Servobay DWG SB-01 · REV C

SHEET 00 General arrangement

Plan a robot arm’s moves, right in your browser.

For students, hobbyists and robot builders: drag a virtual arm to a point, see how quickly it can get there without jerking, tune its motor, and save a tamper-proof record of the run.

Under the hood: exact joint-angle maths (inverse kinematics), jerk-limited motion profiles, a motor-control simulation (PID), and run records fingerprinted with SHA-256 that you can sign with a Solana wallet. Free, nothing to install.

Move the robot arm How it works
Solver
closed-form IK
Profile
7-segment S-curve
Loop
PID, 1 ms step
Seal
SHA-256 + Ed25519
PART 2R planar arm θ1 0.0° θ2 0.0° TARGET — SCALE 1:4

HOWHow it works in 3 steps

  1. 1You drag

    Drag the robot arm’s hand to where you want it.

  2. 2The page works it out

    Joint angles, a smooth path and motor settings, calculated instantly.

  3. 3You get

    Clear charts and a run record you can save or sign.

Nothing is moved or charged. The only thing that ever touches the blockchain is an optional note you choose to sign yourself.

REFReference clock Solana mainnet

What this does: shows the live Solana network clock that your saved records are time-stamped with. A slot is one tick of that clock; a blockhash is the unguessable code stamped on it.

Slot—getSlot
Mean slot time—ms · last 10 min
Slot jitter (σ)—ms · per 60 s sample
Throughput—tx / s
Slot period, last 10 samples
01

Move the robot arm

What this does: you point to a spot and it tells you exactly how far to bend the shoulder and elbow to reach it.

Drag the orange target. The solver (inverse kinematics) returns both joint angles, checks the joints’ limits, and warns when the arm is stretched straight, where it is hard to control.

Drag target · arrow keys nudge · click empty space to add a waypoint
Geometry
Target x, y—
θ1 shoulder—
θ2 elbow—
Reach used—
Manipulability—
Status—
Waypoints 0
    02

    Plan a smooth move

    What this does: works out the fastest way to turn a joint without sudden jolts that wear out motors.

    Give it how far to turn and the speed, acceleration and “jerk” (how suddenly acceleration may change) limits. It returns each phase of the move and the full motion plot.

    Move
    PhaseJerkDuration
    Plan a move to see the phases.

    Position deg
    Velocity deg/s
    Acceleration deg/s²
    Jerk deg/s³
    03

    Tune the motor

    What this does: shows how a joint motor reacts when told to move, so you can pick settings that are quick but don’t overshoot.

    A simulation of one joint motor (a “PID” controller: Kp pushes, Ki removes leftover error, Kd damps wobble). Move the sliders and the response chart redraws instantly.

    SetpointJoint angleTorque command±2 % band
    Gains simulation
    Plant
    Rise time 10–90 %—
    Overshoot—
    Settling (2 %)—
    Steady-state error—
    ITAE—
    Peak torque—

    SHEET 07 Exploded assembly

    What a run is made of

    1. Base and shoulder servo. The fixed frame. θ1 is measured from here.
    2. Link 1 and elbow servo. L1 sets the inner reach; the elbow carries θ2.
    3. Link 2 and tool point. The tool point is what the IK solver places on the target.
    4. Profile and loop. The S-curve feeds setpoints; the PID turns them into torque.
    5. Receipt. Every parameter above is hashed, signed and, if you choose, stamped on mainnet.
    A · BASE / SHOULDER SERVO B · LINK 1 + ELBOW L1 C · LINK 2 + TOOL L2 D · S-CURVE + PID E · RECEIPT (SHA-256)
    04

    Save a tamper-proof record

    What this does: saves every setting from this run with a fingerprint, so anyone can later check nothing was changed.

    Your arm, move and motor settings are bundled, time-stamped with a live Solana blockhash and fingerprinted with SHA-256. You can add a wallet signature, and optionally write the fingerprint on chain as a memo.

    SHA-256Seal a receipt to compute its hash. 
    
      
      
    
    
    
    
      
    Verify a receipt
    
      
    Paste any Servobay receipt JSON. The hash is recomputed here, the signature checked with Ed25519 and the anchor slot looked up on mainnet.
    
      
      
      
      
    
      
  
      

      






      
  
      
    05
    
      Find saved records
      What this does: looks up any Solana wallet and lists the notes (memos) it wrote on chain, including Servobay records.
      Paste a wallet address (its public account number). We read its latest 100 transactions and show every memo with its time.
      
  
      
  
      
    
    
  
      
  
  
      
  
      
    
      
      
      TimeMemoSlotStatusTx
      
      
      No address read yet.
      
    
      
  
      
  

      



      
  
      06How a bench run works
      
  
        
    
      1. Place
        Put the tool point where you need it. The closed-form solver picks the elbow branch you asked for and refuses targets that break a joint limit.
        2. 
    
      2. Profile
        The planner limits jerk, so acceleration ramps instead of stepping. Gearboxes and payloads see smooth torque, and the plot shows each phase.
        3. 
    
      3. Tune
        The joint loop is simulated at 1 ms. You read rise, overshoot and settling straight off the plot, or let the ITAE search pick gains for you.
        4. 
    
      4. Seal
        All of it becomes sorted JSON, hashed with SHA-256 and anchored to a live slot. Sign it with your wallet; stamp the hash in a memo if you want a public timestamp.
        5. 
  
      

      



      
  
      07Bill of materials: what is live, what is a model
      
  
      
    
      
      
      ItemKindSource
      
      
        
      IK solver, reach envelope, manipulabilityreal mathsClosed-form two-link solution, in your browser
      
        
      S-curve plannerreal mathsExact piecewise integration of a jerk profile
      
        
      PID step responsesimulationSecond-order joint model, 1 ms semi-implicit Euler
      
        
      Reference clockliveSolana mainnet: getSlot, getRecentPerformanceSamples
      
        
      Receipt anchorlivegetLatestBlockhash, getBlockTime on mainnet
      
        
      Receipt hash and signaturecryptoWebCrypto SHA-256 and Ed25519
      
        
      Run loglivegetSignaturesForAddress memo field, mainnet
      
            
    
      
  
      

      



      
  
      08Questions
      
  
      
    
      What is this, in one sentence?
      A free practice bench where you can move a virtual robot arm, plan smooth motions, tune its motor and save a checkable record of the result.
      
    
      Is it safe? Does it touch my money?
      Yes, it is safe, and no, it does not touch your money. Connecting a wallet only shares your public address. Signing a record costs nothing. The only optional blockchain action is writing a short public note, which costs a network fee of about 0.000005 SOL and only happens if you approve it in your own wallet. No coins are ever sent anywhere.
      
    
      What do the technical words mean?
      Inverse kinematics (IK)
      Working out joint angles from where you want the hand to be.
      Jerk
      How suddenly acceleration changes. Less jerk means smoother, gentler motion.
      PID
      A common motor controller with three knobs: push, catch up, and calm down.
      Slot / blockhash
      A tick of the Solana clock and its unguessable code, used as a time stamp.
      SHA-256
      A fingerprint for text. Any change gives a different fingerprint.
      Signature
      Your wallet’s free proof that you approved a piece of text.
      Memo
      A short public note written into a Solana transaction.
      Wallet address
      Your public Solana account number. Safe to share.
      
    
      Is this connected to a real robot?
      No. Servobay is a planning and tuning bench. The IK and S-curve maths are exact and you can copy the numbers into a controller, but the PID plot is a simulation of a simple joint model, not a measurement.
      
    
      What does connecting my wallet do?
      It shares your public address. Servobay uses it to prefill the run log, show your SOL balance for the stamp fee, and sign receipts. Signing a message costs nothing and sends nothing.
      
    
      What exactly is stamped on chain?
      Only a short memo, servobay:v1: plus the first 32 hex characters of the receipt hash and the run label. It goes through the SPL Memo program. No SOL or tokens move, apart from the normal network fee.
      
    
      Why anchor to a blockhash?
      A recent blockhash cannot be known in advance, so a receipt that contains one was made after that slot. The verifier looks up the slot's time on mainnet to show when that was.
      
    
      Where is my data kept?
      In this tab, and in your browser's local storage for the receipt draft. Nothing is uploaded. The only network calls are read-only mainnet RPC requests through this site's proxy.
      
    
      Does Servobay hold funds or have a token sale?
      No. The site never holds funds, never asks for a seed phrase and has no audits, partners or users to claim. It is an independent concept.