Yanmis YF-7 two-relay timer

I bought a Yanmis YF-7 from Amazon about a month ago and am finally getting around to playing with it. It can be powered by a 9V battery and has a programmable timer for controlling two on-board relays.

[EDIT: Unit failed. I had it in a drawer for a few months, took it out to try using it and it won’t turn on. It just heats up like it has a short (none visible) and nothing is connected to it besides a 9V battery. Sadness is mine.]

The main problem I’ve found so far is that there is no documentation for it. They sent no manual with it, and an internet search yielded just a tiny amount of information from the German Amazon website, and then from competitor’s models that have similar programming. They did say that I could email them for a manual, but I don’t like giving a live email address out. I’d much prefer that they had a link for downloading a PDF manual.
Click here for a PDF of this document

So, I will post what I find here, and try to keep it updated with the latest information.

YANMIS YF-7 USER GUIDE by W. Jason Woodrow 2019

Yanmis YF-7
Part Number: Yanmisepv0txaurd
UPC: 746771544984
Description: Multifunctional Delay Relay, DC 7-30V

9V model buttons

The unit can be powered by a single 9V battery. The unit has two relays each with a red LED on the board that indicates which one is currently powered. They operate independently, and can operate simultaneously depending on programming.

When the unit is powered-on, by default it will display dashes on the LED display “- – – -” meaning all timers have run out of time.

The buttons at the bottom are K1, K2, K3, K4.

K1 held for 1 full second will enter program mode.
In Program mode, P will blink in the leftmost column. Choose which program you want, based on the number. P-##. Lowest ## is 11, highest is 48.
Settings are saved as they are made.

P: choose program from 11-18, 21-28, 31-38, 41-48 (excluding 19, 20, 29, 30, 39, 40), 32 programs total (although there are 3 that appear to be duplicates of others).

K2 increments the left digit
K3 increments the right digit
K4 decrements the right digit
Holding any of the these buttons cycles through the numbers

A timer (controls Relay 1)
B timer (often controls Relay 1)
C timer (controls Relay 2)
D timer (often controls Relay 2)

In program mode, press K1 briefly to display the A timer. See the chart below describing how the decimal affects the time. Press K1 briefly again to show B timer, etc. D timer is the last setting.

When display shows four dashes “- – – -” you have exited program mode and saved the settings. To enter Program mode again, press and hold K1 for one full second.

NOTE: In timer mode (A, b, C, d) K4 moves the location of the decimal or removes it. K2 increments all three digits, K3 decrements all three digits. Holding K2 or K3 cycles through the digits.

This part is a little confusing, and it can affect the way the other timers are interpreted by the device. If you stick to one method for all the timers, you’ll get the most consistent results.

A004. (decimal showing after last digit) is 4 minutes (Range is 1 to 999 minutes)
A004 (no decimal showing) is 4 seconds (Range is 1 to 999 seconds [16min 39sec])
A04.0 is 4 seconds (Range is 0.1 to 99.9 seconds [1min 39.9sec])
A4.00 is 4 seconds (Range is 0.01 to 9.99 seconds)

Through testing each mode, I was able to figure out if it started the timer based on power-on, trigger pulse high, trigger pulse low, or trigger steady power. A couple of modes were too odd to completely figure out.

For Triggers, I used a wire to feed from the negative power input to the two triggers (called Signals in the picture).

P-11: Trigger 1 keeps Relay 1 activated as long as trigger power remains. Same for Trigger 2 and Relay 2. Timers are not used.

P-12: Each trigger toggles the relay closed or open as many times as triggered. Timers have no function

P-13: Trigger 1 closes relay 1 for time set on timer A. Trigger 2 closes relay 2 for time set on timer C. B and D timers have no function.

P-14: appears to be the same as P-13

P-15: appears to be the same as P-13

P-16: appears to be the same as P-13

P-17: appears to be the same as P-13, except that the timer only shows “—-” (4 dashes)

P-18: Triggers inactive, Timers A & C start at power-on.

P-21: Trigger 1 runs Timer A then closes Relay 1 until power-off. (Trigger 1 can run timer again, but relay remains open until power-off).
Trigger 2 runs Timer C then closes Relay 2 until power-off.

P-22: Similar to P-21, except power to triggers have to remain on (cannot be a pulse). Timer will reset if trigger loses power.

P-23: Pulse to Trigger 1 runs Timer A then activates relay 1 until next trigger pulse which powers off relay 1 and starts timer A again. (Relay is off while timer runs, relay activates when timer reaches 0).
Pulse to Trigger 2 runs Timer C then activates Relay 2 until next trigger pulse which powers off Relay 2 and starts Timer C again.

P-24: Trigger 1 power must stay on, runs Timer A then activates relay. When Trigger 1 goes low, Timer A runs for time set on B and then closes relay. HOWEVER, see note below.

Trigger 2 power must stay on, runs Timer C then activates relay. When Trigger 2 goes low, Timer C runs for time set on D and then closes relay. HOWEVER, see note below.

HOWEVER, it also depends on how decimal is set on timers A and C.
A04.0 B07.0 C02.0 D03.0
A runs for 4 seconds, then runs for 7 seconds (Timer shows A during 2nd time)
C runs for 2 seconds, then runs for 3 seconds (Timer shows C during 2nd time)

A4.00 B07.0 C02.0 D03.0
A runs for 4 seconds, then runs for 0.7 sec, so it is like decimal was moved on B to B0.70
C runs for 2 seconds, then runs for 3 seconds (Timer shows C during 2nd time)

P-25: Toggle. Trigger 1 power must stay on, runs Timer A then activates relay. Stays activated when Trigger 1 goes low. Trigger 1 power must stay on, runs Timer A then deactivates relay.
(Same for Trigger 2 and Timer C)

P-26: Any change of state to Trigger 1 starts Timer A. If power to Trigger 1 is left on, Timer A will trigger when power is removed from Trigger 1. Or trigger can be pulsed with same effect.
Same for Trigger 2 and Timer C.

P-27: Same as P-23

P-28: Power on starts Timer A, then Timer C, Relay 2 activated, Timer A again, then Relay 1 activated. Relays stay activated until power-off. Triggers no effect. (I don’t understand this one’s purpose)

P-31: At power-on both relays activate, runs timers A, C, deactivates Relay 2, A, D, deactivates Relay 1, B, D, B, D, activates Relay 2, B, C, deactivates relay 2, B, activates Relay 1, D, A, C, A, D…. (I don’t understand the purpose of this one)

P-32: Loop. Trigger 1 power must stay on, activates Relay 1 runs Timer A, then deactivates Relay 1 while Timer B runs. Loops as long as power is on trigger.
Same for Trigger 2 and Timer C and D.

P-33: Loop. Same as P-32 BUT only needs a pulse for trigger. Next pulse to trigger cancels timers. Trigger 1 pulse activates Relay 1 runs Timer A, then deactivates Relay 1 while Timer B runs.
Same for Trigger 2 and Timer C and D.

P-34: Similar to P-31, except after activating and deactivating both timers, it stops. Triggers inactive.

P-35: Pulse to Trigger 1 starts timer A, then Relay 1 activates with Timer B, then stops until next trigger.
Same for Trigger 2 and Timer C and D.

P-36: Same as P-35, but Trigger power must remain on.

P-37: Pulse to Trigger 1 starts timer A and activates Relay 1, Timer B starts and Relay 1 deactivates, then stops until next trigger.
Same for Trigger 2 and Timer C and D.

P-38: Pulse to Trigger 1 starts timer A and activates Relay 1, Timer B starts and Relay 1 deactivates, Timer A repeats once more and activates Relay 1, then stops until next trigger.
Same for Trigger 2 and Timer C and D.

P-41: Trigger 1 goes LOW, Timer A starts and Relay 1 activates. Stops when Timer A finishes.
Same for Trigger 2, Timer C and Relay 2.

P-42: Trigger 1 goes LOW, Timer A starts. Timer B starts and Relay 1 activates. Stops when Timer B finishes.
Trigger 2 goes LOW, Timer C starts. Timer D starts and Relay 2 activates. Stops when Timer D finishes.

P-43: Same as P-42

P-44: Nothing seems to happen at all.

P-45: Power-on Relay 1 on for Timer A, then Relay 2 on for Timer B. Stops after Timer B.
Triggers not effective.

P-46: Trigger 1 HIGH, Relay 1 on for Timer A, then Relay 2 on for Timer B. Stops after Timer B.
Trigger 2 not effective.

P-47: Same as P-46.

P-48: Loop. Power-on Timer A on and Relay 1 activates, Relay 1 deactivates for Timer B. Timer C on and Relay 2 activates, Relay 2 deactivates for Timer D. Keeps doing this.

Work knives

I usually carry a knife at work as one of many tools. My last knife was a CRKT M16-12Z tanto style with serration near the handle. It served me well for many years until I used it to clean embedded moss from underneath my roof shingles. Before I realized what was happening, I had a nice fold-out butter knife. The abrasive shingles had ground away so much metal that the knife was just about useless.
knife damage

I talked to coworkers about knives they use, and two names stood out: Benchmade and Kershaw. I opted first to get a Benchmade Mini-Griptillian (blade alloy is 154CM). The lock on this knife was different than the CRKT, and the clip was oriented in the opposite direction (anchored on the butt of the handle). I carried it for about a month and it took some getting used-to having the knife in a different orientation than I had carried for years. But the blade was very sharp, and kept its edge well. It was smaller than I really liked, but had a good feeling handle. Another difference that I didn’t like was that it opened with just a thumb post, and had no index finger post.

Eventually, I found myself wanting a larger knife, and one that was oriented like my old CRKT. I looked at the Kershaw blades. I bought two, as they are far cheaper than the Benchmade. I bought a “Blur” and a “Clash” (blade alloy is Sandvik 14C28N).


I really like the shape of the Blur. It is pretty, a good size for my hand, and opens easily. The part I don’t like is that it only has a thumb post for opening. I also liked that the clip is anchored near the blade. This make drawing and opening the knife quicker and more natural for me than the other orientation.

The Clash is a similar knife, not as pretty to my eyes, but has an index finger post for opening. That makes it more natural for me, since my CRKT had both kinds of openers, and I used the index opener.

I find that the thumb posts invariably etch a hole in my pants. On my old knife, I took it to a grinder and removed about half of the thumb post on each side. I did something similar to one side of the Blur.

My ideal knife would be the Kershaw Blur with an index finger opener instead of a thumb post. I like the S30V version for the steel, but prefer a black blade.

The glass break on the butt of the Blur is a nice addition, which I wish were on the Clash. I’ve not seen anything online about retro-fitting a glass breaker.

I’ve chosen to carry the Clash, due to the opener and the orientation of the clip. The blade holds an edge well, perhaps not as well as the Benchmade which is made of a better alloy.

The assisted opening on the Kershaws is a nice feature when I’m in tight spaces, often up in a ceiling doing cabling work.

I use a small EZE LAP diamond stone to keep the edge and tip nice and sharp.

NOTE: One potentially dangerous part of the Clash is the way the blade locks with a “locking liner”. The vast majority of the time, this works very well. I was recently using the knife to clean out some fireproof foam from a pipe, and occasionally putting pressure on the BACK of the blade. Due to my grip touching the locking liner, the blade became free to close. I wasn’t injured, but it did get my attention. This kind of locking mechanism demands that the blade only be used with pressure on the sharp side until you intend to close the blade.

Garage Door Opener Radio Interference (and fix)

Our garage openers are both Linear LDO50 which uses 318MHz frequency for the receiver, and are about 12 years old. The security type is “MegaCode”.

We live directly across from a major airport, and not far from a smaller airport, so we typically get a LOT of radio interference with our garage openers. I can often see the receive indicator on the openers glowing solid red, or blinking rapidly for several seconds at a time. This causes the door to open slightly and then stop, and this repeats several times. Some days I just had to get out of the car and use a key to get in through a side door. The wall buttons for the openers always work, so I know there is no physical issue with the openers.

So I decided to try adding a new receiver that uses “Security+ 2.0” and 3 simultaneous frequencies (310/315/390MHz) since it is unlikely that all 3 will be getting interference at the same moment.

I bought the Liftmaster 850LM receiver that can control up to 3 openers. I also bought the compatible Liftmaster 892LT two-button remote controls.
NOTE: The remotes are able to use three different modes, and you must choose which one you will use.

1. I first set each remote control to use Security+ 2.0 instead of just 315Mhz or 390MHz.
Remote control

2. I plugged-in the receiver and pressed the Learn button for Channel 1 until the yellow LED turned on. I then pressed the left button of the first remote control to associate it with Channel 1 of the receiver. I repeated the process for the second remote. (Channel 1 can support up to 50 different remote controls! Channel 2 & 3 can each support up to 20 remote controls.) I then did the same for Channel 2, this time using the 2nd button on the remote.

3. I attached the receiver to the angle iron that holds the first garage door opener motor. I plugged in the power adapter and tied up the slack in the wires.
1st unit wiring

4. I used common telephone cable to do the wiring. I only needed 2 wires to each opener, so I cut off the remaining wires. I chose at random to use Blue and White. I chose to use Blue as the “common” and white for the other. No electricity is passing through these wires, it is simply providing “continuity”. That is, when the receiver gets an authorized signal, it essentially closes a switch that connects the two wires. The garage opener senses that the two wires have touched and opens or closes the door.
Receiver wiring
Closeup of receiver wiring

5. I stripped the ends of the wires and attached a short piece of cable from CH1 of the receiver to the Pushbutton and Common terminals on the first opener. I stapled the cable to the ceiling using curved staples for wires.
Closeup of opener wiring

6. I did the same steps to connect CH2 of the receiver to the common and pushbutton terminals of the second opener, this time using a 20ft piece of cable.
2nd unit wiring

That’s all there is to it. I tested each button on each remote and the doors opened and closed as expected.

I then erased the memory of the built-in receiver in both Linear units, and gave one of the new remotes to my wife, and took the older remotes, removed the batteries, and stored them in a box. Time will tell if this solution works well.

Fluorescence of stuff

Fluorescence is what happens when one frequency of light falls on a substance, and another frequency of light is returned. Sometimes a viewing filter is needed to exclude the light being used to illuminate the substance so only the fluorescent light can be seen.

After seeing a TV show about finding semen stains in hotel rooms using a blacklight, I started doing some reading about what kind of light works best. I found that in many cases a cheaper blue flashlight combined with an orange viewing filter (orange glasses) is the best combination for showing several fluorescent substances. This works best in a darkened room.

The idea here is that an orange filter will remove all light that isn’t orange (only lets orange through). So the blue light is excluded, except when it causes something to give off extra light (fluoresce). The effect is that you see a mostly very dark orange image, but then a bright greenish looking stain that really pops out.

The TV show only showed that some stains were visible, but there was no way to really identify WHAT the stuff was. In fact, here is a short list of things that will fluoresce under this lighting:

NOTE: Most fluids need to dry before they will fluoresce.

Soap (soap scum, droplets)
Soda pop
Cashews (actually several food residues)
Chewing gum residue
Semen/Vaginal fluid
Detergent residue (clothing soap often contains chemicals that make white cloth appear more white under light)
Some insect poisons (ant and roach powders)
Cleaners (like Mr Clean)
Sun screen (some kinds)
Tonic water or club soda (quinine)
Citrus juices
Rubber cement
Lots of dry powders, certain narcotics

It also will light up insects like scorpions, if you have those around. This is one way to find them in the dark.

From the list, it is clear that just because something glows doesn’t mean it is dirty or worse. Cleaners and soap glow brightly, so remnants of these can be on walls and objects. Conversely, just because it does NOT glow doesn’t mean it is clean from germs or possibly harmful chemicals.

Since I have two cats, and they vomit at least once a week, the blue flashlight and orange goggles are purrfect for finding spots that aren’t obvious. Just because the visible goop was removed doesn’t mean there isn’t a stain. Getting the remnant stains removed can be challenging since some cleaners leave a glowing residue. If the carpet has been cleaned and there are still glowing spots, you did your best. Let it go…

Here are views of soap, soap residue, and urine residue (using blue light and orange filter):


College students have been known to leave hidden messages or elaborate drawings on walls that are invisible under normal light, but show up brightly under black light (ultraviolet or UV).

Checking around a computer (rug, chair, keyboard, mouse, desk, etc) can show splashes of something otherwise invisible. Could be soda, I suppose…

Orange goggles
apx $7

Blue flashlight
apx $15

If you delve into forensics more, you will find that they have lights that can change color and other filters for viewing in order to better show certain kinds of substances. It is also a common statement that fluorescence only really helps detect stains, but doesn’t positively identify them as a particular substance (not everything that glows is semen, as is obvious once you look at the list above). Positive identification comes from chemical and DNA testing in a professional lab.

Here is one website that covers some of the various kinds of light and filters, and shows examples of results:

Garage Door quieting – 2nd method, much easier

After having installed a few vibration isolators on garage doors using my older complicated “hanger bolts” method, I wanted a much easier method. I removed the rubber vibration isolators from their housings and pushed them through the holes in a piece of angle iron (just like most garage door openers hang from already). I bought a couple of L-brackets from a hardware store and modified them slightly. I use these to attach to the opener motor housing.

NOTE: I’m not an engineer. If you choose to follow this design, it is at your own risk. I’m only showing how I approached the problem, not recommending that you do the same. If you are not comfortable lifting heavy objects and balancing on a ladder, cutting metal, and assembling things, please find a pro to do the install for you.

I go into more detail in the original posting linked above. See that one for more information. The basic concept is that rigid structures transmit vibration energy well, and this becomes noise in the rooms above the garage. Sometimes quite a loud noise. The goal in this project is to absorb the vibrational energy from the motor, and dissipate it through two pieces of flexible neoprene to keep it from continuing on into the wooden house beams.

I first measured the most critical piece of information: “How far down from the CEILING is the top of the motor housing?” This is also the where it will need to be when the project is complete. Varying a half-inch or so shouldn’t make any difference.

I placed a ladder with a built-in support beneath the garage door opener, detached the motor housing from the angle irons, and rested it on the ladder support. I attached the new piece of angle iron, isolators, and L-brackets to the housing and marked on the vertical pieces where it needed to be anchored.

I removed the vertical pieces and cut them, and then filed off the sharp edges, then remounted them but closer to center to fit between the rubber isolators.

Here is the result. Front view and back view.

This method took far less time and effort, requires only normal 3/4-inch 5/16 bolts and nuts, some angle iron, a couple of L-brackets, and the same vibration isolators removed from their housings.

The effect is the same, very quiet garage door opening. I didn’t even need to install the 45-degree angle iron that I removed from the original install.

Here is a list of the parts (not all pictured):
Mason 2LVR8 from Grainger.com $9 x2 ($18)
Machine bolts 5/16 x 2 1/2-in x2 [these hang through the rubber isolators]
5/16 metal washers x2
5/16 fender washers x2
3/8 (fit better) neoprene washers x2
5/16 nylon locking nuts x2
Angle iron 1 1/2 inch, 14ga, at least 1ft long
L-brackets x2 (size?)


angle iron

Same tools needed, but also a sawzall with a metal-cutting blade (or equivalent), and a file to take off the sharp edges and corners

Removing moss, algae, and lichens from the roof (asphalt shingles) and sidewalks

Like many in the Pacific Northwest, we had some moss on our roof and algae stains on our gutters. Also, the moss had embedded itself under a lot of the shingles and was pushing them up.

embedded moss

embedded moss 2

The algae and moss seep into the gutters, and if the gutters get clogged, the moss makes its way onto the deck and around the house perimeter.

The driveway and sidewalk around the house were very dark. This was a combination of years of dirt and dark algae growth due to continual wetness. The cracks between the driveway sections were filled with moss and dirt.

I read about various ways to handle this, and started first with a solution called “Wet & Forget” (benzalkonium chloride, aka BAC) that claims to remove algae and “crud” over a period of weeks or months following application. It did indeed work in some areas of the driveway, but other areas seemed to resist clearing.

So I began cleaning the driveway last year with a pressure washer. I’d read enough to know not to do this to our roof, since it would drastically reduce the life of the asphalt shingles. I cleaned the driveway (and completely clogged the driveway inset drain with the dirt and algae), and part of the sidewalk before stopping. That was last year.

This year, I began seeing the darkness of algae returning to the driveway, and I still had plenty of sidewalk and curb that were stained dark, not to mention the roof and rain gutters.

The benzalkonium chloride did clear some of the areas, but it starts to get a bit expensive given the amount of sidewalk and driveway I have. Pressure washing is faster, and I have the option to seal the concrete afterward. I bought 5 gallons of sealant for the driveway, but need to figure out how to do the washing without further clogging my driveway drain or flooding my garage.

I found a site dedicated to asphalt roofing and they had these two approaches:

1. A 50/50 water and bleach solution sprayed on with a hand sprayer. Let it set for 30 minutes and then wash off with a hose. This kills the algae and begins loosening the moss and algae. Bleach has the added benefit of removing stains.

2. A solution of benzalkonium chloride sprayed on with a hand sprayer. This one is just left on the roof, no washing should be done. It kills green algae and moss, and to some extent lichens, and then over the next 3-6 months of weather washes off the remains, leaving a nice clean and unstained roof.

Either method should be done when the temps are cool and there is little wind. Early morning is usually recommended.

There are pre-fab products containing benzalkonium chloride such as “Wet & Forget”, and some much higher concentrates in chemicals intended for clearing algae from pools. The latter is a far cheaper approach when mixing in a hand sprayer, though as always I’m not going to recommend you do this since it technically violates the labeling, even though it is the same chemical.

I started spraying the sidewalk and driveway in mid-August 2018. I sprayed a solution of benzalkonium chloride on my driveway, some rain gutters, and quite a bit of sidewalk that had dark algae staining. The weather has been hot and dry for quite some time, which is unusual but becoming more usual in the past few years.

The roof cleaner recommended a 25:1 ratio of water to 50% concentrate BAC. That is right around 10oz per 2 gallons water. I had been using 1oz or 1/10 the strength I should have been using.

9/8/18 I got up on the roof and sprayed the roof with the full strength mix and and ounce of liquid Moss Out.

10/14/18 No real sign of change in the roof or the sidewalk. Starting to think that bleach water is a better approach.

11/17/18 The moss actually died, but wasn’t obvious. Fresh green moss came out where I hadn’t sprayed. I sprayed some of it two days ago and it is clearly dying, so going to spray the rest with the mix.

05/02/19 It was clear that the spray and some later application of granules of Moss Out (zinc) had killed all the moss on the roof. The spray had also worked to clear the darkness from the sidewalk.

However, the embedded dead moss in the shingles of the roof still remained embedded. I went up on the roof with a knife and began the tedious task of cleaning out the moss and dirt with a knife. Since it was this way over nearly all of the roof (10+ years of accumulation), it took about 12 hours of careful balance work to clear it most of it out. Some of it I then swept off with a big broom, other I left for the wind and rain to clear. The roof looks a lot better now. Note: use an old screwdriver rather than a nice knife. The abrasive asphalt shingles turned my nice blade into a butter knife.
knife damage

To keep from getting near the edge on the 2nd story, I am using a 20ft extension pole with a piece of sturdy bent metal that hooks back toward me. I can sit near the peak and run the edge of the metal along the edge of the shingles to clear what I can see. I added a piece of scrap sheet metal to the pole to get at other edges that are more lateral to my location, but next to the edge of the roof. Falling from the 2nd story would be death or permanent damage, just not worth it.
moss tool

I still need to clean the outside of the gutters with some 409 and a bunch of towels.

Melted Doorbell

I honestly didn’t know that doorbells could melt. I had installed one at a worksite only to find out a few days later that it wasn’t working. I had wired it to a magnetic switch so that it would ring when someone opened the door, to notify the worker inside that someone else was there. Problem was that the power stayed on all the time the door was open, rather than sending a short burst of power. Sometimes the door was propped open for deliveries. Oops.

I ended up buying a timer circuit for it that powers-up, counts to 3, closes a power relay for about 1/3 second and then opens it again. The reason for the first delay is so that annoying people can’t stand at the door opening it and closing it to make the bell ring repeatedly. Yes, they do that sort of thing. Each one thinks it’s funny. The guy inside, not so much.

A picture of the melted mechanism shows the cheap plastic core for the right solenoid coils melted and froze the sliding pin in place.
melted doorbell

A picture of the programmable timer I used. I got this Uctronics gizmo off Amazon for about $12. It can be programmed for all kinds of functions. I already had a 12vdc source at the location, so this was a perfect match.


I have a home doorbell that currently only goes Ding, but no Dong. This may have happened to this one when a tweaker showed up early one morning and was mashing the doorbell button. I heard an odd DIINGggg…. and found him out there in a drug crazed state doing odd things. The police and ambulance came to take him away. But now my doorbell only goes Ding. He may have melted the other part by holding down the button. I haven’t bothered to look at it yet.