DIY Pedal Box (low cost?!?! probably...)

Hi.
TLDR:
I made a Pedal Box using Aliexpress Hand Brake. V1 was hydraulic and now, V2 is Load Cell based. (now go watch the pictures :D )

PB_V2-01.jpg


TL Did R:
Around 2017 I decided to make my own Pedal Box. Because I like the challenge of building good quality stuff on a budget, I was searching the best alternative for a DIY Pedal Box.
Started looking for the OBP pedal box, but 2 problems came up: first, was the price, not budget friendly; Second, I was going for the hydraulic root and wanted to reduce the chances of oil leaks. A complete pedal box comes with 2 brake master cylinders and I didn’t want to manage 3 master cylinders (the clutch was going to be hydraulic too)... Because of that, I went in the direction of an individual 3 pedal set. One accelerator, one brake and one clutch. With the advantage I could play with the position of the pedals separately.
OBP offers the individual pedal set. But buying 3 would be too expensive… (today, around £410+shipping)

OBP_PEDAL.JPG

Then I had the idea of using a Hand brake. Since the handbrake uses the same master cylinder system as the brake pedal. I went online looking for the cheap/stable handbrake money could buy. I found the best option was this:

Aliexpress_Handbrake.jpg

NOTE: The price is always changing in Aliexpress.
When I wrote this text, this was the price with shipping to Europe: +-30€x3 = 90€ (more less the same I paid 5 years ago). Sometimes it is more expensive…

And it is easy to modify and convert to Accelerator/Brake/Clutch pedal. Just cut the top of the handle, drill a hole and attach a pedal face. (I bought OMP pedal face)

IMG_20200423_174304.jpgomp-long-pedal-set.jpg

More pics from the Version 1.0 here:


I used them for almost 2 years without any problems and was really happy with them. But after the birth of my second child, I had to put the sim racing aside. So, the pedals and rig went to the basement.


Version 2.0

Fast forward some years, my kids are big enough, so I can focus some energy on sim racing again. It was time to rebuild the pedals. But everything went downhill this time… After disassembling all the pedals and hydraulic fitting to clean everything, I wasn't able to avoid oil leaks. The rubber of the master and/or slave cylinder couldn’t seal any more. Then I had leaks in the fittings… There was oil everywhere. My wife wasn’t happy. I wasn’t happy… I said F this… I will go the Load Cell way.
Having a 3d printer now, I was able to design something better than the last time (I used a kitchen cutting board for the plates that hold the springs and hand saw them).

So, after some prototypes, I am finally happy enough with my last iteration of the pedals and would like to share them.

PB_V2-1.JPG

Onshape 3d model link:
Google photos Album link:

Declaimer: This is not a "How to do it". Just an example of what can be made. Most of the solutions and decisions were made because of the available hardware I accumulated along the time, like springs and bolts, magnets, etc.
 
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Accelerator/Clutch
IMG_20220225_142553.jpg

For this combo, I’m using Hall Effect Sensors (HES), to read the pedal Rotation.

My latest solution is a copy from someone idea, somewhere on the internet. Put the HES (1) between 2 magnets (2). This solution gives me more range in comparison with a single magnet facing the HES. Unfortunately, this solution doesn't use the total range of the controller, just around 50%...

PB_V2-3.JPG


Another problem is the kinematic of the pedal. If you notice, after the total rotation, the “Sliding Rod” (1) is rigidly attached to the “Spring Plate” (2), and doesn’t make a linear movement. There are some degrees of rotation (3). As A consequence of that, the lower spring will be compressed more than the upper one. And the magnets will slide around the HES at different heights. So far I have not noticed any big disadvantages, therefore will keep it this way.
Note: after some testing, the most comfortable pedal rotation degree, for my driving position, is 18 deg or less (GT Style).

PB_V2-4.JPG


IMG_20220225_144002.jpgIMG_20220225_144006.jpg
 
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Brake Pedal
IMG_20220225_122801.jpg

For the Brake I replaced the Hydraulic system for a S-Shape Load Cell.
Once, I saw someone using a S-Shape for a Brake Pedal (saw it many years ago in Simracing expo a pedal box from an italian company, if I’m not wrong).
I was intrigued with the idea since then and decided to test it. I ordered a 200Kg Load Cell from Aliexpress.
I had some small challenges to fit it in the pedal. The fixing holes from the Load Cell are M12 threaded. And the fixing point of the pedal lever can only fit a M8 Rod End. So, I have a thread adapter M12 to M8.
For the rear side of the pedal, I bought a steel U Profile and cutted to fit. But, this was a mistake. Today, I would buy a simple flat bar 4/5mm thickness.

IMG_20220225_122825.jpgIMG_20220225_122815.jpg
IMG_20220225_122258.jpg

Electronic

I have been using, all these years, a Leo Bodnar Load Cell board. But after starting using this new Load Cell, I started to have some adjustment problems. I wasn’t getting a linear pressure curve out of them. And unfortunately Leo Bodnar doesn’t offer a good solution to manage this problem. I was getting something like a Square root curve. 20% pressure input on the pedal, would put me almost at 40%. I wasn’t happy with it…
But I saw some nice alternatives to the Leo Bodnar board, that offers the possibility to change the shape of the curve. Using a Bluepill STM32F103C8 board and Freejoy software.
So I bought some boards. And some load cell amplifiers (INA122). I Did some tests and a new hope arose!!!
I cannot express how happy I am with this stuff and the software!
The final control board:
IMG_20220225_152113.jpg

The end.
 
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Brake Pedal
View attachment 547788
For the Brake I replaced the Hydraulic system for a S-Shape Load Cell.
Once, I saw someone using a S-Shape for a Brake Pedal (saw it many years ago in Simracing expo a pedal box from an italian company, if I’m not wrong).
I was intrigued with the idea since then and decided to test it. I ordered a 200Kg Load Cell from Aliexpress.
I had some small challenges to fit it in the pedal. The fixing holes from the Load Cell are M12 threaded. And the fixing point of the pedal lever can only fit a M8 Rod End. So, I have a thread adapter M12 to M8.
For the rear side of the pedal, I bought a steel U Profile and cutted to fit. But, this was a mistake. Today, I would buy a simple flat bar 4/5mm thickness.

View attachment 547785View attachment 547787
View attachment 547786

Electronic

I have been using, all these years, a Leo Bodnar Load Cell board. But after starting using this new Load Cell, I started to have some adjustment problems. I wasn’t getting a linear pressure curve out of them. And unfortunately Leo Bodnar doesn’t offer a good solution to manage this problem. I was getting something like a Square root curve. 20% pressure input on the pedal, would put me almost at 40%. I wasn’t happy with it…
But I saw some nice alternatives to the Leo Bodnar board, that offers the possibility to change the shape of the curve. Using a Bluepill STM32F103C8 board and Freejoy software.
So I bought some boards. And some load cell amplifiers (INA122). I Did some tests and a new hope arose!!!
I cannot express how happy I am with this stuff and the software!
The final control board:
View attachment 547789

The end.

Great work :)
I was looking at doing the same thing but am concerned about the stability and quality of the lever pivot ?
 
Great work :)
I was looking at doing the same thing but am concerned about the stability and quality of the lever pivot ?

They work really well and I'm very happy with them. But it isn't perfect. I wouldn't buy this pedals from a company. But because they were made by me and I know the limitations, I'm OK with them.
The Arm doesn't have ball bearing or a quality bushing (Bottom rotation axis). So, they have some play. But while driving you cannot notice. If you tighten well, you will have less play, but you will have more drag and will not rotate so well.

If you have a tight budget and you like to DIY, then, I think it is a good option. Other then that, I think this is more a creative challenge.
Today, I would go in different direction (and i have already a new concept).
 
They work really well and I'm very happy with them. But it isn't perfect. I wouldn't buy this pedals from a company. But because they were made by me and I know the limitations, I'm OK with them.
The Arm doesn't have ball bearing or a quality bushing (Bottom rotation axis). So, they have some play. But while driving you cannot notice. If you tighten well, you will have less play, but you will have more drag and will not rotate so well.

If you have a tight budget and you like to DIY, then, I think it is a good option. Other then that, I think this is more a creative challenge.
Today, I would go in different direction (and i have already a new concept).
thanks :)
i already have a similar handbrake for my brake using a G29 pedal but was looking to do more diy and have all 3 pedals using them
see here : https://www.xsimulator.net/communit...ulic-load-cell-brake.14909/page-3#post-241842
these might be a cheaper option but then again might end up costing almost as much and cost a lot of time and hassle to end up with something not as good as a manufactured pedal set.
also considering using heusinkveld copies and just adding my hydraulic loadcell to the brake. probably my best option actually.
 
thanks :)
i already have a similar handbrake for my brake using a G29 pedal but was looking to do more diy and have all 3 pedals using them
see here : https://www.xsimulator.net/communit...ulic-load-cell-brake.14909/page-3#post-241842
these might be a cheaper option but then again might end up costing almost as much and cost a lot of time and hassle to end up with something not as good as a manufactured pedal set.
also considering using heusinkveld copies and just adding my hydraulic loadcell to the brake. probably my best option actually.
So you are aware about the quality! :D
I would go in the direction you are talking. If you have access to a company like "Send Cut Send". You can mod the DIY Open Source pedals you find in the internet, to use a Hydraulic Master Cylinder.
Good Luck, and share your creation!
 
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