Rotary tool only able to start after turning on water

Hi all,

We’re installing our first FarmBot and encountering a strange issue with the rotary tool. We’d love your help!

When we try to activate the rotary tool after mounting it, it usually doesn’t start. However, if we briefly turn on the water from the peripherals (even for just a second) and then turn it off, the rotary tool becomes operational. This behavior seems odd, and we’re also concerned that activating the water while the rotary tool is mounted might cause damage to the tools.

We suspect this could be related to connectivity issues (for reference, we’re also having trouble with tool verification not functioning properly), but we’re not sure.

Any advice would be greatly appreciated.

Thank you!

Hi @Oma,

This sounds like a contact issue between the UTM’s gold pogo pins and the contacts on the tools. The brief bit of water coming out when the Rotary Tool is attached is probably re-seating the tool so it makes contact, but I would not recommend doing this. You should only use the water peripheral when the watering nozzle tool is attached, or no tool at all.

Instead, first try cleaning and lubricating the gold pogo pins. Sometimes they can get a little sticky from debris or buildup and they don’t pop down all the way to make contact.

If that does not solve the issue, try adding a small spacer under the electrical contact screws on the tools to make them sit a little higher and have a better likelihood of depressing a pogo pin properly. For the tools other than the Rotary Tool, an easy way to do this is by moving the Jumper Link from the bottom inside to the top. For the Rotary Tool you’ll need to use some M3 washers which are unfortunately not provided with the kit but can be picked up for a few cents at the hardware store.

Thank you for the response!

We’ll try and update.

Unfortunately, these tactics didn’t solve the problem. I didn’t get the M3 washers yet but did move the jumper links to the top of the tools (along with cleaning and lubricating) and the tool verification still reads “no tool”.

@roryaronson Do you have more suggestions?
Thank you :raised_hands:

My guess is you’ve already checked all the connections as well.

Can you try removing the three O-rings on the UTM and check if tool verification works? That will allow the tool to seat more snuggly up into the UTM and make even better contact with the pogo pins. If that doesn’t solve the issue there may be a problem with the Farmduino and we can send you a replacement.

Yes, I verified all the connections listed, except for the 90-degree connection between the Y-axis and Z-axis portions of the UTM cable, which I wasn’t sure how to check.

I tried removing the O-rings now, and though it didn’t solve the problem it did provide a few momentary correct readings of the tool verification, which “disappeared” and returned back to showing 1 within seconds.

I saw on other forum posts that some users switched between the pogo pins and even cannibalized the unused ones to support the crucial ones - is that something that is possible in this newer version? do you recommend trying? I want to make sure I try all options before organizing a replacement that will take a while to arrive with shipping…

Thank you for all your help and suggestions.

Meanwhile, I used a multimeter to check the connectivity of the tools and the UTM to the best of my understanding (I’m not a big electronics person). I checked between pogo pin B to the GND of C at the Farmduino after removing the shunts. Both the UTM and the tools had good continuity.

In addition, I added jumper links of other tools to stack them up on one tool (up to 3 jumper links total). This method also proved unsuccessful. When adding the jumper links the tool tilted (image attached) due to the added weight. I assume more powerful magnets might help. However, even when I held it up manually the verification still showed 1.

To be honest, this whole process has become very frustrating. I have read and tried so many different solutions by now (long before posting here) and nothing has worked. I see this is a very common problem in the forum and I do not understand how it can be solved.

Can you hold the jumper link between the pogo pins while the tool is dismounted and read the pin state? That way we could finally check if the pogo pins are not touching the jumper screws on the tool or if the issue is on the wire/farmduino. But it sounds more like a pogo pin issue than a farmduino issue.

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Thank you :pray:
I tried with this part, still no verification, continuity from the multimeter on this is good.

How about the PCB on the UTM? Did you check on the labeled pins on top of it? I think you should be able to take it out after removing the magnet screws.
Measure directly from the tip of the pogo pin against the header pins on the other side of the pcb. Repeat on different pins to see if they all have the same behavior. If everything is fine, make sure that the cable plug sits proper and tight on the yellow pin header on top of the UTM pcb.
Please excuse that unprofessional paint “picture”, just wanted to make sure to give instructions in an understandable way.

@roryaronson I’m wondering why there is only a 2.54mm pin header on the UTM pcb instead of a connection that’s more resistant from getting a loose connection like a molex or even a screwable plug like it seems to be on the UTM wire?

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That is definitely an area of the product that could use improvement. When we first introduced the UTM PCB with Genesis v1.4, we did look at using other connectors, including ones that screwed together. At the time though we didn’t find anything we liked that also fit the tight space requirements - specifically the area between the UTM bosses that the three M5 screws mount to. While we could have changed the entire form factor of the UTM, that was a tradeoff we made to keep UTM/tool compatibility with prior versions.

Fast forward several years and product versions and I’d say that the whole UTM and Tool form factor is due for a breaking change that improves all of the key areas that matter: mounting/dismounting reliability, tool verification/power/comms, ease and robustness of mechanical assembly, supporting a variety of custom tool use cases while not making tradeoffs with out of the box functionality. You can expect this to come in Genesis v2.0, along with other major overhauls of FarmBot’s electrical architecture! And we’ll also make sure to offer upgrade paths from v1.x to v2.0.

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Ok, this test was very informative, thank you :pray:

First, I noticed pin A on the PCB is missing (in picture), which explains the soil sensor’s problems as well according to the pin map.
Second, there was no continuity of Pin C. Even after switching between pogo pin C to pogo pin F (which did have), the situation remained, which leads me to believe that the problem is with the pin itself as well and not the pogo pin.
Finally, I checked again between pogo pin B to pin C on the farmduino and there was poor continuity with high resistance.

To sum up - it seems the the PCB is the source of my problems.
I have access to another FarmBot, and will try to take another PCB and check if it solves the problems (hopefully). If so, will you be able to send me a replacement?

In the meantime, is there a way to redefine the pins so that instead of pin A/C I can use other pins for the same purpose?

Thank you for all your help.

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Glad you were able to find the reason for bad readings. Looks like the other pins do also show corrosion and are about to lose functionality.

Tagging @roryaronson just to make sure you will be heard :slight_smile:

You are able to change the pin assignments on the Sensors page, but that does not work for Pins A,B and L. You could try to bypass the broken connector on the pcb by placing a wire directly from the pogo-pin to the UTM cable.

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Wow! I switched the UTM altogether and finally saw some results!
Tool verification and the rotary tool are working properly. I still need to figure out the soil sensor readings, as they don’t all make sense - but at least they’re now in the intended range, and that’s a win :grinning:
Now I can get to work on some more interesting sequences.
Thank you for your support @Ascend @roryaronson

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Hi @roryaronson, reaching out again regarding the replacement of the faulty UTM :slight_smile:

@Oma I wasn’t able to find your original FarmBot order and your shipping address based on your email. Can you please email contact@farm.bot with your order number and shipping address and I can get that UTM sent your way this week!

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Thank you! Just sent :slight_smile: