So to start this thread I did a quick test of the operation of the 7mm throw mini linear servo motor. The thread is intended to show test results as we perform them, and the uses of these mini servo's. What I hope we can accomplish here is define the drive pulse specs, reliability, and share Arduino or other control sketches, as well a showcase projects these were used in for everyone's benefit. Possible uses include activation of crossing gates, semaphores, turnouts, engine house doors, etc. Their small size and reasonable price make them useful for many Z Scale projects. Here is a quick initial test video of the servo, showing it's size and throw: This is what I bought for testing: https://www.amazon.com/dp/B08BXN32WX
Well if you can get a working semaphore that would be impressive. Is the idea tie a rod to servo then up the shaft to the signal?
Dang, I was just venturing into lighting and the use of fiber optics, and you have to go and introduce this…… It should be interesting though to see the various uses.
The thing about my use case, is I need two servos to be mounted inside a train depot, then operate the linkages on the outside. I am thinking maybe I can come up with an up through the roof mechanism, and make the linkage out of .010" EDM wire. Alternately, I might mount the servo's on the far wall in the depot, and just have a linkage feed through hole that is a pivot point, making it a short throw lever with a ring loop on the exterior portion of the linkage wire. From there mount another wire straight up to the semaphore blades. Still thinking, but remember, this is all to fit in my Lester WA depot, and I guess that means I need to build a third version of it to look like the prototype. This time I will have the semaphore animation, and switching on and off room lighting and sounds all built inside the same tiny depot: But you can see how small electronics are these days, so I think I can fit it all in:
Some reference info on these servos: DR2770-JR D1015HC 1.5g Digital Micro Linear Servo 4.8-8.4V Servo Specification: Operating Voltage: 4.8-8.4V 4.8V: 0.1kg.f @ 0.2sec / 9mm 6.0V: 0.14kg.f @ 0.15sec / 9mm 7.4V: 0.17kg.f @ 0.12sec / 9mm 8.4V: 0.2kg.f @ 0.11sec / 9mm Motor Type: Coreless motor(CM) Stroke: 9mm Pulse width: 900~2100us Signal: Digital Gear Type: Plastic Bearing: No Wire length: 100mm Temperature: -20C°~ +60C° Size: 21.2 X 15 X 6mm Net Weight: 1.5g JR connector: Red +, Brown -, Orange S ---------------------------------------Arduino--------------------- This servo works very well. I had to adjust the minimum pulse width to 832µs with the command myServo.setMinimumPulse(832); to allow a full range positioning from 0˚ to 180˚. With the 540µs default setting, the servo would automatically return to “home” (180˚) whenever positioned below 27˚. Reference > Libraries > Servo Servo Device Control Allows Arduino boards to control a variety of servo motors. This library can control a great number of servos. It makes careful use of timers: the library can control 12 servos using only 1 timer. On the Arduino Due you can control up to 60 servos. Go to repository Compatibility This library is compatible with the avr, megaavr, sam, samd, nrf52, stm32f4, mbed, mbed_nano, mbed_portenta, mbed_rp2040 architectures so you should be able to use it on the following Arduino boards: Arduino Micro Arduino Leonardo Arduino Mega Arduino Due Arduino MKR FOX 1200 Arduino MKR GSM 1400 Arduino MKR NB 1500 Arduino MKR VIDOR 4000 Arduino MKR WAN 1300 (LoRa connectivity) Arduino MKR WAN 1310 Arduino MKR WiFi 1010 Arduino MKR ZERO (I2S bus & SD for sound, music & digital audio data) Arduino MKR1000 WIFI Arduino Nano Arduino Nano 33 BLE Arduino Nano 33 IoT Arduino Nano Every Arduino Uno Arduino Uno WiFi REV2 Arduino Yún Arduino Zero Portenta H7 Releases To use this library, open the Library Manager in the Arduino IDE and install it from there. 1.1.8 (latest) 1.1.7 1.1.6 1.1.5 1.1.4 1.1.3 1.1.2 1.1.1 1.1.0 1.0.3 1.0.2 1.0.1 1.0.0 Usage This library allows an Arduino board to control RC (hobby) servo motors. Servos have integrated gears and a shaft that can be precisely controlled. Standard servos allow the shaft to be positioned at various angles, usually between 0 and 180 degrees. Continuous rotation servos allow the rotation of the shaft to be set to various speeds. The Servo library supports up to 12 motors on most Arduino boards and 48 on the Arduino Mega. On boards other than the Mega, use of the library disables analogWrite() (PWM) functionality on pins 9 and 10, whether or not there is a Servo on those pins. On the Mega, up to 12 servos can be used without interfering with PWM functionality; use of 12 to 23 motors will disable PWM on pins 11 and 12. To use this library: #include <Servo.h> Circuit Servo motors have three wires: power, ground, and signal. The power wire is typically red, and should be connected to the 5V pin on the Arduino board. The ground wire is typically black or brown and should be connected to a ground pin on the Arduino board. The signal pin is typically yellow, orange or white and should be connected to a digital pin on the Arduino board. Note that servos draw considerable power, so if you need to drive more than one or two, you’ll probably need to power them from a separate supply (i.e. not the 5V pin on your Arduino). Be sure to connect the grounds of the Arduino and external power supply together. Examples Knob: control the shaft of a servo motor by turning a potentiometer Sweep: sweeps the shaft of a servo motor back and forth Methods attach() write() writeMicroseconds() read() attached() detach()
Cool, hope you can build a turnout with it. My experiments showed that a handlaid turnout can't be reliably operated by this servo when using a direct drive method - the lever is directly attached to the 3d printed part which holds the pcb tie where point rails are attached. Due to backlash and play and wobble in the servo itself, it could not move to the exactly the same position, so I dropped the idea of using this servo. Would be interested to see what other people can do with it. The metal rod could work though, but then you have to somehow hide the drive.
I remember those servos several years ago in bed it into larger scale turnouts. For your design, I would try to do a single throw like your EDM wire in straight tube versus hooking up pivot points and loops. They just never really have the reliability. For service ability could this be mounted outside (on the backside or on non-viewable side)? I would agree with the hand laid track throws. Even if you notch both sides of the rail base (near the frog) to make a pseudo hinge point and thin the inside real base near the points, it probably still doesn’t have the torque. I will be building my modular Layout with Atlas turnouts so easy to draw. The biggest contribution is keeping a low profile compared to the MR five turnouts drives motors. But, I can’t stand the unstable servos that have too high torque load, so they’re constantly trying to get themselves in the position! And the worse the wiring. The various fixed lengths need to be folded back on themselves. Making your own is futile. I bought both a prefessional and commercial crimper but just not worth the hassle to make perfect lengths. Click and there is a bag already made for $10. I designed with Ron crank style that mounts under the points that well.
The problem I noticed with these servos is their lifetime. The feedback for position for these servos is a potentiometer and these small servos has a open sliding pot that even a little dust will start having jitters and quickly die. I would use the standard S3003 size servos and check the manufacturer with the best reliability. There are some smaller higher quality ones but non of the plastic or the cheap ones last long. The other problem is when you replace these servos the position will not be the same for the signal so you got to make sure you have compression and elongation tension in the linkage. Somehow I landed up with 100's of these cheap servos of all types and I would never use any of them. Unfortunately I have not seen a good quality miniature linear servo. if you can use linkages and a large sealed good quality servo outside it is great but it will be nice to see what you folks come up with. During the shows i had this animated bagger running and the servos kept dying on me every show, eventually I realized it was the pot. In the RC world the use of this servo so limited that it lasts along time, it may be OK for turnouts but anywhere there is frequent use like repeated animation the quality of the servo will make a big difference. Kim
Yeah, that is a valid point on their lifetime Kim. I was thinking the pot wipers might wear out easily. Solenoids would last longer but cannot give 3 positions. But if they had servos with optical encoders instead of pots they could last. I went ahead and ordered up a Chinese 50W fiber laser today so I can play around with making things like etched brass parts without using the chemical etch process, thinking I can get small durable parts. I might be able to make my own optical feedback based positioning mechanism.
The lifetime can be contolled. If you run these at a show, moving 50-100 times, OK. Some of the big issues for me was the Servos where mis-applied, meaning under powered for the app. Example try to throw hand-laid points, amplified with plastic versus metal gearing. This makes the Servo not reach its set point, so the driver keeps pinging, causing excess wear of the pot feedback. Some manufacturers noted that they have this durability but still - under powered. Tam Valley figured this out and stops the servo updates (to save the lifetime). Can you mount a standard servo pair under, that either be used ‘forever’ or possible ‘plug-n-play’ replacement “module”. After you make up a test linkage, sequencing the servos frequently should give some detail to possible lifetime.
That's going to keep you busy. I wanted to try thick AL foil, now you can build metal bases with power pickup or strong thin mechanical structures or make your own PCB and tracks... another long list of possibilities. Cant wait to see what all you come up with it. Kim
I watched a video of a guy who uses aluminum business cards to make foldable price tags for glass shelves with his Fiber Laser. It is amazingly fast and they fold easily, so aluminum foils are easy. Yes a long list of possibilities. Locomotive shells, tank cars, actually any kind of rail cars, etc. I just got to spend a little time defining material power, speed, and frequency recipe's, and fine tune all the distortion corrections out of the optics, and possibly play with different focus lens sizes to see how fine I can process. But, that's all part oft he fun of a NEW TOY. Then I will leak all the secrets to all the other laser kit guys, and they will jump on the fiber laser kit bandwagon too! This might even re-ignite the Z Scale modeling boom of 2004-2012 again. Remember all the new players who got into making cool Z Scale stuff back then? Kim's Art Shop, Hobo Tim, Stonebridge Models, Make My Model, LaZy Way Out Models, etc.? Remember all the Z Scale Conventions? It's time for another coming of Z!
Rob, You have a witness, amen! I looked at all those businesses on ZScaleMonster, and wonder what happened to them all? I still wish you wanted to sell kits again. I'm bummed I missed the boat. Scott
OK, so the bottom line on the model railroad industry is it's a labor of love, until it isn't. If you want to make a million dollars in model trains, start with 2 million dollars. What happens is people initially are excited that other people like what they are making, so they think to themselves, I am going to sell some to fund my hobby. But then the orders pour in, and you find yourself burdened and tied down making the same thing all the time, and you are really no richer, so you stop. This is called "Burnout". I first experienced burnout when every day I found myself in line for 45 minutes after work at the United States 3rd slowest post office. Then the declarations forms, I spent so much time filling them out to mail something over seas. So in phase 1 of burnout I stopped offering items to individuals, and began selling to hobby shops only. Phase 2 burnout was the hobby shops, 3 of these 2 of that 6 of the other, shop 1 of a dozen orders completed, next... So I only did Micro Trains Line kits for a couple years. But I found I was busy every day after work from 4PM till 10PM, and weekends for 12 hours a day, and I was making lots of kits but had no time to have fun. Then in 2012 I got a major promotion at my day job, and my workload increased as much as my salary. So I phase 3 burnout due to no sleep caused me to stop making kits, and instead I started funneling away 20% of my salary, and retired 9 years early. Initially I thought I was going to do kits again in retirement, but I found I am so busy with 7 grandkids and a dozen family outings a year, that I decided to not make kits again. I do trade my kits with others though, and if someone wanted a bunch of something, I can do that, but I really, really hate writing instructions for kits, often investing 40 hours or more just for 1 kit. So now my hobby time is hobby time again, and I want to focus on innovation, and share everything with everyone else. I have no trade secrets, and will share all I learn with anyone.
Z scale community is so small and fragile that when a company or an individual stops the production of any item - it's a big loss for everyone. I believe the future of this scale - are individual hobbyists and makers and not big companies like Märklin. I am not sure about AZL and MTL, but Märklin definetely realized - that Z scale market is very small - they hardly invest into the development of new models. The majority of their models are just reissues from the old days with minor improvements like new motors and sometimes controversial improvements like metal filled plastic (destroyed model details and look). Basically Märklin sells us 50 year old track and couplers from the 50 year old moulds at a high price. Whereas the demand for more true to life models has risen. And with the development of modern technologies like resin 3d printing and laser cutting we can produce better models which are true works of art. I have recently read about a drama with Gerard Huet's switchers and turnouts. I perfectly realize that one person can hardly run the mass production but I also wish the Z scale legacy could be preserved and saved. I would also like to thank you for the amazing job you have been doing by making these models. It's really important for the entire community.
I will say I’m getting my second wind again with Z. I can’t explain it but maybe it’s the AZL sw1500 that lit the spark. Got another on the way..But I’m getting an excitement from building vehicles working scenery deciding what or how to restructure new model. But watching your work Robert and others lately just keeps me checking for updates and inspiration.
A nice shelf layout with a city scene, lot's of warehouses with rail traffic, endless switching, and a couple of those SW1500's running around. Heck yes!
Hi Ray I , for one, miss your kits When I used to run the Centrebeam flats on Shasta at shows people were amazed when I told them how they were produced Still got them all, and the Covhops and Thrall door boxcars. Its making me want to get Shasta set up this weekend and give it a run Kev
What I am really sorry about Kev, is I never got your last order done. You had ordered a bunch of my newer Centerbeam cars, and I went off on a tangent updating all the previous version drawings with my latest design, which were both a bit easier to assemble and so, so very much more detailed and accurate. I had developed newer techniques from when you built previous versions, that I wanted them all updated. Anyways, that was about the time that my day job promotion and MTL kit burnout happened, so I never finished the decals. This was all the versions of Centerbeam Car kits I had up to that time, 19 different car bodies: Here is an example of the first Centerbeam car I designed, and the update version of the same car body: Original Release: The updated versions had lazerboard construction vs the old plywood in the original version, so surfaces painted up smoother and decals set flatter: Coupling was closer, and the car ends had perforated brake platforms: And I had perfected laser precut decals, so all you had to do for perfect decal application was set the decal sheet on wet paper towel, and pull off the decal sheet with sharp tweezers, and there was no using an exacto knife to cut out decals. Easy Peasy!
Those single sheet decals are a great idea. It certainly makes the job much easier. The cars are amazing. Jim
