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Money Donation Machine - My son's Eagle Scout Service Project
[As this article relates to my son's Eagle Scout service project, I wrote most of it, but he had editorial discretion and added some content in various places. In the article, "I" refers to Scott, and "he" refers to Aiden, my son.]
About 9 years ago, my wife and I decided that we wanted to impart a sense of giving back to our son, so we decided to start volunteering with Feeding San Diego. We've been regular volunteers since, and when the opportunity arose to become trained as Team Leaders, we did so and our son, Aiden, at age 10 became the youngest team leader.
When it came time in August 2020 for Aiden to start planning his Eagle Scout service project, he wanted to do something for Feeding San Diego. He brainstormed with their marketing department, and they decided on a cash donation machine similar to ones at science museums and children's museums, which suck the money up through a series of clear tubes. Aiden went back and forth with them over the course of many months to come up with a design and get it approved. While ironing out the design, he started figuring out the actual mechanics of how it would work. I was as hands off on the project as possible, but gave some suggestions here and there. While this donation machine won't be handling million dollar donations, it will hopefully encourage people to donate, and be used as a talking piece in their lobby.
He started his concept using an open source project he found, but it didn't quite meet his needs. The first part was to be able to turn on a vacuum when some type of trigger (more on that later) was activated. I prototyped using a WiFi outlet and a WEMOS D1 Mini, but didn't tell him how I did it just to give myself confidence that it could be done. It was a pretty simple concept where I setup the WEMOS as a WiFi access point and had the outlet connect to it; when a button was pressed, the WEMOS (basically an Arduino) sent an HTTP command to the outlet running Tasmota firmware. This concept was great, but in the end there was too much wireless interference when Aiden installed the project for it to actually work. Luckily Aiden found a UL listed wired switch called the Dataprobe iBoot-IO. This product was quite expensive, but turned out to be reliable and met our requirement of being UL listed.
After getting the outlet to trigger, the next piece was how should it trigger? Basically, when money is put in the tube, it breaks an infrared beam and sends a signal to the outlet. This was completely out of my scope of knowledge, so Aiden did some research, figured out how to wire an IR sensor and receiver. The schematic is below. With that out of the way, how was it going to be mounted? Aiden has become a pro at using Fusion 360 and designed a ring to house the electronics and fit around the tubing. As part of programming the sensors, Aiden wrote the Arduino code to turn off the outlet after a certain number of seconds to allow the money to go through the series of tubes.
Is the project done, yet? I kept asking myself that numerous times over the 10 months of the project! Feeding San Diego wanted to make the cabinet to house the vacuum, electronics and collect the money, so Aiden designed and provided the dimensions for the box (again using Fusion 360). Unfortunately, the box wasn't made to those dimensions, but that turned out to be a good thing. The box had a compartment for the vacuum and then a top compartment where the money would go that had a window for people to see. Aiden's assumption on the box is that the top part would be completely sealed such that the vacuum could be attached to the bottom and there would be enough suction to draw the money through the tubes. I wasn't, however, convinced of this and suggested that Aiden have a backup plan. I gave him an idea of a flap on the end of the tube that would close when the vacuum was turned on (the vacuum would provide enough suction to close the flap). Unfortunately the vacuum didn't do that, so Aiden expanded on the idea and designed a flap with a servo such that his program sent a command to the servo to close the flap when the vacuum was turned on and then opened the flap when the vacuum was turned off so that the money would just drop.
With that finished, Aiden was confident that everything would work when installed. A few days before he installed the project, we were able to pick up the box so that Aiden could prepare it by installing thick foam to deaden the sound of the vacuum. When install day came around, Aiden led a number of Scouts and adults from his troop on attaching it to the wall. At the end when it came time to turn on the machine, the wireless interference I mentioned before caused problems with it not being reliable. After trying to troubleshoot it, Aiden finally found the iBoot IO box and ordered it as that would be more reliable and he wouldn't have to worry about it. Waiting for the part, however, was torturous for him.
Once the part arrived, we went back to Feeding San Diego and he installed it. The electronics worked well and did what it was supposed to do. Unfortunately, there was another hiccup and that was that if the money wasn't crumpled, it wouldn't make it through the tubes. Back to Fusion 360 to design a "cap" to make the hole smaller and require people to crumple the money (signage has been added). Was that the final piece in making everything work? No. Turns out the vacuum was a bit underpowered, and the money wouldn't always make it through even if it was crumpled. More research and a trip to Home Depot for a larger vacuum got him one step closer. Remember I mentioned the larger box before? The new vacuum was larger and some of the insulation he put in had to be cut out to accommodate it.
Was he done after the new vacuum? Well, almost. Aiden didn't follow the KISS principle in his code which caused some false activations on the vacuum. I encouraged him to remove extra code and just turn on and off the outlet when the sensor was tripped; he had code in there that attempted to detect if someone kept triggering the vacuum and was playing around. That code, unfortunately, was a bit too complex for this application.
Does it work? Yes!
Aiden wanted me to write up his project and I've done my best to capture the big pieces.
If you have any questions about this, please don't hesitate to contact me.
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Website Monitoring using Home Assistant and Node-RED
Recently I was asked by a Scout unit to try to let them know when an event was available for signup. While there are sites that allow you to do this, I didn't want to have to signup for another site so I decided to figure out how to get Home Assistant to notify me of changes. I've written in the past about using Node-RED with Home Assistant and while Home Assistant has made it easier to create automations without having to use YAML, I still find that Node-RED is a much cleaner and simpler way of creating and viewing automations.
So I started trying to figure out how to get Node-RED to check websites and notify me. Turns out the process was pretty easy.
- Add
node-red-contrib-object-hashto Node-RED's configuration. - Tell Node-RED to do an HTTP GET on each site once an hour.
- Take the result of the HTTP GET and perform a hash on the results.
- Create a Home Assistant sensor using MQTT with the URL and the hash in it.
- Wait for a change in the hash and then notify me of the change (I use Slack right now).
It's a pretty simple slow and the downsides are that there is a slim chance that a change would trigger a hash change (hash collisions are possible, but rare) and it doesn't tell me what the change actually is.
I'm sure there are other ways to monitor sites, but I don't have to rely on others for this. While the notification uses Slack, I can switch out the notification to any other method.
You can download the flow here.
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Review: Ender 3 Direct Drive Upgrade Kit
I’ve been 3D printing for about 3 years now and anyone that has taken up this hobby knows that there is a lot of fiddling and tweaking to get the kind of prints you want. When I bought my Ender 3 Pro, I knew I wouldn’t be satisfied with the stock printer as I had read about so many nifty little upgrades. Over the years I’ve added things like an EZRStuder, a glass bed, a filament holder with bearings, a Capricon Bowden Tube, etc. With these upgrades, I’ve been pretty successful at printing PETG, PLA, and TPU filament. Since most of my prints these days are functional prints, I really haven’t tuned the printer for the best quality.
This summer I went to print some battery caps for my Ryobi batteries out of Sainsmart TPU like I had done many times and had the hardest time getting it to print well. I replaced the Bowden tube, used a glue stick to get the print to stick, changed settings in Cura, and various other things I could think of really to no avail. I was so frustrated that I ordered an Ender 3 Direct Drive Upgrade Kit and thought that it would solve all my problems. After reading a bit more about this and how it could lead to other problems due to the weight on the gantry, I cancelled my order and just lived with the mediocre prints.
Ryobi Battery CapA few weeks ago after reading in the Reddit forums, I decided to give the upgrade kit another try. It arrived pretty quickly, but I had to wait to install and set it up. Installation was a breeze, but it turns out that I made enough changes to the printer that the prints (even with regular PLA filament) turned out poorly. I tried to tune my Cura settings, but that didn’t help. I went back and tightened the belts, the eccentric nuts, re-leveled the bed, changed the nozzle, reset the Z probe offset, and finally got some decent prints.
After all that work, I went ahead and started printing various pieces in PLA, TPU 95 and TPU 85. All of the pieces came out good enough for what I needed. I still can fine tune the Cura settings, but the direct drive has allowed me to print faster with fewer problems. Since it is cold in my garage where my printer is, I decided to forego the PEI bed I’ve been using and simply use a glass bed with a glue stick.
The direct drive upgrade has gotten me thinking about an Ender S1 Pro printer. However, it is really hard to justify that kind of money when I don’t print that often. The $30 I spent on the direct drive upgrade was a much better investment because a new printer would bring different issues and would still require me to fine tune various aspects of it.
Installed Direct DrivePros
- Inexpensive upgrade
- Easy to install
- Easier to print flexible filaments
- Eliminates Bowden tube issues
Cons
- Requires tuning the printer again
- Extra weight on gantry could cause quality issues with prints
- Still has a piece of tubing between the extruder and the hotend (could get clogged)
Summary
If you have an Ender 3 printer, this upgrade is a no brainer. Even if you don’t print flexible filaments, it is so much easier to print with PLA when the filament goes directly into the hot end. Of all the upgrades I’ve done to my printer, this may have given me the most bang for the buck. If I had gotten this before, I could have passed on the EZRStruder and the Capricorn tubing.
One caution if you do get this and that is that it may take some time to tune the printer back to the way it was. It took me about 5 hours to get prints working again.
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Review: LED Headlamp
I've written in the past about having a variety of flashlights and when I came across this headlamp, I had to give it a try. I actually stumbled upon it from a spammy ad for a similar product; given that there were a number of products that looked identical, I decided to purchase the cheapest with the idea that they all came from the same factory and I was probably correct.
Lately I've been walking the dog when it is dark (I've run out of time during the day and the dog needs a walk), so I was interested in what would make it easier to see at night. I found that other headlamps were uncomfortable and were very directional with a very narrow beam. While some people swear by headlamps for camping and other activities, I've avoided them as much as possible as I found a flashlight to be easier to light my way.
This headlamp differs from other headlamps in that the main light is a strip of LEDs across the front and weighs significantly less than other lights. I've used it on a few walks and was amazed at how bright it was and how much it lit the path. There is a gimmicky feature on it that lets you wave your hand on the side of the light to turn it on and off (kind of like wax on/wax off). Turns out it is actually useful! My walk isn't in the complete dark, so I was easily able to turn the light off when not needed. However, the sensor is quite sensitive so if you're using it in an enclosed space, it will likely turn on and off as you move.
I haven't had a chance to see how long it lasts, so I can't confirm the runtime. It does charge pretty quickly over USB-C. Well, sort of. I was intrigued about USB-C charging so I connected a USB-C to USB-C cable to 2 different chargers and it didn't charge. The headlamp uses a USB-C connector, but doesn't actually use USB-C (it comes with a USB-A to USB-C cable for charging). That's a bit disappointing as I have to bring a different cable if I go camping.
Pros
- Light weight
- Wide beam
Cons
- Doesn't use real USB-C charging
- Hand waving sensor is gimmicky
Summary
This inexpensive headlamp is well worth the $10 I paid for it. While I hope that it lasts, I have no idea the longevity of it. I'm excited to take it on my next camping trip. While I would have designed it differently by removing the side sensor, putting the battery in the back and getting rid of the light on the side, it is good enough for my needs.