This prototype circuit is a good example of how my design process works. The point at which I built this prototype was in the middle of the design process, and not the starting point. The customer already had an electronic design, and wanted to have a Printed Circuit Board made. So, I replicated the electronic design with the circuit design tool I was using at the time (OrCAD). Then generated the Printed Circuit Board layout. Once we had released the Gerber files for fabrication is when I decided to prototype the design while we were waiting on the fabricated Printed Circuit Boards.
My main concern is that we got all the connections that needed to be made hooked up correctly. There was one enable pin that needed to be hooked up in order for the circuit to work properly. I was able to stop the PCB Fabrication House before they printed the PCB, and get the extra connection added. The Printed Circuit Board worked the first time once we had received, and assembled it.
The operation of the circuit works like this. First is the oscillator is a Quad Op Amp, LM324, which is configured as a relaxation oscillator. The LM324 has four Op Amps in it, so I used one for the relaxation oscillator, and the other three as buffer amplifiers. The clock signal is then fed to a digital counter, CD4024, a seven bit binary counter, which takes an incoming pulse train, the clock, and counts the number of pulses. The output is in binary, and there are seven output pins for the seven bits. The high order bits (4, 5, and 6) are fed to the sequencers address bits. The sequencer is a MC14051 Analog Multiplexor. The address input bits select which output channel get connected to the source. So, when you input address bits in binary order they will switch the outputs in numeric order, the sequence. This could also be an arbitrary selection if you were to use a processor to drive the address inputs.
This prototype is typical for small electronic prototypes. I use single sided printed circuit boards with 100 mil hole spacing, and plated with a pad per hole layout. All the connections are made with discrete wires, in this case 26 AWG solid core wire. Not all the components have 100 mil spacing connections, and you wind up bending legs, and modifying the board as needed to accommodate the components. I have made hundreds of prototype bards similar to this to work out circuits, and do proof of concept work. This one is fun because it is visual with all the LEDs.
Ethanol claims another victim. Small engines generally do not like Ethanol. Cheap pump gas usually contains 10% to 15% Ethanol. Ethanol eats the seals inside these small carburetors. So, if you use cheap pump gas, and leave it in your small equipment continuously then eventually you will have a fuel system breakdown, and have to repair your small gas powered equipment.
In this case it is a Stihl MM55C Tiller. It is a good Tiller, but I don't use it very often. Generally I use it a lot in the springtime, then it sits there the rest of the year. Well, I left fuel in it over that time. One springtime when I went to use the Tiller it wouldn't start, and wouldn't crank either. I try to pull the cord, and the motor wouldn't move at all. Well, it had a hydrostatic lock. There was liquid fuel in the combustion chamber, and it wouldn't let the piston move up. So, I pulled the Spark Plug out to relieve the pressure, and it spewed liquid fuel out of the Spark Plug port. Then I realized that a seal had failed in the carburetor, and was letting liquid fuel get into the engine. Big Puppy Sigh...
So, this is pretty typical of small engines. The equipment is kind of old, a few, or more years. I had been thinking that I had been using "good" gas, Super, 92 octane, but it still has Ethanol in it. Small Engine Manufacturers usually will have a compatible fuel available for their equipment. Stihl makes Ethanol Free 2 Cycle Fuel for their equipment. It is expensive, but is it worth the time, and energy needed to repair a damaged fuel system? So, the Carburetor is well gunked up due to use, and years of sitting. Well start pulling the fuel system apart.
Stihl makes small engines very well. They have a clean design, and are simplified as much as possible. They take service well, and I can get parts fairly easily. There were three screws in the back cover, one screw in the fuel tank, one screw in the air cleaner, and two nuts held the carburetor on. All the fuel lines are press fit, and there is some tricky part shapes that make everything fit together when the screws are in. It is refreshingly simple.
The Fuel Tank is pretty icky, as usual. I bought all the fuel system parts, so we'll be replacing the fuel lines, fuel filter, and the carburetor. Generally I like to get a rebuild kit that has all the replacement parts for the carburetor, but in this case the only option was a replacement carburetor.
The Fuel Tank itself needs to be cleaned, not just to get the gunk off the outside, but also to flush out the old gas inside, and any particulates that have got into the Fuel Tank. So the Fuel Tank get a full kitchen dish washing with soap, and hot water. We want to totally flush out the Fuel Tank, and then let it dry out completely before re-assembling the Fuel System.
When re-assembling the Fuel Tank you can use some Silicon Spray to lubricate the press fitted Fuel Lines. A little Silicon Spray will help the Fuel Lines to go on easier, and then the Silicon Spray will dissipate into Silicon Hoses with no problem. It is certainly looking much better at this point.
Installing the new Carburetor is making my Small Engine look a little more complete. I salvaged the exterior gaskets from the old Carburetor. They seemed to be in marginal shape. I used a little more Silicon Spray when I installed the Fuel Lines on the Carburetor.
Something I noticed is this Carburetor doesn't have a Choke Valve in the Carburetor. The Choke Valve is integrated into the Air Cleaner Assembly, and is all plastic. I'm not sure of the reason why it is like this, but I'll assume it is another way to simplify the design, and possibly reduce cost. It is neat, anyway.
Once it was all back together I double check my work, then gassed it up, and gave it a krank. I spent a little time tuning the mixture screws, and my little MM55C is working again. Lets go rip some dirt...
In my FR-S, Ripper, the Cup Holder wound up in an unfortunate location. The Cup Holders are where the Arm Rest should be. They are right behind the shifter, and emergency brake, precisely in the path of my elbow when I am shifting into even gears. Yeah, I know there is limited space in the FR-S, and they had to do what they could to get a couple Cup Holders in there. But, yeah, not the best place. The Cup Holders work a lot better as Coin Cups, or maybe a Cup of Chile Con Queso, LOL!
So, what to do... What to do... Let's fabricate some auxiliary Cup Holders. Did you know that you can order Black PVC from Home Depot? You can get pipe, and sheets. So I wanted these auxiliary Cup Holders to accommodate all my needs, away from the center console. There are pockets in the doors that will hold a bottle, but not upright, so they need sealing lids. I usually carry water, and coffee, plus I need an ashtray. So, we need three holders. The diameters of the things I want to hold are all a little less than three inches. I picked three inch inside diameter black PVC Tube. Then to hold them all together I got a sheet of black PVC quarter inch thick.
The neat thing about PVC is that it can be glued together very effectively. This eliminates a lot of hardware that would have potentially been there. The PVC Tubes were cut to appropriate lengths for the things I wanted to hold, and then glued to part of the Sheet PVC. I had to angle the water bottle a little to clear the Glove Box Door. Then the PVC Sheet is connected to a center console panel with a couple machine screws. The center console panel then gets connected to the center console with snap clips, four of them, and it has a secure fit. This gets all of the things I want to hold out of the way of my elbow, yet still within a reasonable reach. The Cup Holders only protrude into the passenger space by about four inches, so, not too bad, LOL!
Being my first time to re-upholster a leather seat it took some time to figure out how this stuff works. In retrospect it's logical, and when the seat goes back together you get why all the things within the seat are the way they are. All the things within the seat work to make the finished look, feel, and functionality of the seat suit a need as a automotive seat. You have creature comfort factors, anti-fatigue factors, safety factors, and most important some would say, looks...
A luxury car is supposed to have good looking everything. The seats get scrutinized extra closely because you are in direct contact with them. Well, after my RX300 got used as a work truck for more than a decade the driver seat was looking terrible. The front passenger seat is not nearly so bad, and the back seats are hardly used because they are furled most of the time. So the big final task that I had with the drivers seat was to remove the seat back skin from the replacement seat. That means I had to totally disassemble another seat just to get the seat back skin.
I bought this replacement seat from a salvage yard to use in the RX300 while I was re-conditioning the original seat. This took a lot longer than I expected. So, above, is the replacement seat, disassembled, so that I could get the seat back skin. Doing this for the second time took considerably less time, now that I know the construction of this seat.
I pulled both the front seats out of the RX300 which gave me an opportunity to do some deep cleaning. I found a sub-woofer under the front passenger seat which I did not know was there. This RX300 has the Premium Sound. Having the seats removed allowed me to access a lot of areas I couldn't clean with the seats installed. The whole passenger compartment is a lot cleaner now.
This is the seat back heater. It is a lot simpler that the seat bottom heater. It was easier to remove from the old seat skin, and easier to apply to the new seat skin. It was a non-issue with the experience that I gleaned from re-upholstering the seat bottom. Re-installing the Hog Rings in the seat back was also a lot easier now that I had a little experience with it. Hog Rings work in a very specific way, and once you work with them a little you pick up their tricks.
This is one of my favorite features of the RX300 seat, above, the Lumbar Adjustment. Over the years I had imagined how the Lumbar Adjustment works, and this isn't what I was thinking. The way it does work is pretty logical. There is a gear reduction motor that drives a crossbar into the Lumbar area of the seat. When you push the control one way it drives this bar into your lower back, pushing the Lumbar Adjustment out. When you push the control the other way it drives the Lumbar Adjustment back into the seat. It is neat, and it is one of my favorite features of the RX300 seats.
OK, now the original seat is back in the RX300, with new leather seat skins, and it looks great. The seat heater, as well as all the electromechanical controls all work. The new seat bottom skin is a little off color, but that is a lot better that shredded seat skins covered with duct tape. Plus I got to deep clean most of the passenger compartment, so it feels a lot better inside the RX300 now...
So I bought an aftermarket replacement seat skin for my RX300 driver seat. In theory this is the correct repair. They original seat skin was destroyed, and you should replace the damaged part, not cover it up. There are a lot of cheap over-cover type seat covers. I think they all look terrible because they don't fit correctly, and slip around when you sit on them. The correct course of action here is to replace the original seat skin with a proper replacement part.
Now this was not at all as easy as I had imagined. First the new, leather seat skin is fitted to the seat cushion, which means when it is installed it will be very tight. This leaves no room for getting the seat skin on to the seat. The seat skin needs to be stretched before it is installed on the seat, and then it can relax to fit the seat tightly. Typically a upholstery shop is going to use steam to warm up the seat cover, make it more pliable, and be able to stretch the seat skin fairly easily to install the seat cover. Well, one tool that I did not have was the steam gun, and it made this job a lot more difficult.
Another aspect to this task was to install the seat heater in the new seat skin. The seat heater is a simple fabric form that holds a heater wire. This wire snakes around the area of the seat cover where you are making contact with the seat. It is a single contiguous wire that runs around the area of the seat cover. The heater is attached to the seat cover with a spray adhesive, so it was fairly simple to remove it from the old seat cover.
I picked a medium strength spray adhesive from the hardware store to install the seat heater in the new seat cover. Above you can see the spray adhesive, the Hog Ring Pliers, and Hog Rings. I had some difficulty finding the Hog Rings. They are not standard hardware store hardware, and I had to get them from the Interwebz. So, I positioned the seat heater in the new seat cover, and adhered it in sections, carefully. I also made sure that it was fully adhered to the seat cover before trying to install the seat cover.
You are really going to wrestle with the seat skin to get it on to the seat, and you don't want the seat heater slipping around under the seat cover when you are trying to install it. Now for the Hog Rings. The Hog Rings are what pulls the seat cover down into the seat cushion. This makes that nice fitment, and prevents the seat cover from slipping around on top of the seat. Hog Rings are the hardware that holds upholstery together. The seat itself is a wire frame, springs, and foam cushions. The Hog Rings hold the seat cover on to the seat. Some of these Hog Rings are in very difficult places to access, especially the deep crevices in the middle of the seat. It took a lot of strength, and patients to get these Hog Rings in there. Also, I had a lot of misfires because this is my first time installing Hog Rings. I probably used 20 Hog Rings to install 8.
So, I did get the new seat cover installed. Is it perfect? No... It's my first leather upholstery experience, and I learned a lot with this experience. It does look a lot better that the mess that the old seat cover was. I really need the steam tool to make it look better. When you pull off the old seat cover you should steam the seat cushions to revitalize them a little. Then you need to steam the new seat cover before you try to install it. With the steam you should get much better fitment. OK, the next step in this process it to remove the seat back cover from the replacement seat in the RX300. Then I'll install the seat back heater from the original seat into the seat back cover from the replacement seat. Then I'll install the replacement seat back cover, and heater from the original seat on to the original seat from the RX300. Are you following? The end result will be the original seat from the RX300 will have new seat skins, and look a lot better than it has looked lately.
Leather seats require regular maintenance. The leather needs a conditioner so it is able to maintain it's elasticity. When it is elastic, pliable it can move with the stresses that are applied to it. If you don't condition your leather seats the leather will become hard, and crack when stresses are applied to it. Well, my RX300 was assigned to be my work truck, and the "frilly" maintenance like leather conditioning took a low priority. Well, eventually this took a heavy toll on the drivers seat.
As the leather got dried out, cracks started to form, and the cracks turned into tears, and so on. My solution at the time was to cover the tears with duct tape, LOL! Then the duct tape started to build up. The seat kept getting harder, and less comfortable. This came to an apex in the summer of 2019? maybe... So, I found another seat from a salvage yard, pulled this seat out of the RX300, and replaced it with the salvage seat. Then the original seat spent a few years sitting around my house.
For a while it was consigned to the patio, and it has become very dirty because of the weather. These leather seats were never intended to be exposed to the weather directly. The replacement seat that is in the RX300 now does not have a seat heater. That is one of my favorite features of the RX300. Mainly for my back, the seat heater, in conjunction with the lumbar support, are my favorite creature comforts in the RX300. So, now I want to refurbish the original RX300 seat to get my seat heaters back.
The part of this seat with the biggest issues is the bottom part of the seat, the actual seat part. The dried, cracked leather is not salvageable. It's covered with duct tape, and the tears under the duct tape are significant. The thing to do is to get a replacement skin, and completely replace the leather cover. Typically a piece of leather like this might be a couple hundred dollars. But, this is a 20 year old truck, and we can find discounted, or clearance items that will do. The one I found, and ordered was $62.
The back of the seat is in a little better condition, but the leather is very dried out, and cracking. This part I did try to re-condition. I spent a few hours cleaning, and conditioning the seat back, and head rest. The head rest was the least damaged part. After hours of hand scrubbing the leather I only have marginal results, and I'm not really happy with it. The head rest looks OK, but the seat back still looks pretty terrible.
So, I've hatched a plan. I have a new seat bottom leather skin on order. That will look great, brand new. I don't want to pair the new seat bottom with the grungy looking seat back. But, we have some more parts. I have the replacement seat from the salvage yard. It's seat back looks great, almost brand new, but it doesn't have the seat heater. What I have to do is remove the leather skin from the salvage seat back, and then install it on the original seat that has the heater. This is labor intensive, but I think it will be worth it in the end. Doing upholstery is hand intensive, hard work. The Hog Rings that hold the upholstery together are usually deeply buried within the seats, and it is difficult to get them. But, as I progress in this project the Hog Rings are becoming familiar. I have to get a Hog Ring Pliers, and a supply of Hog Rings to do the re-assembly. I'm looking forward to getting my replacement parts...
Cedar is pretty wood. It smells nice. You can cook with it, like Cedar Plank Smoked Salmon. What do you not do with Cedar? You don't use it as fence posts. My Old Fence... Yeah, Cedar Posts... On the Southgate the Latch side post has been broken, at the base, for maybe a year. I used some old fence parts to shore it up, and keep it from moving. Then I got tired of not being able to use Southgate. It's my direct access to the front yard, and the mailbox, so I had motivation to fix it. Removing the post, gate latch, and a little stub of fence that was there was easy. I simply removed my reinforcements, picked up, and carried it away. The Concrete Slug in the ground was another matter altogether.
Sometimes I call these stumps, which isn't really the correct term, meaning there is something left above the ground. Slug is a better term because it is this massive, sometimes more than a hundred pounds, chunk of concrete which is buried in the Texas Clay Soil. Sometimes I get a break, and there is a solid piece of wood that I can drive a big Eye Screw into so that I can get a handle on it. In this case the remainder of the Cedar Post was completely rotted. I was able to pull it apart with my hands like it was Pot Roast, and it was fibrous like that. Slow cooked Cedar Post anyone?
When I do repairs on my fence I am going to re-double the strength of what was there originally. I am also going to use superior building materials. I am replacing a 4X4 Post with a 6X6 Post, which more that doubles it's area. These posts are Yellawood, which is pressure treated Pine which is rated for ground contact. Cedar is insect resistant, but it is a really soft wood, and is not intended to be a load bearing, structural piece, like a post. By using the pressure treated wood I can continue the natural look of a wooden fence, but get the superior weather resistance, and structural integrity of engineered wood.
The next step is to secure it, which means more concrete. This hole took almost two bags of concrete, maybe around 110 pounds. I've developed a technique mixing concrete in a contractor bucket using a Sharp Shooter Space to mix it. It's a Do what you can with what you got scheme. I've been using this technique for several years, and it works good. I have also evolved my Post Hole preparation technique.
At one time I was using concrete forms to shape the concrete slugs. Don't do that. Concrete forms make you dig the hole too wide to get the form in. Then you have to back fill around the outside of the concrete form to fill in the air space left. This leaves weak spots in the soil around the concrete slug which will cause your post to shift out of plumb. Fence posts that are not straight, not plumb, look terrible. Now, as I dig the post hole, I use the sides of the hole as the fulcrum for my digging lever, the Sharp Shooter Spade. This compresses the soil around the upper part of the hole, and makes the footing for your fence post more solid. When you pour the concrete, let it set, and then cure the new fence post will be very solidly secured, and will not move. I've used this technique with the last thirteen posts I've set, and they are all doing well.
The next piece of the fence I am going to work on is the Gate. Sure, now the gate can be opened, closed, latched, and locked. But, it is 20 year old Cedar, and kinda floppy. Another thing is the design of the gate. It has no frame. There are two 2X4 pieces attached to the hinges, and then every thing else is attached to those 2X4s. I am astounded that it lasted 20 years. This is the next project...
