistic and support. This justifies the doubled price (shipment, tax and toll not included). The BearBoard is labled with “No Warrenty!” and this is true!
SANGABOARD has also a big advantage that you do not need an extra USB power supply and extra USB connection from the board to the RASPI. With all that extra cables the OFM looks not that professional but it works.
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