Robot drummers with MSA-R and MSA-T

[timlaursen]

Hello, I am really excited to begin this project and thought I'd start a thread because I think we'll have lots of questions. Our goal is to build a gang of small percussive robot drummers that we can transport in suitcases and perform with at rock shows and parties. Some may resemble totem poles with whacking clacking parts. Others may look like stuffed animals concealing solenoids and aluminum skeletons. I have worked in model shops and my bandmate runs a metal shop here in Brooklyn so I am excited to get to the mechanics but first the programming. I have read the ancient manuel (from 1994) for my Roland R-70 human rhythm composer (drum machine) and learned how to assign the eight drum sounds we wish to use to MIDI note #'s 0-7. My MSA-R is brand new and everything is working great. I plugged in a 24v solenoid with a 24v 600 mA power supply (we are power hungry and I take full responsibility if I fry a relay) to output terminal 0 and sent it a steady kick at 2 beats per second (120 bpm). The MIDI signal light was blinking and the solenoid was firing but I could see it was not "on" long enough to land the whacker. We came up with this sysex message to obtain a 40ms "on" for outputs 0-7.

F0 00 01 5D 02 01 03 00 03 01 03 02 03 03 03 04 03 05 03 06 03 07 00 4F F7

does this look right?
The only MIDI terminal we have is our Mboxes (pro-tools) and I can't get the MSA to show up when I open Sysex librarian. I have never worked with Sysex messages but we are very determined to build this and understand it. If you have heard of someone sending Sysex through an Mbox I'm curious if it is possible. After we program the MSA-R I will be looking forward to posting pictures of the fun stuff. ~Tim

[revmutt]

Regarding the sysex.

If you are on a Macintosh I would suggest SysEx Librarian. You simply load up the file you want to dump and it should output through your Mbox.

Some or all of the Mboxs have a MIDI indicator of some kind, so you should see some activity and your board will respond with it's light if it receiving a message.

Tommy

[timlaursen]

Thanks Tommy! I got the LED to blink three times and now my solenoids are firing completely to some pretty fast drum machine beats. I didn't see the "play" button on the top left corner of the SysEx librarian screen. Once I clicked on it the MSA-R immediately responded. I just needed to be told it was possible. I am going to hook all 8 outputs up today and I woke up wondering if I need to put protection diodes in there. I know I read about where they go in a forum last night. When we get to the mechanical connection with the shaft on the rotating solenoid I will certainly share our solution. Thank you again.-Tim

[John]

Originally Posted by timlaursen

Thanks Tommy! I got the LED to blink three times and now my solenoids are firing completely to some pretty fast drum machine beats. I didn't see the "play" button on the top left corner of the SysEx librarian screen. Once I clicked on it the MSA-R immediately responded. I just needed to be told it was possible. I am going to hook all 8 outputs up today and I woke up wondering if I need to put protection diodes in there. I know I read about where they go in a forum last night. When we get to the mechanical connection with the shaft on the rotating solenoid I will certainly share our solution. Thank you again.-Tim

Hi Tim,

If you're concerned about the solenoid wiring, please post a diagram and I'll take a look.

Glad to hear you've got things started. Sounds like another interesting project.

[timlaursen]

I am wiring each solenoid in a circuit with it's own power supply. I got the power supplies from all electronics and Jameco. They are 12-24vdc at 500-700Mah. I have 3 MSA-R's. One needs all new relays. I'd like to try turning it into a MSA-P if it is possible and use that one to switch bigger relays. Time for bed, I am loving this project


http://www.youtube.com/watch?v=qFzc42CHxZo

[John]

Originally Posted by timlaursen

I am wiring each solenoid in a circuit with it's own power supply. I got the power supplies from all electronics and Jameco. They are 12-24vdc at 500-700Mah. I have 3 MSA-R's. One needs all new relays. I'd like to try turning it into a MSA-P if it is possible and use that one to switch bigger relays. Time for bed, I am loving this project


http://www.youtube.com/watch?v=qFzc42CHxZo

I like the video. Looking forward to more.

If you want to avoid welding the MSA-R relay contacts shut because of the solenoid current, you can add NPN transistors (like TIP122) to sink the solenoid current. The MSA can then be used to control the transistors.

In the long run, this may be the only way for reliable operation, because the solenoids may have a high "inrush current" that wears the relay contacts.

There is more discussion here:

http://forum.highlyliquid.com/showthread.php?t=3

The diagram is for the MD24, but something similar can be done using the MSA.

[timlaursen]

I got a few late night hours in today and realized I am going to have to re-read all the forums about solenoids sticking and how to use darlintons in the circuit. I've seen multiple people asking about the larger than safe loads, you are a very patient teacher. Is there a location in the highly liquid site where I can place an order for the replacement relays and then I solder them into the MSA? Should I get the types that go into the MSA-T? At this point I have 3 MSA-R's(one brand new, one all switches are burnt out but midi signal is working fine, one has 2 of the 8 switches welded shut (I'm stubborn)).

http://www.youtube.com/watch?v=9CIguGneVHk

[John]

Hi Tim,

Another idea--

If you're going to use transistors to switch the solenoids, you can actually bypass the reed relays altogether. The relay control signal can be taken from the MSA board and can be used to drive an NPN transistor off-board.

Here's a thread where a user is using the signal to drive an LED for each output circuit. But instead of an LED, you can drive the transistor circuit instead:

http://forum.highlyliquid.com/showthread.php?t=34

Basically, you'd be constructing something similar to the MSA-T. The problem with the actual Rev C MSA-T is that the circuit design limits the current draw from each output (it is spec'd at 250mA max). I plan to address the problem with a revised MSA sometime down the road.

In the meantime, you can avoid the limitation by wiring the transistors off-board. Does that make sense?

If you still would like some replacement relays, send me and email and we'll work out the details.

[timlaursen]

Hi John, I have a few questions regarding using the MSA to switch a transistor circuit. In Diagram #1 I do not see where the new power supply for the solenoid is. Does the single line coming out of the MD24 represent 2 wires? In #2 I can't identify the 470 or the 10k parts. I see where the TIP122 goes and the protection diode. This is my first electronics project, sorry. I have been looking at the hardware manuel for the MSA-R and I see there are 4 pins attaching the Reed relays. If I get a MSA T I assume the transistors go into holes labeled "E C B". So , like you suggested, I could remove the relays and go right out of E C B into the tip122 and replace R0-R7 resistors.? Thank you so much, all the info is swirling around and will make sense soon to me. Does #3 work?

[John]

Hi Tim,

Originally Posted by timlaursen

Hi John, I have a few questions regarding using the MSA to switch a transistor circuit. In Diagram #1 I do not see where the new power supply for the solenoid is. Does the single line coming out of the MD24 represent 2 wires?

No, each line represents a single wire. The original diagram assumes that the solenoid uses the same power supply as the MD24.

I have posted a second diagram that incorporates a separate power supply for the solenoid:

http://forum.highlyliquid.com/showth...=1978#post1978

In #2 I can't identify the 470 or the 10k parts. I see where the TIP122 goes and the protection diode. This is my first electronics project, sorry. I have been looking at the hardware manuel for the MSA-R and I see there are 4 pins attaching the Reed relays. If I get a MSA T I assume the transistors go into holes labeled "E C B". So , like you suggested, I could remove the relays and go right out of E C B into the tip122 and replace R0-R7 resistors.? Thank you so much, all the info is swirling around and will make sense soon to me. Does #3 work?

I'm attaching another diagram below. This shows how to use the MSA-R (without modifying it) to control an NPN (TIP122) drive circuit for the solenoid.

The MSA-R output controls a small current that enters the base of the NPN. The NPN "sinks" the much larger current that flows through the solenoid. So the MSA-R outputs will not "burn out".

This is not an ideal setup, because it includes the mechanical MSA-R output when really, only a logic signal is needed. But since you already have the MSA-R units, this is probably the easiest way to go. Once the MSA-T is revised to sink larger currents, you'd be able to just use an MSA-T connected directly to the solenoids/protection diodes.

You'll need to make sure the TIP122 doesn't heat up too much when the solenoid fires. It might be best to reduce the 10k resistor to a smaller value. We can do the calculation--what is the current draw of your solenoids?

Let me know if this helps.

[timlaursen]

Originally Posted by John

This is not an ideal setup, because it includes the mechanical MSA-R output when really, only a logic signal is needed. But since you already have the MSA-R units, this is probably the easiest way to go. Once the MSA-T is revised to sink larger currents, you'd be able to just use an MSA-T connected directly to the solenoids/protection diodes.

You'll need to make sure the TIP122 doesn't heat up too much when the solenoid fires. It might be best to reduce the 10k resistor to a smaller value. We can do the calculation--what is the current draw of your solenoids?

Yes this diagram helps so much. I have come across many posts in the forums concerning loads which exceed the MSA's capabilities. I have placed an order for the protection diodes and the transistors.

TIP122 TRANS NPN DARL 100V 5A TO-220

1N4004G-T RECTIFIER GPP 400V 1A DO-41

Since one of my MSA-R needs new relays, could I take them out and tap into its "logic signal" to control the NPN? We are definitely getting closer, I need to learn how to use a current tester device

[John]

Originally Posted by timlaursen

Since one of my MSA-R needs new relays, could I take them out and tap into its "logic signal" to control the NPN?

Yes. The logic signal for each output 0-7 goes thru the corresponding R0-R7.

On the MSA-R, these resistors are 0-ohms, so you can wire directly to the resistor if you wanted.

[timlaursen]

Hello John, We successfully built 8 transistor circuits and have been enjoying 6AMP power supply handling all of our 24v solenoids. Now we are about to start trying some 110VAC solenoids which can pull 14 pounds in their 1" of throw. We performed with the awkward thing you see in this picture. This is not what we envisioned our final robot to look like. We are working on every part of the system and this is just the way things have taken shape. Here's a video, in the next few weeks we are going to give it another big puch and hopefully things will get stronger and more portable!

http://www.youtube.com/watch?v=56lT1o3mGWI

-Tim

[John]

Originally Posted by timlaursen

Hello John, We successfully built 8 transistor circuits and have been enjoying 6AMP power supply handling all of our 24v solenoids. Now we are about to start trying some 110VAC solenoids which can pull 14 pounds in their 1" of throw. We performed with the awkward thing you see in this picture. This is not what we envisioned our final robot to look like. We are working on every part of the system and this is just the way things have taken shape. Here's a video, in the next few weeks we are going to give it another big puch and hopefully things will get stronger and more portable!

http://www.youtube.com/watch?v=56lT1o3mGWI

-Tim

Tim, thanks for posting the video. I really like the way it sounds.

How do you plan to control the 110VAC solenoids? (The transistor circuit can't do this directly..)

[timlaursen]

We bought a batch of ac relay switches that are controlled by a 5VDC signal. We have not tried it yet, I am waiting for another visit from our local support friend. What do you think?

[John]

Ok, that sounds good. Just make sure to check the specs of the contacts (the part that controls the AC) to make sure it can handle the current & voltage you're using.

Also, check the current draw of the 5V coil. The current is probably small enough to be controlled by the MSA-T--but you should check to make sure.

Be careful--learn how to ground your project to reduce shock hazards.

[timlaursen]

Hi John, the NPN transistor circuit is controlling the AC relays amazingly well. We have played a couple shows already and people are going nuts about the robots. I needed more force for the mechanisms we want to build so now I bought a bunch of 24vdc pneumatic solenoid valves that switch air cylinder which can push/pull 100+ pounds of force. I am going to post a video of what we have so far. You would be proud of the MSA working away on stage with us!

[timlaursen]

Hi John, I just finished this video last night. I am building two new drummers for art shows this summer in NYC

http://www.youtube.com/watch?v=DLWru4YZnhQ

[John]

Tim, thank you! I will blog this. How shall I credit/link you?

I will also include this video, which I enjoyed as well.

http://www.youtube.com/watch?v=3HWIkQT-COc

[timlaursen]

Hi All, I have been having lots of fun building new robots with my multiple MSA's. The last one I made started with a MSA-T rev-k. The transistors were connected to 24vdc power supply. 4 of them switched pneumatic solenoid valves which were 24VDC and 2 way. I used Sqwerl and set channel 1-4 to "latch".That means when the solenoid has no power it is in position "one". The air is sent out port "A" and port "B" is switched to exhaust. The cylinder I use is a 3/4" bore with a 5" throw. When the air goes in one side it extends. when the air goes in the other it contracts (at 100 psi it has about 75 lbs. of force!). When I send the valve a 24VDC signal it sends the air to port "B" and port "A" becomes the exhaust. These air cylinders are VERY POWERFUL. If you want to use one way valves and cylinders then you can set the MSA to a "pulse" and the pneumatic valve will only send air out when it is receiving the 24vdc pulse, otherwise it is "off". one way means the cylinder has a spring which reloads it after the pulse. The solenoids inside the pneumatic valves are small so you can safely switch them with the TIP122 transistors. You can learn a lot about pneumatics from some youtube searches. Also, check out Frightprops.com, they have good video's.
for the other 4 channels I found a great way to use very powerful AC solenoids with the MSA. I went on ebay and bought 8 "Guardian 18-I 120A" solenoids. These little powerhouses are strong. You can send the DC "pulse" signal from the MSA to a SSRI like the POTTER & BRUMFIELD SOLID STATE RELAY SSRT-240D10. It's easy to wire, you send the DC signal to one side marked 5-32vdc. The other side you make an AC circuit with you load (solenoid) and the SSRI as the switch. CAUTION, the 110 AC is a much more serious current than the 24VDC!!! So as your rapid fire MIDI noted are sent to the MSA it is sending pulses of 24 VDC to the SSRI's which are switching on and off the AC. It is instantaneous, the delay will most likely be in your mechanism. I use a 90ms pulse which I believe is enough for the solenoid to fully close. They heat up and I have blown up a few of them. Sometimes when they fail they get really weak. I don't know why. Othertimes they short out, I don't know why. I am testing lots of hardware and spending my hard earned money late night on ebay. We are doing a video doc soon so pictures will be available. Let me know what ya'll think friends!!!!
I have