Headache

[esaj]

The spot-welder's waiting for more parts, as I found out through simulations that the stray/parasitic inductance in the cables can cause the voltage to spike above 100V and destroy the mosfet-switch bank with high currents. It will take a while, as I try to order components in bigger bulks to save on shipping, so I try to collect a larger list of stuff I need before ordering.

Now that I have wheel(s), I haven't spent much time on electronics, but I got some fever and haven't been able to ride today or yesterday. Today I thought I'd try my hand at creating a combined speedo/odo/tripmeter and battery voltage meter. The first prototype doesn't have its own step-down to power from the wheel batteries directly, but instead simply relies on "something" else giving it 5V supply voltage.

Nothing really special there. The 5V supply voltage comes from some outside source through a connector, and is put behind a (smallish, couple of hundred milliamps?) PTC-fuse, some bypass caps (for this prototype, I'll use just some MLCCs, I think I have those up to 47uF range) and a "jumper" (maybe I'll use a switch instead) to turn on and off the thing. An Arduino Nano will work as the brains of the device. Rest is just the 7-segment drivers (MAX7219's), bunch of connectors, pull-up for a hall-sensor to read the speed from tire rotation and a voltage divider for finding out battery voltage. Trip will be calculated based on speed, and total mileage will be intermittently saved into EEPROM, say every 200 meters for example, to save on the EEPROM write-cycles, and every time the wheel stops for longer than some amount of seconds (5 might be a good value). To save on the EEPROM wearout, it could also be interleaved by writing into consecutive addresses and at startup, reading through them and picking the largest value. Tire circumference will be hardcoded for prototyping.

I was thinking of using an OLED-display to show the values, but the ones I have are really small (about 1" from corner to opposite corner), so they'd be hard to read if showing many values (small characters), or it would have to alternate between different values, which would mean I'd have to stare down at it for longer when I want to see something specific. Instead, I decided to go with 7-segment leds, actually four of 4-character displays, driven by two MAX7219's. I did a similar setup last summer on a breadboard:

The working principle is pretty basic, measuring time passing between ticks got from a hall-sensor, and calculating the speed from there knowing the tire diameter and amount of magnets (how much distance it has traveled over time). I planned on using 6 magnets (I think I counted that the KS16 motor sideplate has 12 bolts, so it's easy to place them equally by placing one next to every second bolt). MAX7219's are pretty easy to use and each can handle up to 8 characters (so one 7219 for two 4-character displays). By using four displays, it's easy to show speed, trip and total mileage, plus battery voltage at the last one. For voltage measurement, I made a simple voltage divider with four 2.2k -resistors in series (to help with the power dissipation in each resistor) and 620ohm at the low-side of the divider, giving a ratio of   620 / (4 * 2200 + 620) = 0.0658174097664543524416135881104. For 67.2V (normal battery maximum), this will give 4,4229...V. I left some headroom vs 5V, as braking can momentarily push the voltage higher than battery maximum. At 5V reference, the LSB step of the 10-bit ADC will be around 4.88mV, which for now is enough precision (it's a little less than 75mV in the real battery voltage). It could be taken further with things like using more precise resistors, dropping the voltage lower and using a precision reference for the ADC, and/or using a separate 12- or 14-bit ADC chip, maybe I'll look into those in the future if it seems necessary. Likely the voltage's going to be jumping up and down a lot anyway, plus there's going to be all sorts of noise there anyway.

There's also a small capacitor (marked as 1n at least for now,) to smooth out sudden transients and a 5.1V zener to protect against overvoltage, but might have to lose the zener if it looks like it has too much influence on the readings (it has both capacitance and leakage). The impedance of the divider is relatively low (< 10K), as the cap has leakage, and apparently this can cause lots of error in the readings when using high impedance divider. Plus the MCU datasheets suggest using less than 10K input impedance for it anyway. It will draw about 6...8 milliamps, depending on the battery voltage, but considering how big the wheel batteries are, it's peanuts, especially compared to the mainboard and the motor draw. To prevent it from wasting charge when not in use, probably a switch should be added, but a better option would probably be using a logic level N-channel mosfet against the ground after the divider, that will be turned on only when the meter itself is powered. Assuming I ever get around to make a "better" version powered directly from the wheel, it will likely have an off-switch, or detect whether the mainboard's turned on, so it shouldn't discharge the batteries on it's own.

There's some extra connectors so I can easily add more devices using 5V and get access to the digital pins and the I2C-pins if need be. The 30k resistors for the current limiting of the 7219's are just a "rule of thumb" (should be around 20mA for red 7-segments), might need to tweak those around, if it seems that the segments are too bright (is that even possible? ) or if it draws so much current that it will eat away at it's own battery too fast.

I haven't cut the board yet, as it got pretty late before I had the layout down, I first tried with DIP-packaged MAX's, but ran out of space fast on a single-sided board, but fortunately I had some in SOP-24 (SMD)  -packages too. The MAX's could be chained together through the DOUT/DIN -pins, but the traces would have to jump through some hoops, and I had pins available, so I decided I'd control them separately from the MCU. Still had to add some 0-resistors to keep the ground-plane intact and a jumper (the via in the layout) to transfer +5V to the hall-sensor -connector. Trying to get the board milled during tomorrow... I can run the CNC while I work, so shouldn't be a problem, unless I can't get clean cuts at those SMD-chips. I set the feed rates so low that it shouldn't be a problem, but you never know

Edited May 29, 2017 by esaj

[Rehab1]

36 minutes ago, esaj said:

Now that I have wheel(s), I haven't spent much time on electronics, but I got some fever and haven't been able to ride today or yesterday. Today I thought I'd try my hand at creating a combined speedo/odo/tripmeter and battery voltage meter. 

Exciting! In my opinion your seedo/odo/tripmeter project should have it's own topic. It will be of interest to a lot of members!

[esaj]

Despite runny nose and (literal) headache, I managed to kick this forward.

Board after milling. Using slower feedrate, I could run it at a lot lower RPM, and there was no need for sanding at all. Of course the milling took a lot longer than usual. Some of the copper in the wider isolation has been left behind, should have used more overlap between the multiple passes, but this wasn't really a concern. It just helps with soldering, as getting a bridge somewhere is far less likely. Also I wanted to isolate the pins where the battery voltage is supposed to go, although it's not really large voltage (ie. there's no real concern of it striking over), I want to be pretty sure that I make no short circuits there on accident

Most of the SMDs in place. I actually found out that I have no 620-ohm resistors in the 1206 / 1% -book, but used a 5% later on... I'll fix it with software, although no idea what tempco those are  It's not like it's a "production" piece anyway. I used solder paste for the MAX7219's, the upper pads have the blobs in place. Maybe could have used a little less, it's pretty hard to dispense correctly by hand, usually it's like "too little...too little... too much!"   Sloppy solder work on some of the components too, I fixed it a bit afterwards.

All of the components and connectors in place, except for the PTC-fuse. I left it out for now, as I powered it with some hook clips anyway.

Testing that the displays and MAX7219's still work (ie. didn't mix up the pins or overheat them in soldering ), just running some sequential numbers through them. The wiring's a mess, but the 7-segments are meant to be soldered to their own board later on (I'll simply use dot matrix board for that, no need to mill an actual board for them) and connected with connectors where the pin-order can be set correct. Then just have to be careful not to insert the connectors upside down  Not that it likely would hurt, I don't think the 7-segments can get damaged with 5V even if the pins went wrong.

[esaj]

Oo, pretty colors. And a monumental waste of time. I probably used about 2.5 hours to make that  The thing is, the pins of the displays are so thin that they can easily lose contact with the female pinheaders on the boards. Nudge the display a little, and it's fine again, but if it's encased into something, that might be a bit harder to do. And making those wires with the headers is slooow...  Ever tried putting Dupont-headers on thin wires one by one without the special crimping tool for them?  

The easiest solution would be to make a board to which the displays are soldered directly. Probably should take that route instead  Actually, in hindsight, it would have probably been better to put the MAX's and the displays on their own board, with just data-input pins from another board. For a more "final" version, I think I go with the simple & cheap ready-made modules. A display like this (0.36" digits, like the smaller ones above, controlled by TM1637) costs about 70 cents:

It needs 2 pins (data + clock) from the MCU, plus VCC and GND, so 8 pins from the MCU, but it's not like I'm short on pins... The best option would probably be make a 2-sided board in a fabhouse and put the ATMega328P & peripheral components directly there without a separate Arduino-board, and then put the 7-segments directly onto the board, so it's just one solid piece, with no other wiring than the battery lines and the hall-sensor.

 

Edited May 31, 2017 by esaj

[Rehab1]

24 minutes ago, esaj said:

Oo, pretty colors. And a monumental waste of time. I probably used about 2.5 hours to make that  The thing is, the pins of the displays are so thin that they can easily lose contact with the female pinheaders on the boards. 

God that takes patience! Excellent job but  tedious work!  

[Carlos E Rodriguez]

3 hours ago, Rehab1 said:

God that takes patience! Excellent job but  tedious work!  

Maybe I a lazy but I would rather have used some of these. Would it have been easier?

Only  about $3.00 for the whole thing. 

[Carlos E Rodriguez]

10 minutes ago, Carlos E Rodriguez said:

Maybe I a lazy but I would rather have used some of these. Would it have been easier?

Only  about $3.00 for the whole thing. 

And then add one of these

 

[esaj]

5 hours ago, Carlos E Rodriguez said:

Maybe I a lazy but I would rather have used some of these. Would it have been easier?

Only  about $3.00 for the whole thing. 

 

5 hours ago, Carlos E Rodriguez said:

And then add one of these

 

The board the Arduino sits on currently is made to measure to a certain type of enclosing I have, but yeah, that would work too, if you use OLED, or use separate modules which already carry the 7-segment controllers. You'd still need a separate board for the battery voltage input, as the voltage must be divided far down, at or below 5V at assumed maximum voltage the wheel can make while braking, I've gone with 75V, which I think is conservative enough, but there's also a 5.1V zener to handle any overvoltage to prevent damage on the board (I haven't checked if the ADC inputs have their own internal protection diodes, could be).

I thought about using a similar OLED like that (I probably have a bagful of those somewhere in the drawers ), but then thought it would be too small:

"I was thinking of using an OLED-display to show the values, but the ones I have are really small (about 1" from corner to opposite corner), so they'd be hard to read if showing many values (small characters), or it would have to alternate between different values, which would mean I'd have to stare down at it for longer when I want to see something specific. Instead, I decided to go with 7-segment leds"

Those OLED displays might be nice for something that fits inside the helmet, and connects to the wheel directly over Bluetooth (I have some NodeMCU's / ESP8266's that have WLAN and BT on the same board, but not sure if they support BT LE) to show mainboard data. The problem, as usual, is powering things, I don't think I'd want 18650's right next to my face   Maybe running a wire from cells in pocket or something...

 

Edited May 31, 2017 by esaj

[Carlos E Rodriguez]

4 hours ago, esaj said:

 

The board the Arduino sits on currently is made to measure to a certain type of enclosing I have, but yeah, that would work too, if you use OLED, or use separate modules which already carry the 7-segment controllers. You'd still need a separate board for the battery voltage input, as the voltage must be divided far down, at or below 5V at assumed maximum voltage the wheel can make while braking, I've gone with 75V, which I think is conservative enough, but there's also a 5.1V zener to handle any overvoltage to prevent damage on the board (I haven't checked if the ADC inputs have their own internal protection diodes, could be).

I thought about using a similar OLED like that (I probably have a bagful of those somewhere in the drawers ), but then thought it would be too small:

"I was thinking of using an OLED-display to show the values, but the ones I have are really small (about 1" from corner to opposite corner), so they'd be hard to read if showing many values (small characters), or it would have to alternate between different values, which would mean I'd have to stare down at it for longer when I want to see something specific. Instead, I decided to go with 7-segment leds"

Those OLED displays might be nice for something that fits inside the helmet, and connects to the wheel directly over Bluetooth (I have some NodeMCU's / ESP8266's that have WLAN and BT on the same board, but not sure if they support BT LE) to show mainboard data. The problem, as usual, is powering things, I don't think I'd want 18650's right next to my face   Maybe running a wire from cells in pocket or something...

 

I hear you. Don't want a hole in your head from an exploding battery. Lol. 

It be cool. If helmets would be designed with a cell phone battery  build  onto the design

so you have some NodeMCU! That is cool. Have you tried them? Do you program with Node-Red or something else?

Edited May 31, 2017 by Carlos E Rodriguez

[esaj]

2 hours ago, Carlos E Rodriguez said:

I hear you. Don't want a hole in your head from an exploding battery. Lol. 

It be cool. If helmets would be designed with a cell phone battery  build  onto the design

so you have some NodeMCU! That is cool. Have you tried them? Do you program with Node-Red or something else?

Actually, no, I haven't tried them much, just testing some that they work in general, been on my todo-list for quite some time though  Luckily they can be programmed with C/C++, haven't tried with Lua. So far, I haven't even had a project where I'd need anything faster or with more memory than ATMega328  Mostly I work with either the basic Arduino IDE ( + https://github.com/esp8266/Arduino for ESP8266's) or Atom + PlatformIO ( http://docs.platformio.org/en/latest/ide/atom.html ). Depending on "need for speed", I either go with basic Arduino-libraries or just screw around directly with the actual ATMega registers... The latter's more error-prone, but for example the ability to write whole port states (up to 8 pins) in one go makes quite a difference in speed, especially if you look at what something like Arduinos digitalWrite() or such does behind the scenes, no wonder it's slow in comparison. Tried a bit with Atmel Studio too, but it seemed like shooting mice with nuclear bombs for simple projects. I'm not sure if my inventory is up-to-date anymore, but according to it, the current MCUs I have are

Microcontrollers
Boards
Name	Amount	Notes
Arduino Mini Pro	7	32u4-chip, USB HID
Arduino Uno	4
Arduino Nano	10	MiniUSB, some might have 168-chip
Arduino Nano	5	MicroUSB, 328P all
Arduino Pro Micro	6	No USB
Arduino Lilypad	2
Arduino Mega2560	4
Arduino Uno	4
AtTiny85	3	Small breakout with MicroUSB
Wemos D1 Mini	1	ESP8266
Wemos D1	3	ESP8266
Chips
ATTiny85	5	DIP
ATTiny2313A	1	DIP
ATMega328P-PU	4	DIP
Programmers
AVR ISP	2

 

So nothing really fast or complex, like ARMs, at least so far.

In general, I try to keep an inventory of the stuff I have, so I have a handy and fast reference when designing stuff to see what I have available, but it's often out-of-date when it comes to amounts:

In practice, my study has turned into a junkyard  I moved stuff around about a month back and got some more useable desk space, but it has already been swallowed by all sorts of junk... time to clean up again

While the cabinets with the small boxes are labeled correctly etc, there's a lot of stuff that's just stuck into the drawers beneath the desk:

Which leads to "funny" situations, like "where did I stuck those XYZ's..?"   In addition to all the Aliexpress-stuff I've accumulated, I also keep a separate stock of components ordered from actual distributors (mostly TME & Mouser) under the corner table with the CNC, plus a stock of stepper- and servomotors:

It's organized... sort of.  The big bags have labels like "Zeners", "ICs", "Resistors & PTCs"... then I just have to turn it upside down to find what I'm actually looking for The red bags in the shelf are 1206 resistors and SMD MLCC's ordered by value, so at least there's some method to the madness. But mostly I use a small sample books for SMD-resistors, capacitors and transistors that's always handy when soldering, and only fill it up when needed.

Despite relatively large collection of "mostly needed" stuff, I still keep running into situations where I don't have a part that would fit the need better (like for example SMD PTCs that are rated up to or above 75V for safety in the battery voltage measurement, or 7-segment drivers with a pinout that would make it possible to wire the displays in one layer on the same board without jumpers), so often I end up working around the issue with what I happen to have... Definitely not the best way to go, but it sort of works in general 

 

Edited May 31, 2017 by esaj

[Carlos E Rodriguez]

so you do this just for fun or you develop for clients? or employer?

 

[esaj]

33 minutes ago, Carlos E Rodriguez said:

so you do this just for fun or you develop for clients? or employer?

Just for fun and learning... the stuff I do is mostly pretty simple & basic, most of it is documented in this thread. I wouldn't trust my understanding of electronics to be good enough to design a real "commercial" device from scratch, especially if mains AC or high voltages are in play. And no real client would accept a board milled with a shoddy tabletop-CNC and filled with components from Aliexpress, enclosed in a cheap plastic box  Complex analog-circuitry and RF-design is still mostly just black magic to me.

I work as a programmer for living, but not in embedded development.

Edited May 31, 2017 by esaj

[Carlos E Rodriguez]

9 minutes ago, esaj said:

Just for fun and learning... the stuff I do is mostly pretty simple & basic, most of it is documented in this thread. I wouldn't trust my understanding of electronics to be good enough to design a real "commercial" device from scratch, especially if mains AC or high voltages are in play. And no real client would accept a board milled with a shoddy tabletop-CNC and filled with components from Aliexpress, enclosed in a cheap plastic box  Complex analog-circuitry and RF-design is still mostly just black magic to me.

I work as a programmer for living, but not in embedded development.

You are better than many I know. cool!

[Hunka Hunka Burning Love]

Maybe a couple of these might help!

http://www.ikea.com/ie/en/products/desks/desk-computer-desks/fredde-workstation-black-art-50219044/

Or maybe this... 

BTW I can spot a hidden Van Gogh "The Starry Night."  

Edited May 31, 2017 by Hunka Hunka Burning Love

[esaj]

1 hour ago, Hunka Hunka Burning Love said:

Maybe a couple of these might help!

http://www.ikea.com/ie/en/products/desks/desk-computer-desks/fredde-workstation-black-art-50219044/

Not a bad idea, I've actually talked about building a desk/shelf-thingamabob from wood with garage-elf (for those who don't know, ie. haven't been in Discord that much: Garage-elf is a friend of mine who uses my garage to build synthesizer casings)... Something like this maybe?

Of course it has to be "self-standing", I don't want to bolt them directly to outer walls and break the vapor barriers. 

 

 

1 hour ago, Hunka Hunka Burning Love said:

BTW I can spot a hidden Van Gogh "The Starry Night."  

That's actually a jigsaw puzzle... almost all of our "paintings" hanging in the walls are framed jigsaw puzzles

[Hunka Hunka Burning Love]

17 minutes ago, esaj said:

That's actually a jigsaw puzzle... almost all of our "paintings" hanging in the walls are framed jigsaw puzzles

I've seen some of those really large puzzles, but I don't think I'd have the patience to complete one!  Did you hear about what happened to this guy?

I don't think I could make any furniture that would be worthy of having inside a house.    The amount of time to put together one from scratch versus a prefab that you screw a few pieces together?  I'd stick with the Ikea stuff.  Fitting a desk into small Mazda might be tricky though...

[esaj]

On 6/1/2017 at 0:52 AM, Hunka Hunka Burning Love said:

The amount of time to put together one from scratch versus a prefab that you screw a few pieces together?  I'd stick with the Ikea stuff.  Fitting a desk into small Mazda might be tricky though...

I call your Ikea-furniture and raise you a hand-made shelf with rack-mount:

I've been a busy little bee lately, although everything's still not finished, plus I've had to put all other projects on hold... The lights are controlled from the rack-mounted front panel, which also sports some short-circuit protected outputs from the ATX driving the lights:

One of the 12V outputs is short-circuited through a patch-cable, just for show. All the stuff behind that panel is built from left-over scrap through-hole parts I had onto matrix-boards, couldn't be arsed to design actual boards  

I recognize the irony that I use ad-hoc designed boards and scrap parts, when I usually spend days doing prototypes on designed & CNC-milled boards from pristine components... Especially since this is supposed to be semi-permanent, whereas many of the prototypes get scrapped soon afterwards.  

There's a couple of extra holes for stuff I was planning to do later. I had trouble fitting the old large light fixture on the desk, so instead I took apart an old desklight (for the swiveling frame), and bolted a couple of 10W power leds onto a aluminum flat:

I had to add some heatsinks as those things heat up a lot   The measurement side on the left (seen in the first picture) has a piece of board with two led-tapes & 3 x 3W power leds. Soo much easier now that I actually see what I'm doing   The lights are driven by constant current sinks, using power mosfets and op-amps, and the current can be adjusted with the knobs on the front panel and turned off with the buttons.

Still long ways to go, I've got to move the CNC, clean up a lot of stuff, get my new hot-air station that arrived today set up etc, but it's getting there.

 

 

Edited June 27, 2017 by esaj

[Hunka Hunka Burning Love]

Not bad not bad at all!  You ARE handy!    

So what hot air rework station did you end up getting?  Ultra-cheap Chinese electroshockmebbemebbenot (I'm practicing my Germansprechen) model or something higher end?

Edited June 27, 2017 by Hunka Hunka Burning Love

[Rehab1]

Great job! I see your rack has slide rail attachments for mounting equipment. My cases  have symmetrically spaced holes along the rails. The exact dimensions are based on some world standard for rack cases. I like your case's rail setup. Much easier to align all of the components before the final tightening of the screws.

[esaj]

35 minutes ago, Hunka Hunka Burning Love said:

Not bad not bad at all!  You ARE handy!    

Thanks, but in reality I had lots of help from the Garage Elf, he for example sawed small slivers at both sides in of the ends of the side plywood boards, so that the side boards slide inside rack rail profiles, and were then fastened with three M6 bolts and "strike-nuts" (don't know if that's the correct English term, the kind of nuts that you drill a hole for and then hammer inside the board so the teeth hold it in place):

It's really sturdy, the 10kg (22lbs) power supply unit is held only by the four bolts on the front and nothing budges in the least bit. I think the desk will give in before the rails or the cabinet  Luckily it has a sideways support underneath, otherwise the table top would probably already start to bend from all the weight...

 

Quote

So what hot air rework station did you end up getting?  Ultra-cheap Chinese electroshockmebbemebbenot (I'm practicing my Germansprechen) model or something higher end?

Not the cheapest of the cheap, but nothing really high-end either: an Ayoue.. .Aoyue... "vowels" INT968+. The few people who have those said that they've worked just fine and should be enough for hobbyist use:  http://www.aoyue.eu/aoyue-int968a-repairing-station-hot-air-soldering-station-3in1-with-tweezer.html 

I haven't even opened the box yet  (and keep reminding myself that when I do, I have to remove a screw on the bottom that's there for transportation, but must be taken off before use). Also ordered some extras, like a pick-and-place vacuum-piece that replaces the fume-extractor (already got a fume-extractor, plus I have a 100CFM = 160m³/h SystemAir industrial fan duct-blower in storage, if I can mount it and need more suction ) and the tweezers (the link says comes with tweezers, but not these): 

Should be handy for removing SMD-resistors and such, but might also be total crap

 

29 minutes ago, Rehab1 said:

Great job! I see your rack has slide rail attachments for mounting equipment. My cases  have symmetrically spaced holes along the rails. The exact dimensions are based on some world standard for rack cases. I like your case's rail setup. Much easier to align all of the components before the final tightening of the screws.

Yeah, actually I think the pre-drilled holes might be better (at least when using standard-sized equipment, ie U/unit-heights), but I got the rail for free and this was a good opportunity to put it into use. Like I mentioned in the "ever buy stuff..." -thread, right after the cabinet was built, another friend offered me his 12U floor-rack (the wheels can be removed to use it on a table or such) for one beer, so it's currently sitting in pieces the guest room (along with all the parts cabinets and random this and that) waiting for me to get around to figure where I put it.

 

Edited June 27, 2017 by esaj

[The Fat Unicyclist]

Very nice... But I may prefer the racks at Tilted Kilt. 

@Hunka Hunka Burning Love - what do you think? 

[Keith]

On 31/05/2017 at 10:52 PM, Hunka Hunka Burning Love said:

I don't think I could make any furniture that would be worthy of having inside a house.    The amount of time to put together one from scratch versus a prefab that you screw a few pieces together?

Try cutting hundreds of teeth out of plywood with a scroll saw. I got bored over Christmas and went in the completely opposite direction to @esaj - built a clock that is straight out of the 17th century. It took me nearly two months to get it working correctly. BTW, the drive weight is 13lb (6.5Kg) and it drops, by complete accident 1 inch per hour so runs for 57 hours. I made everything except the bell and the carbon pendulum rod, old bent model helicopter mainshafts came in handy for the arbors.

 

Edited June 27, 2017 by Keith

[Hunka Hunka Burning Love]

Wow that's pretty cool and VERY impressive!  It's good to see true artisanry still exists.  Makes my Ikea clock at $2.99 seem kinda pedestrian.  

[Hunka Hunka Burning Love]

22 hours ago, The Fat Unicyclist said:

Very nice... But I may prefer the racks at Tilted Kilt. 

@Hunka Hunka Burning Love - what do you think? 

Both are perfectly acceptable!    I don't discriminate!

So are you getting excited for your upcoming visit?  Hopefully it will be a good turn-out with temperate weather.

Edited June 28, 2017 by Hunka Hunka Burning Love

[The Fat Unicyclist]

1 hour ago, Hunka Hunka Burning Love said:

So are you getting excited for your upcoming visit?  Hopefully it will be a good turn-out with temperate weather.

Yes, excited and nervous - not only will I be riding in a new environment, but it will be on unfamiliar (and borrowed) wheels!

And I just found out that there's a heatwave going on... And I find riding with a parasol so much harder!