Home › Classroom Wheels › Substitute Teacher PickerPrepared roster tool Substitute Teacher Name Picker Substitute Teacher Name Picker helps a visiting teacher choose students for appropriate questions, reading turns, and classroom activities from a roster prepared by the regular teacher.
substitute teacher tool student roster classroom turns name spinner
Wheel of Names
SPIN THE WHEEL
Elimination: OFF
Accumulation: OFF
Auto-Spin: OFF
Fair Rotation: OFF
Add entries and spin the wheel.
Entries
Design
Images
Smart ✦
History
+
Undo
Redo
Shuffle
Clear
Upload CSV
Apply List
Spin duration: 4 seconds
Elimination mode
Accumulation mode
Auto-spin
Unique winners
Wheel background image
Add one image behind the colored wheel slices.
Choose background
Image visibility
Remove background No image selected
Center image or logo
Place a logo, icon, or photo inside the center hub.
Choose center image
Center image size
Remove center image No image selected
Image as a wheel entry
Add an image-backed slice with an editable text label.
Choose entry image
Add image entry
Reset all images
Images are optimized and kept in this browser session. They are not included in shared URLs or CSV exports.
Smart Fair Rotation
Prioritize least-selected entries
Winner cooldown Off1 spin2 spins3 spins4 spins5 spins
Pure random mode is active.
100% balance score
0 tracked spins
Reset Smart Stats
Cryptographic Draw Receipt
Creates a tamper-evident record of the result, timestamp, entries and active modes.
No receipt yet
Copy Receipt Download JSON
(()=>{
const r=document.currentScript.closest(‘.wnx-spinner’);
if(!r||r.dataset.ready)return;
r.dataset.ready=’1′;
const $=s=>r.querySelector(s),$$=s=>[…r.querySelectorAll(s)];
const params=new URLSearchParams(location.search),cfg=document.querySelector(‘.wnx-config’);
const mode=cfg?.dataset.mode||r.dataset.mode||’standard’;
const title=cfg?.dataset.title||r.dataset.title||document.querySelector(‘.wn-page h1′)?.textContent||’Wheel of Names’;
const raw=params.get(‘wnitems’)||cfg?.dataset.items||r.dataset.items||’Alice~Bob~Charlie~David~Eve~Frank’;
const palettes=[
((cfg?.dataset.palette)||r.dataset.palette||”).split(‘,’).filter(Boolean),
[‘#6366f1′,’#8b5cf6′,’#ec4899′,’#f97316′,’#14b8a6′,’#3b82f6’],
[‘#ef476f’,’#f78c6b’,’#ffd166′,’#06d6a0′,’#118ab2′,’#7353ba’],
[‘#22c55e’,’#06b6d4′,’#3b82f6′,’#8b5cf6′,’#ec4899′,’#f59e0b’]
].filter(x=>x.length>2);
let colors=palettes[0];
let entries=raw.split(‘~’).map(v=>{try{return decodeURIComponent(v)}catch(e){return v}}).filter(Boolean).map(v=>{
const p=v.split(‘|’);
const weight=mode===’weighted’?Math.max(1,Number(p.pop())||1):1;
return{name:p.join(‘|’),weight,count:0,last:-999,image:”};
});
let angle=0,busy=false,history=[],undo=[],redo=[],spinNumber=0,lastReceipt=null,preSpin=[];
let backgroundImage=”,centerImage=”,backgroundOpacity=.45,centerRadius=76,pendingEntryImage=”,pendingEntryFilename=”;
const imageCache=new Map();
const canvas=$(‘.wnx-canvas’),ctx=canvas.getContext(‘2d’),spin=$(‘.wnx-spin’),result=$(‘.wnx-result’),list=$(‘.wnx-list’);
const elimination=$(‘.wnx-elimination’),accumulation=$(‘.wnx-accumulation’),auto=$(‘.wnx-auto’),winnerCount=$(‘.wnx-winner-count’),duration=$(‘.wnx-duration’);
const balance=$(‘.wnx-smart-balance’),cooldown=$(‘.wnx-smart-cooldown’);
$(‘.wnx-title’).textContent=title;
elimination.checked=mode===’norepeat’||params.get(‘wnremove’)===’1′;
winnerCount.value=mode===’multi’?Math.max(1,Number(cfg?.dataset.count||r.dataset.count)||3):1;
$(‘.wnx-multi-field’).classList.toggle(‘wnx-hidden’,mode!==’multi’);
const escapeHtml=s=>String(s).replace(/[&”‘]/g,m=>({‘&’:’&’,”:’>’,'”‘:’"’,”‘”:’'’}[m]));
const snapshot=()=>JSON.stringify(entries);
const save=()=>{undo.push(snapshot());if(undo.length>25)undo.shift();redo=[];};
const randomInt=n=>{if(n=limit);return a[0]%n;};
function getImage(src){
if(!src)return null;
if(imageCache.has(src))return imageCache.get(src);
const img=new Image();
img.onload=draw;
img.src=src;
imageCache.set(src,img);
return img;
}
function drawCover(img,x,y,w,h){
if(!img||!img.complete||!img.naturalWidth)return;
const scale=Math.max(w/img.naturalWidth,h/img.naturalHeight);
const dw=img.naturalWidth*scale,dh=img.naturalHeight*scale;
ctx.drawImage(img,x+(w-dw)/2,y+(h-dh)/2,dw,dh);
}
function readOptimizedImage(file,maxSize=1000){
return new Promise((resolve,reject)=>{
if(!file||!file.type.startsWith(‘image/’)){reject(new Error(‘Please choose an image file.’));return;}
const reader=new FileReader();
reader.onerror=()=>reject(new Error(‘The image could not be read.’));
reader.onload=()=>{
const img=new Image();
img.onerror=()=>reject(new Error(‘The image format is not supported.’));
img.onload=()=>{
const scale=Math.min(1,maxSize/Math.max(img.naturalWidth,img.naturalHeight));
const w=Math.max(1,Math.round(img.naturalWidth*scale)),h=Math.max(1,Math.round(img.naturalHeight*scale));
const temp=document.createElement(‘canvas’);temp.width=w;temp.height=h;
const t=temp.getContext(‘2d’);t.drawImage(img,0,0,w,h);
const type=file.type===’image/png’?’image/png’:’image/jpeg’;
resolve(temp.toDataURL(type,type===’image/jpeg’?.86:undefined));
};
img.src=String(reader.result||”);
};
reader.readAsDataURL(file);
});
}
const smartOn=()=>!elimination.checked&&(balance.checked||Number(cooldown.value)>0);
function eligibleEntries(){
let pool=[…entries];
if(!smartOn())return pool;
const cd=Number(cooldown.value);
if(cd>0){const cooled=pool.filter(e=>spinNumber-e.last>=cd);if(cooled.length)pool=cooled;}
if(balance.checked&&pool.length){const min=Math.min(…pool.map(e=>e.count));pool=pool.filter(e=>e.count===min);}
return pool.length?pool:[…entries];
}
function segments(){
const total=entries.reduce((s,e)=>s+e.weight,0)||1;
let used=0;
return entries.map(entry=>{const start=used/total*Math.PI*2;used+=entry.weight;return{entry,start,end:used/total*Math.PI*2};});
}
function draw(){
const size=900,center=450,radius=418,segs=segments(),allowed=new Set(eligibleEntries());
ctx.clearRect(0,0,size,size);
if(backgroundImage){
const img=getImage(backgroundImage);
ctx.save();ctx.beginPath();ctx.arc(center,center,radius,0,Math.PI*2);ctx.clip();ctx.globalAlpha=backgroundOpacity;drawCover(img,center-radius,center-radius,radius*2,radius*2);ctx.restore();
}
if(!segs.length){
ctx.beginPath();ctx.arc(center,center,radius,0,Math.PI*2);ctx.fillStyle=’#0b1628′;ctx.fill();ctx.strokeStyle=’rgba(129,140,248,.24)’;ctx.lineWidth=6;ctx.stroke();ctx.fillStyle=’#94a3b8′;ctx.font=’800 34px system-ui’;ctx.textAlign=’center’;ctx.fillText(‘Add entries’,center,center);return;
}
segs.forEach((seg,index)=>{
const dim=smartOn()&&!allowed.has(seg.entry);
const start=seg.start+angle,end=seg.end+angle;
ctx.save();
ctx.globalAlpha=dim?.2:1;
ctx.beginPath();ctx.moveTo(center,center);ctx.arc(center,center,radius,start,end);ctx.closePath();
if(seg.entry.image){
ctx.save();ctx.clip();drawCover(getImage(seg.entry.image),center-radius,center-radius,radius*2,radius*2);ctx.restore();
ctx.globalAlpha=dim?.12:.22;ctx.fillStyle=colors[index%colors.length];ctx.fill();ctx.globalAlpha=dim?.2:1;
}else{
ctx.fillStyle=colors[index%colors.length];
if(backgroundImage)ctx.globalAlpha=dim?.14:.72;
ctx.fill();ctx.globalAlpha=dim?.2:1;
}
ctx.strokeStyle=’rgba(255,255,255,.82)’;ctx.lineWidth=5;ctx.stroke();
const mid=(seg.start+seg.end)/2+angle;
ctx.translate(center,center);ctx.rotate(mid);ctx.textAlign=’right’;ctx.fillStyle=’#fff’;ctx.shadowColor=’rgba(0,0,0,.55)’;ctx.shadowBlur=8;
ctx.font=`850 ${Math.max(18,Math.min(33,350/entries.length+16))}px system-ui`;
const label=seg.entry.name.length>22?seg.entry.name.slice(0,20)+’…’:seg.entry.name;
ctx.fillText(label,radius-34,10);ctx.restore();
});
ctx.save();ctx.beginPath();ctx.arc(center,center,centerRadius,0,Math.PI*2);ctx.clip();
if(centerImage){drawCover(getImage(centerImage),center-centerRadius,center-centerRadius,centerRadius*2,centerRadius*2);}else{ctx.fillStyle=’#0b1628′;ctx.fillRect(center-centerRadius,center-centerRadius,centerRadius*2,centerRadius*2);}
ctx.restore();ctx.beginPath();ctx.arc(center,center,centerRadius,0,Math.PI*2);ctx.strokeStyle=’rgba(255,255,255,.24)’;ctx.lineWidth=10;ctx.stroke();
}
function updateBadges(){
[[ $(‘.wnx-badge-elimination’),elimination,’Elimination’],[$(‘.wnx-badge-accumulation’),accumulation,’Accumulation’],[$(‘.wnx-badge-auto’),auto,’Auto-Spin’],[$(‘.wnx-badge-smart’),{checked:smartOn()},’Fair Rotation’]].forEach(([el,input,label])=>{el.textContent=`${label}: ${input.checked?’ON’:’OFF’}`;el.classList.toggle(‘is-on’,input.checked);});
}
function balanceScore(){
if(!entries.length)return 100;
const total=entries.reduce((s,e)=>s+e.count,0),mean=total/entries.length;
if(!mean)return 100;
const deviation=entries.reduce((s,e)=>s+Math.abs(e.count-mean),0)/entries.length;
return Math.max(0,Math.round(100-deviation/mean*100));
}
function updateDashboard(){
$(‘.wnx-balance-score’).textContent=balanceScore()+’%’;$(‘.wnx-smart-spins’).textContent=String(spinNumber);
$(‘.wnx-smart-counts’).innerHTML=[…entries].sort((a,b)=>a.count-b.count||a.name.localeCompare(b.name)).map(e=>`${escapeHtml(e.name)} ${e.count}
`).join(”)||’No entries yet.
‘;
const status=$(‘.wnx-smart-status’);
if(elimination.checked&&(balance.checked||Number(cooldown.value)>0))status.textContent=’Smart Fair Rotation is paused while Elimination mode is active.’;
else if(!smartOn())status.textContent=’Pure random mode is active.’;
else{const parts=[];if(balance.checked)parts.push(‘least-selected priority’);if(Number(cooldown.value)>0)parts.push(`${cooldown.value}-spin cooldown`);status.textContent=`Smart mode active: ${parts.join(‘ + ‘)}. Dimmed slices are temporarily ineligible.`;}
}
function render(){
list.innerHTML=entries.map((entry,index)=>`⋮⋮ ${entry.image?`
`:”}
− ${entry.weight} +
× ${escapeHtml(v)} `).join(”);$(‘.wnx-empty’).classList.toggle(‘wnx-hidden’,history.length>0);
result.textContent=(selected.length>1?’Winners: ‘:’Winner: ‘)+selected.map(e=>e.name+(accumulation.checked?` (${e.count})`:”)).join(‘, ‘);
createReceipt(selected);
if(elimination.checked){save();const set=new Set(selected);entries=entries.filter(e=>!set.has(e));render();}else{draw();updateDashboard();updateBadges();}
busy=false;spin.disabled=false;if(auto.checked&&entries.length)setTimeout(startSpin,1200);
}
function startSpin(){
if(busy||!entries.length){if(!entries.length)result.textContent=’Add at least one entry.’;return;}
busy=true;spin.disabled=true;preSpin=entries.map(e=>({name:e.name,weight:e.weight,hasImage:Boolean(e.image)}));
let base=eligibleEntries();if(mode===’multi’&&base.length<Math.max(1,Number(winnerCount.value)||1))base=[…entries];
const pool=[…base],selected=[],wanted=Math.min(pool.length,Math.max(1,Number(winnerCount.value)||1));
for(let i=0;i<wanted;i++){const index=choose(pool);selected.push(pool[index]);pool.splice(index,1);}
const segs=segments(),targetIndex=entries.indexOf(selected[0]),middle=(segs[targetIndex].start+segs[targetIndex].end)/2,target=-Math.PI/2-middle,start=angle,delta=((target-start)%(Math.PI*2)+Math.PI*2)%(Math.PI*2)+(5+randomInt(4))*Math.PI*2,ms=Number(duration.value)*1000,startTime=performance.now();
function frame(now){const progress=Math.min(1,(now-startTime)/ms),ease=1-Math.pow(1-progress,3);angle=start+delta*ease;draw();if(progress{if(e.key===’Enter’||e.key===’ ‘){e.preventDefault();startSpin();}};
$(‘.wnx-add-button’).onclick=()=>{const input=$(‘.wnx-new-entry’),value=input.value.trim();if(!value)return;save();entries.push({name:value,weight:1,count:0,last:-999,image:”});input.value=”;render();};
$(‘.wnx-new-entry’).onkeydown=e=>{if(e.key===’Enter’)$(‘.wnx-add-button’).click();};
$(‘.wnx-apply’).onclick=()=>{const values=$(‘.wnx-bulk’).value.split(/n|,/).map(v=>v.trim()).filter(Boolean);if(!values.length)return;save();entries=values.map(name=>({name,weight:1,count:0,last:-999,image:”}));spinNumber=0;render();};
$(‘.wnx-file’).onchange=e=>{const file=e.target.files?.[0];if(!file)return;const reader=new FileReader();reader.onload=()=>{$(‘.wnx-bulk’).value=String(reader.result||”).replace(/,/g,’n’);};reader.readAsText(file);};
$(‘.wnx-shuffle’).onclick=()=>{save();for(let i=entries.length-1;i>0;i–){const j=randomInt(i+1);[entries[i],entries[j]]=[entries[j],entries[i]];}render();};
$(‘.wnx-clear’).onclick=()=>{save();entries=[];spinNumber=0;render();};
$(‘.wnx-undo’).onclick=()=>{if(!undo.length)return;redo.push(snapshot());entries=JSON.parse(undo.pop());render();};
$(‘.wnx-redo’).onclick=()=>{if(!redo.length)return;undo.push(snapshot());entries=JSON.parse(redo.pop());render();};
list.onclick=e=>{const button=e.target.closest(‘[data-act]’);if(!button)return;save();const index=Number(button.dataset.i),action=button.dataset.act;if(action===’remove’)entries.splice(index,1);if(action===’plus’)entries[index].weight++;if(action===’minus’)entries[index].weight=Math.max(1,entries[index].weight-1);render();};
list.onchange=e=>{if(!e.target.matches(‘[data-edit]’))return;save();entries[Number(e.target.dataset.edit)].name=e.target.value.trim()||’Untitled’;render();};
$(‘.wnx-bg-file’).onchange=async e=>{const file=e.target.files?.[0];if(!file)return;try{backgroundImage=await readOptimizedImage(file,1200);$(‘.wnx-bg-status’).textContent=file.name;$(‘.wnx-remove-bg’).disabled=false;draw();}catch(err){$(‘.wnx-bg-status’).textContent=err.message;}};
$(‘.wnx-bg-opacity’).oninput=e=>{backgroundOpacity=Number(e.target.value)/100;draw();};
$(‘.wnx-remove-bg’).onclick=()=>{backgroundImage=”;$(‘.wnx-bg-file’).value=”;$(‘.wnx-bg-status’).textContent=’No image selected’;$(‘.wnx-remove-bg’).disabled=true;draw();};
$(‘.wnx-center-file’).onchange=async e=>{const file=e.target.files?.[0];if(!file)return;try{centerImage=await readOptimizedImage(file,600);$(‘.wnx-center-status’).textContent=file.name;$(‘.wnx-remove-center’).disabled=false;draw();}catch(err){$(‘.wnx-center-status’).textContent=err.message;}};
$(‘.wnx-center-size’).oninput=e=>{centerRadius=Number(e.target.value);draw();};
$(‘.wnx-remove-center’).onclick=()=>{centerImage=”;$(‘.wnx-center-file’).value=”;$(‘.wnx-center-status’).textContent=’No image selected’;$(‘.wnx-remove-center’).disabled=true;draw();};
$(‘.wnx-entry-image-file’).onchange=async e=>{const file=e.target.files?.[0];if(!file)return;try{pendingEntryImage=await readOptimizedImage(file,650);pendingEntryFilename=file.name.replace(/.[^.]+$/,”);const preview=$(‘.wnx-entry-image-preview’);preview.querySelector(‘img’).src=pendingEntryImage;preview.querySelector(‘span’).textContent=file.name;preview.hidden=false;$(‘.wnx-add-image-entry’).disabled=false;}catch(err){result.textContent=err.message;}};
$(‘.wnx-add-image-entry’).onclick=()=>{if(!pendingEntryImage)return;const label=$(‘.wnx-image-entry-name’).value.trim()||pendingEntryFilename||’Image entry’;save();entries.push({name:label,weight:1,count:0,last:-999,image:pendingEntryImage});pendingEntryImage=”;pendingEntryFilename=”;$(‘.wnx-image-entry-name’).value=”;$(‘.wnx-entry-image-file’).value=”;$(‘.wnx-entry-image-preview’).hidden=true;$(‘.wnx-add-image-entry’).disabled=true;render();};
$(‘.wnx-reset-images’).onclick=()=>{backgroundImage=”;centerImage=”;pendingEntryImage=”;entries.forEach(e=>e.image=”);$(‘.wnx-bg-file’).value=”;$(‘.wnx-center-file’).value=”;$(‘.wnx-entry-image-file’).value=”;$(‘.wnx-bg-status’).textContent=’No image selected’;$(‘.wnx-center-status’).textContent=’No image selected’;$(‘.wnx-remove-bg’).disabled=true;$(‘.wnx-remove-center’).disabled=true;$(‘.wnx-add-image-entry’).disabled=true;$(‘.wnx-entry-image-preview’).hidden=true;render();};
duration.oninput=()=>{$(‘.wnx-duration-text’).textContent=duration.value;};
[elimination,accumulation,auto,balance,cooldown].forEach(control=>control.onchange=()=>{updateBadges();updateDashboard();draw();});
$(‘.wnx-smart-reset’).onclick=()=>{entries.forEach(e=>{e.count=0;e.last=-999;});spinNumber=0;lastReceipt=null;$(‘.wnx-receipt-id’).textContent=’No receipt yet’;$(‘.wnx-copy-receipt’).disabled=true;$(‘.wnx-download-receipt’).disabled=true;render();};
$(‘.wnx-hide-panel’).onclick=()=>{const panel=$(‘.wnx-panel’);panel.classList.toggle(‘wnx-hidden’);$(‘.wnx-hide-panel’).textContent=panel.classList.contains(‘wnx-hidden’)?’Show Panel’:’Hide Panel’;};
$(‘.wnx-fullscreen’).onclick=()=>r.requestFullscreen?.();
$(‘.wnx-export’).onclick=()=>{const csv=’entry,weight,count,has_imagen’+entries.map(e=>`”${e.name.replace(/”/g,'””‘)}”,${e.weight},${e.count},${e.image?’yes’:’no’}`).join(‘n’),a=document.createElement(‘a’);a.href=URL.createObjectURL(new Blob([csv],{type:’text/csv’}));a.download=’wheel-entries.csv’;a.click();setTimeout(()=>URL.revokeObjectURL(a.href),1000);};
$(‘.wnx-share’).onclick=async()=>{const url=new URL(location.href);url.searchParams.set(‘wnitems’,entries.map(e=>encodeURIComponent(e.name)+(e.weight>1?’|’+e.weight:”)).join(‘~’));elimination.checked?url.searchParams.set(‘wnremove’,’1′):url.searchParams.delete(‘wnremove’);try{await navigator.clipboard.writeText(url);result.textContent=entries.some(e=>e.image)||backgroundImage||centerImage?’Share link copied. Images stay in this browser session.’:’Share link copied.’;}catch(e){result.textContent=url;}};
$(‘.wnx-copy-receipt’).onclick=async()=>{if(!lastReceipt)return;const text=`${lastReceipt.receiptId}nWinner: ${lastReceipt.result.join(‘, ‘)}nTime: ${lastReceipt.timestamp}nSHA-256: ${lastReceipt.sha256}`;try{await navigator.clipboard.writeText(text);$(‘.wnx-copy-receipt’).textContent=’Copied’;setTimeout(()=>$(‘.wnx-copy-receipt’).textContent=’Copy Receipt’,1200);}catch(e){$(‘.wnx-receipt-id’).textContent=text;}};
$(‘.wnx-download-receipt’).onclick=()=>{if(!lastReceipt)return;const report={receipt:lastReceipt,balanceScore:balanceScore()+’%’,selectionCounts:Object.fromEntries(entries.map(e=>[e.name,e.count]))},a=document.createElement(‘a’);a.href=URL.createObjectURL(new Blob([JSON.stringify(report,null,2)],{type:’application/json’}));a.download=lastReceipt.receiptId+’.json’;a.click();setTimeout(()=>URL.revokeObjectURL(a.href),1000);};
$$(‘.wnx-tab’).forEach(button=>button.onclick=()=>{$$(‘.wnx-tab’).forEach(x=>x.classList.remove(‘is-active’));$$(‘.wnx-pane’).forEach(x=>x.classList.remove(‘is-active’));button.classList.add(‘is-active’);$(`.wnx-pane[data-pane=”${button.dataset.tab}”]`).classList.add(‘is-active’);if(button.dataset.tab===’smart’)updateDashboard();});
palettes.forEach((palette,index)=>{const button=document.createElement(‘button’);button.type=’button’;button.className=’wnx-palette’+(index?”:’ is-active’);button.style.background=`linear-gradient(135deg,${palette.join(‘,’)})`;button.onclick=()=>{colors=palette;$$(‘.wnx-palette’).forEach(x=>x.classList.remove(‘is-active’));button.classList.add(‘is-active’);draw();};$(‘.wnx-palettes’).append(button);});
render();
})();
What is Substitute Teacher Name Picker? Substitute Teacher Name Picker is a free browser-based simple student name picker for substitute-led questions, turns, review prompts, and prepared classroom activities. Edit the sample entries, confirm the eligible list, choose the mode that matches the activity, and spin for a visible random result. Use the teacher-approved roster and lesson plan, protect student records, respect accommodations, and avoid sensitive or disciplinary decisions.
Prepare the list for a visiting teacher The regular teacher should provide an updated roster and note any names that must not be displayed publicly. Remove absent students before the activity and include instructions about accommodations, preferred names, and when students may pass.
📝
Clear roster Use the names or identifiers students normally recognize.
🧭
Simple routine Explain when to spin and whether selected names are removed.
🤝
Student support Keep professional judgment and classroom accommodations in place.
Education resource: UNESCO education resources .
FAQs Can the roster be changed during class? Yes. Add or remove a line at any time and the wheel updates immediately.
Should private student information be entered? No. Use only the minimum name or classroom identifier needed for the activity.
Can repeat turns be prevented? Yes. Enable removal or use the no-repeat wheel.
`:”}